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RIGHT AND LEFT TURNS


Different risks, different realities
By James R. Davis




If all you had to do was ride in a straight line, almost anybody could handle a motorcycle. But in the real world we have to negotiate turns with our bikes. While it is convenient to think otherwise, it is simply not accurate to believe that making a right turn is exactly the same as making a left one except for direction. There really are different risks and realities involved.

For example, in all countries where we ride on the right side of the road, right turns are sharper than left turns, while the reverse is true in the other countries. (This article will focus on the US road model.)

That means that right turns are harder to negotiate than left turns at any given speed. It also means that in addition to being harder to negotiate, if you mismanage the turn and go wide, you will find yourself in a lane of traffic that is running in the opposite direction. In a left turn situation that you mismanage you will find yourself off the road entirely.

Which is more dangerous is largely a function of chance.

If, for example, there are no oncoming cars when you mismanage a right turn, at least you remain on pavement and have the chance of recovering from going wide, but any oncoming cars present you with a head-on collision as an alternative.

Running off the road in a mismanaged left turn may not be worse than taking a tumble, but it could very well involve falling off a mountain.

While making right turns involves greater lean angles at any particular speed than a corresponding left turn, there is usually MORE TRACTION available in a right turn than when turning to the left. This, because most roads are crowned. Thus, while turning to the right the road is cambered into the turn while turning left it is cambered away from the turn.

Left turns effectively provide you a narrower lane for use by your motorcycle. That is, because you must lean a motorcycle in order to make a turn, you cannot ride as far to the left within your lane when making a left turn as you might like without dragging your head or left grip across the center line and into the path of oncoming traffic. Unless there is a retaining wall involved, motorcycles can use their entire lane width when making right turns.

Making a right turn at an intersection is FAR LESS dangerous than making a left turn at that intersection. The most obvious reason being, of course, that you do not have to cross the path of any oncoming traffic to do so. (As an aside, a pedestrian crossing the street at an intersection is FAR LESS at risk if he keeps the center of the intersection to his right rather than to his left because immediate danger comes only from his left and less immediate danger comes from easily visible sources.)

Turning left has two other dangers that are not present when making right turns: (1) The possibility that your side stand is down and, because most road surfaces are crowned, (2) you cannot lean a bike as far in a left turn as you can in a right turn without dragging some part of the motorcycle against the pavement.

One final thought: If you make a left turn across an oncoming traffic lane your danger is not restricted solely to that oncoming traffic. Before you actually make your left turn you must do a head check to the left to insure that someone is not trying to pass you on the left! If you are struck by that passing vehicle YOU ARE TO BLAME as you have performed an unsafe lane change!!!!



WHEEL TRAPS
By James R. Davis


As agile as we know our motorcycles are there are times when two wheels simply are not up to the tasks we present to them - unless we know HOW.

For example, assume you are riding along and notice that there is a trough in the middle of the road extending for as far as the eye can see. It also just happens to be about four inches wide and about one inch deep. Like a magnet, that trough sucks your front wheel into it, the rear wheel obligingly joins it and suddenly your wheels are trapped. You cannot steer out of it.

OK, OK, I can hear it now: 'Get real!'

Fine, so it's not down the center of the road. It's along side and some people would call it a rain gutter.

Or it is down the middle of the road, but it only has one side - they resurfaced the road, one lane higher than the one next to it.

Or you eased off the pavement and there was about a one inch drop to the apron beyond.

Or you are on a surface street and pull over to the curb and your front tire slides right up against the curb, parallel to it.

You get the picture. There are all kinds of traps out there that we don't normally have to deal with but that can be encountered at any time, and you will have no choice but to deal with them.

In every case I described above the problem is that you must either ride up and over one side of the obstacle or you must turn away from that obstacle - both of which turn out to be more difficult than first expected.

The problem, of course, is that you often simply cannot turn your wheel because it *IS* trapped. An effort to turn away from the curb that your front tire is hugging finds that the rear edge of the tire must push against the curb in order for the front edge to turn away from it. A mere one inch of height is sufficient to stop you cold - your bike will fall over before you can turn the wheel.

In this particular case you have no choice but to stop completely, lean the bike away from the trap, and walk the bike free.

Never get within 6" of a raised surface that runs parallel to the direction you are moving!


If the surface is only 1" high you can ride over it without much concern so long as you approach it at any meaningful angle. (Greater than 20 degrees.)

Anything higher than about 1" and you must put as great an angle of attack to it as possible. Ideally you want to cross over it with a 90 degree (perpendicular) angle.

Always approach a trap that you must cross over with more than a 20 degree attack angle.


It is not so much that you should fear that your front tire will fail to get over the trap, it is that you must be concerned about getting your rear tire over it. What happens if your attack angle is low is that you instinctively turn your front wheel into the trap to get over it, so it does, but your rear tire, having a lower attack angle, slides along the trap rather than going over it. This immediately twists your bike into the turn and presents an ever increasing attack angle for that rear tire. At some point (quickly) the attack angle will be sufficient and the rear tire will grab and ride over the obstacle. Unfortunately, while it was sliding along you and your bike turned the front wheel in the direction of the slide. Thus, when that rear tire grabs it is analogous to the classic conditions of a highside. About 2/3s of a second later you will hit the ground.

Before trying to ride over a trap that is relatively close to you, turn away from it and then towards it in order to build the largest attack angle possible.


About 1/2 second before your front tire hits the obstacle, accelerate. That unloads your front shocks. At the same time shift your weight to your pegs and lift your butt off the seat. When the rear tire hits the trap the rear-end of the bike will get quite a vertical jolt - possibly enough to throw you off the seat and cause you to have to fight for control if you have not already raised that derriere.


WEIGHT TRANSFER


What is it, why does it happen, and why should you care?
By James R. Davis




When you change speed (accelerate or decelerate) the weight of your motorcycle (including you) shifts in such a way as to put more or less load on your tires. You do not have to weigh the load on your tires to know this with certainty because you can see it happen by observing your front-end 'dive' when you brake.

Traction is proportional to the weight carried by your tires. Thus, when you brake your front tire gains traction while the rear one loses it. Clearly losing too much traction is dangerous since the result is that your tire will slide.

Despite what you may think, weight transfer can be controlled beyond simply adjusting your acceleration and braking rates. That is, how fast you change speeds is not the only thing that determines weight transfer. Surely you would be interested in minimizing the odds of losing traction during a panic stop? Read on...

Braking Transfers
Ignoring wind resistance, essentially all the forces that try to slow you down when you apply your brakes are at ground level. That is, at the contact patches of your tires. On the other hand, the inertia of your bike works not at ground level, but directly thru its center of gravity (CG.) Since the CG is higher than ground level the resulting net force translates into a torque. In other words, braking does not simply shift weight forward, it tries to shift it down in the front and up in the rear.
The higher the CG is, the greater the torque. (If the CG was at ground level the torque would be zero.) On the other hand, the longer your wheelbase is, the lesser the torque. This is just another way of saying that the amount of weight transfer resulting from a change in speed is a function of the ratio of the height of the CG to the length of the wheelbase.

Gravity is a force. At ground level gravity tries to make you fall with acceleration at the rate of about 32.1 feet per second per second (henceforth shown as fps/sec.) This acceleration is called '1 g.'

'Weight' is just another word for gravity. Like inertia, gravity works directly thru the CG of an object.

When we brake we apply force which we will simply call a braking force. Braking is nothing more than a negative acceleration. Thus, when the total braking force is such that your bike's forward speed is being reduced at the rate of approximately 32.1 fps/sec, you are decelerating at the rate of 1 g. That is, your braking force then equals the weight of the motorcycle (including the rider.) If your motorcycle weights 1,000 pounds, then braking at 1 g means you are applying 1,000 pounds of braking force.

You can calculate the amount of weight transfer involved in any stop knowing only the braking force being used and the ratio of CG height to wheelbase length. For example, if the total braking force is 1,000 pounds, your CG is 20 inches off the ground, and your wheelbase is 63.4 inches long:

Wt.Transfer = Braking Force times CG ratio

Wt.Transfer = 1000 lbs. * 20/63.4

Wt.Transfer = 1000 lbs. * .3155

Wt.Transfer = 315.5 lbs.

[We are here discounting entirely the effects caused by tire distortion and suspension compression. Not because these are not important, but because they are of secondary importance to an understanding of these principals.]

Now, just because the bike weighs 1,000 pounds and is sitting on two wheels does not mean that at rest there are 500 pounds on each wheel. Here again we need to know something about the bike's CG. Only if the CG is exactly in the middle of the bike (between contact patches) will the weight be evenly distributed. If the CG is closer to the front wheel than the rear one, for example, then there will be more weight on the front tire than on the rear when the bike is at rest (not moving.) Further, unless there is an upward or downward movement of the bike, the sum of the weight carried by the front and rear tires must equal the total weight of the motorcycle and rider.

Let us assume that at rest the weight is evenly distributed. Then we now know that while braking at 1 g, because of weight transfer, there will be 815.5 lbs. (500 + 315.5) on the front tire and only 184.5 lbs. (500 - 315.5) on the rear tire. Because traction is a function of weight carried by a tire it is clear that there is not a lot of traction left on the rear tire at this time.

Let us look very carefully at what this weight transfer example is showing us. You have heard that you have about 70% of your stopping power in the front brake. This example shows that we have applied 1,000 lbs. of braking power to the tires of the bike. If it was ALL the result of using only the front brake, then we have wasted what traction is still available to us from the rear tire and, worse, we have locked our front tire and started a skid! This, because virtually all standard tires lose their 'sticktion' (stick/friction) when confronted with more than about 1.1 g of braking force. With 815.5 lbs. on the front tire it could with reasonable confidence handle a braking force of 897 lbs. (1.1 * 815.5), yet we applied 1,000 lbs. to it. At least in this case our front brakes could deliver nearly 90% of our stopping power, not just 70% - but not 100%, either.

Now let us look at what would happen if the CG happened to be 30 inches high rather than 20:

Wt.Transfer = Braking Force times CG ratio

Wt.Transfer = 1000 lbs. * 30/63.4

Wt.Transfer = 1000 lbs. * .4732

Wt.Transfer = 473.2 lbs.

The front tire would have 973.2 lbs. of weight on it and the rear would have only 26.8 lbs. This is close to doing a 'stoppie'!!!

What we are beginning to see is that if the CG gets to a height of 1/2 of the length of the wheelbase we can expect to do a 'stoppie' if we use 1 g of braking force. Further, if we use even the slightest amount of rear brake in such a configuration when we are slowing at the rate of 1 g, we can expect to lock the rear wheel.

One more example - we will attempt a 1.1 g stop with this 'higher' bike:

Wt.Transfer = Braking Force times CG ratio

Wt.Transfer = 1100 lbs. * 30/63.4

Wt.Transfer = 1100 lbs. * .4732

Wt.Transfer = 520.5 lbs.

At this point we have transferred MORE than the entire weight which had been on the rear wheel - we have left the rear wheel with NEGATIVE 20.5 lbs. on it. i.e., our rear wheel has been lifted off the ground!!!!

Notice, please, that the CG does NOT remain at a constant height during aggressive braking. If we use exclusively front brake, then the front-end will dive and the rear-end will lift. This could result in the CG remaining at the same height, but more likely it will get higher. We have already seen that a higher CG means more weight transfer. Further, as the front-end dives the result of the compression of the front shocks is a shortening of the wheelbase of the bike. This, like raising the CG, results in a higher CG to wheelbase ratio, and therefore more weight transfer. [As an aside, if your bike has an anti-dive feature (TRAC, for example) then MORE weight transfer occurs to the front wheel than without it. This, because the CG is held higher. In other words, anti-dive INCREASES the odds of sliding your rear tire!]

If only the rear brake is used there will be a weight transfer to the front tire which will tend to compress the shocks. Additionally, however, use of the rear brake tends to LOWER the rear-end of your motorcycle and lengthens its wheelbase, (the swing arm become more level). The net effect is to lower the CG of the bike. This offsets neatly the fact that the compressing front-end shortens the wheelbase at the same time. However, since there is a weight transfer, the rear-end gets lighter while braking which quickly limits how much braking power you can apply before you skid that tire. In other words, you must use the front brake for maximum stopping power.

From the above discussion I think you can now see that the use of your rear brake along with the front brake leads to less weight transfer than if you use only the front brake, and why the use of both at the same time always results in maximum stopping power.

When a rider mounts his motorcycle he both raises the CG and moves it towards the rear. The heavier the rider, the more significant these changes to the CG are. We already know that as the CG rises it causes more weight transfer during speed changes. This raising of the CG is far more significant than is its shift towards the rear. (This, because the height of the CG is small compared to the length of the wheelbase.)

What this adds up to is that the heavier the driver of the motorcycle, the easier it is for braking to cause a breakaway of the rear-end. Is there anything that can be done to mitigate this potentially deadly problem? You bet! In a panic stop the driver should bend from the hip and elbows and lean forward! This will cause the CG to lower and move forward. A lower CG is more significant than its slight movement forward. In summary, there will be less weight transfer with him leaning forward than if he was sitting straight up in the saddle, there will be less compression of the front shocks, and less shortening of the wheelbase. i.e., less likelihood of losing rear-end traction.

Anything else? Yep. Always pack your saddlebags with heavy items towards the bottom. Every pound below the CG lowers it, every pound above it raises it.

Accelerating Transfers - Straight Line
This article has so far focused only on weight transfer associated with braking. It should be obvious that exactly the same phenomenon happens when you accelerate - the amount of weight transferred is determined by your rate of acceleration and the CG ratio (height of CG divided by length of wheelbase.) Though you may not believe that you have an 'anti-dive' component for your rear wheel like you may in the front, you do. The rear wheel does not push the frame forward directly. It pushes its 'swing arm' forward. Since the swing arm pivots on the frame aft of your CG, and since that pivot is almost invariably higher than where the swing arm attaches to the rear wheel, any accelerating force applied thru the rear wheel tries to lift the frame of the motorcycle. i.e., rather than calling this an 'anti-dive', think of it as an 'anti-squat'. This keeps the CG higher than it would be otherwise and the result is that there is greater weight transfer to the rear tire (and correspondingly higher traction results.)
Accelerating Transfers - In A Curve
Constant Speed
And what about weight transfers when you are in a curve? You have heard the terms 'over-steer' and 'under-steer' before, I'm sure. Over-steer means that when you are in a curve your rear wheel is more likely than the front one to lose traction (ie, your sliding bike will end up pointing towards the inside of the curve.) while under-steer is the opposite. Weight transfer to the rear tire from acceleration leads to over-steer (greater slip angle on rear tire) while braking in a curve, because of weight transfer to the front, leads to under-steer (greater slip angle on front tire.) Both are deadly concerns if you push tire loads to their limits!! (On the other hand, if you have a choice you would almost certainly want a little over-steer rather than under-steer because a brief slide of the rear tire is easier to correct than a similarly brief slide of the front tire.)
It would be a deadly mistake to try to use the kind of weight transfer analysis we have discussed so far in an effort to learn how much acceleration to use while in a curve to equalize tire loads! (I now assume that you have read and understand the article entitled 'Delta V'.) The weight transfer calculations we have been looking at so far deal with consequences of longitudinal acceleration. In a curve you are also subject, even if maintaining constant speed, to centripetal acceleration.

Unlike longitudinal acceleration (changing your speed), which changes your tire loading in a simple proportion to the CG ratio, centripetal acceleration increases tire load in proportion to the SQUARE of your change in speed. The formula to determine these forces is:

Force = Mass times Velocity squared divided by Radius
F = M*V^2/R
You can assume that most street tires will lose traction when they are subjected to about 1.1 g of force. So how do you tell whether you are close to 1.1 g when in a turn? Simple. If your effective lean angle is 45 degrees, you are experiencing 1 g of centripetal force. And, from the formula above you see that the force is extremely sensitive to velocity. This means that a very minor increase in speed could easily push you past the 1.1 g limit.
What you should understand from this is that using acceleration (speed change) to balance tire loads while in a curve is foolish. (In general, however, you will want some (minor!!!) acceleration in a curve as this tends to increase the slip angle of the rear tire which increases traction, and because you want your rear-end suspension modestly loaded to enhance control.)

Now you know why you want to be sure the load distribution on your bike is set properly BEFORE you hit the road.

Accelerating Transfers - In A Curve
Exiting The Curve
While a modestly increasing speed makes great sense while you are riding thru most of a curve, it is understood that some people find great pleasure in rolling-on their throttle as they exit those curves.
Just a little thought, based on all that we have talked about so far, should now convince you that you must be conservative in this practice while you are leaned over hard, and that you need to be BOTH widening the curve and standing the bike taller as you do it.

Rather see the effects of weight transfer instead of doing the calculations? If you have Excel on your system then just take a look at this spreadsheet/model. With it you can modify any of the inputs shown and observe the effect of the changes. Below is a sample screen displayed while using the model.

This example shows a heavily loaded motorcycle weighing 1,050 pounds having a Center of Gravity closer to the rear wheel of the bike than the front which is traveling in a curve with a radius of 450 feet with a speed of 50 MPH. The information in the spreadsheet assumes constant speed.

The chart to the right shows lateral (sideways) force divided by vertical force (load) for each wheel as a function of acceleration. At zero acceleration the ratio is .37 and, you will note, is lateral acceleration (i.e., it is .37 g). Notice that the effect of acceleration is radically different between the front and rear tires.

In the case of the front tire, acceleration merely reduces loading because of weight transfer. Thus, traction is diminishing in proportion to that acceleration (i.e., traction is a function of the types of material that are being pressed together and the force pressing them together - since the load is diminishing due to weight transfer, so is traction.)

The effect of acceleration on the rear tire is quite different, however. You would correctly assume that weight transfer resulting from acceleration would increase traction on the rear tire. It does, during modest acceleration. But acceleration (increasing speed) is accomplished using the rear tire only. That is, there is no longitudinal acceleration affecting the traction of the front tire, just the rear one. Longitudinal acceleration and lateral acceleration are vectored, which means the resulting acceleration force is the square root of the sum of the squares of those forces. (In other words, more than either of them, but not as much as both.) As the rate of acceleration increases it quickly overwhelms the effect of increasing load on the tire (which increases traction) and begins to CONSUME THAT TRACTION FASTER THAN IT IS BEING ADDED. This is shown in the curved line in the chart.

So what do the lines ultimately show? If you assume that the coefficient of friction for your tires is approximately 1.1, then when either line reaches 1.1 on the chart that tire will lose traction and skid! The higher the line, the closer to a skid (i.e., the less traction is left.) If you increase speed or decrease the radius of your turn, your lean angle will get larger. When your lean angle gets to 45 degrees, the lines will start at 1.0 and even a slight acceleration will push the lines over 1.1 - which means you will soon be exploring the joys of road rash.

In summary, there are a few obvious reasons to care about weight transfer:

Traction is directly proportional to the amount of weight carried by a tire - managing weight transfer is managing traction.

Misloading your motorcycle can result in substantial handling problems - particularly in a curve.

In order to manage weight transfer intelligently you need to have a good idea of where the center of gravity of your bike is and what happens to it when you add a passenger or luggage.

Traction will probably be lost if tire load exceeds about 1.1 g. If you are in a curve and are leaning at 45 degrees, you already have 1.0 g tire loads. Enough is enough.

Stopping with your elbows locked guarantees more weight transfer and a higher center of gravity - both undesirable from a control point of view.

Rolling-OFF your throttle (or braking) if you are 'hot' in a curve is almost certainly more dangerous than simply leaning farther into the curve - because weight transfer will unload the rear-end which reduces rear tire traction.
Under-steer and Over-steer both yield slides when load limits are reached - balancing the weight reduces the risk.

PICKING UP A BIKE- BY YOURSELF

By James R. Davis




OK, so most motorcyclists go to a parking lot to practice riding skills, not to dump their bikes so they can have the pleasure of picking them up again. I guess Elaine and I are not exactly 'normal' - we like to think of ourselves as 'odd ducks' - because a few weeks ago we did just that.

After Elaine practiced driving the Wing by herself I had her dump it on its left side for me. Though she was not going to try to pick it up herself, since she had never dumped the Wing before I wanted her to learn how to do it without ending up under the thing.

She dumped it on grass covered firm ground and then I approached the bike and considered all I had heard about how to pick up 900 pounds of bike by myself. I weigh in at only about 160 lbs. and am only 5'8" high. Frankly, I wasn't at all sure I could do it and had studied the advice of others to try to avoid doing something that could hurt me.

Virtually everything I had read in the past on the subject argued that you are not to try to lift the bike with your arms or back - that you should use the largest muscles in your body instead - your legs. So that is exactly what I intended to do - and this practice event would be more learning than practice for me as I had never before tried to pick up a down Wing by myself.

Let me tell you that a dumped bike on grass is harder to pick up than one on the street for two reasons:

The case guard and rear guard dig into the ground just a little, but that makes the lean angle of the down bike significantly more than it would be if it were lying on pavement.

Getting good traction with your feet on grass can be iffy at best.


The significance of the fact that the bike rests lower when on ground versus pavement is that you are often unable to get a low enough purchase on it to bring it up without lifting. That is, the secret to 'picking up' a big bike by yourself is that you PUSH it up rather than LIFT it up, and if it is laying over at more than a 45 degree angle you will have to do some lifting!

The smaller the angle of lean (relative to vertical), the easier it is to make that angle still smaller. In other words, it is the first inch or so of movement that is the hardest. So, the very first thing you should do is try to get the lean angle to be as small as possible. If you are on an incline, for example, twist the bike until its tires are facing downhill.

The next thing you do is to turn the front wheel as far as possible TOWARDS the ground. If possible, turn it to its stop and lock it in place. (I found that on the ground I could not get mine turned all the way - perhaps I am not strong enough, or the bike was leaned too far over.) You may have to jerk hard on the handlebar to get the wheel turned, but this is a very important step. Why? Because by turning the wheel towards the ground the frame of the motorcycle is lifted off the ground. This means you are reducing the lean angle before you even begin to try to pick up the machine.

If the bike happens to be on its left side, you should check that the side stand is up, if possible. If it is on its right side, you MUST make sure the side stand is down (before you pick up the bike!.)

If possible, insure that the bike is in a low gear or, in the case of some GoldWings, in reverse, so that there is minimal chance of the bike rolling when you get it back on its wheels.

Next, you are going to plant your butt (not your hip) on the seat. So, face away from the motorcycle and lean against the seat such that the top half of your cheeks are above your contact with the seat and the bottom half are pressed solidly against the seat. Your feet should be spread no wider than your shoulder width and planted FIRMLY (you are wearing RUBBER SOLED boots, right?) on the ground away from the bike by about three feet. Your knees should be bent at about a 40 to 50 degree angle - anything more than that and you will probably not be able to straighten them. Indeed, though you want some bend, the less bend in your knees that you can manage, the easier this effort will be - what limits your choice is the length of your legs.

Now you need to grasp your motorcycle with your hands on both sides of your body. You need to hold onto firm structures, but because you should not be doing anything with your hands other than guiding and possibly a little lifting when you start, they can be parts of your fairing, a firmly mounted part of your backrest, a passenger handrail, under your seat, or handlebar. What you hold is not very important except that it is firmly attached (no give) and is conveniently located.

Now simply walk backwards as you PUSH against the seat. (I remind you that if the bike has a lean angle of 45 degrees or more you must also LIFT - be careful!)

As you approach vertical the vast majority of the bike's weight will be on the tires. Proceed slowly so as to prevent going too far and causing it to fall over on its other side. Once vertical, still facing away from the motorcycle, fish for the side stand with your left foot and bring it down. Then just let the bike lean over onto the stand.

If the bike had been on its right side when you started you already made sure that the side stand was down. So, in this case you simply ease the bike past vertical and let it come to rest on that side stand. Please note that if you are on an incline, my earlier instruction had you twist the bike such that the wheels face down slope. In this case you will need to be VERY careful about how fast you let the bike go past vertical or you may find yourself having to pick it up again from the other side! Indeed, it may be impossible for you to ease it past vertical without losing control of the bike again. (In this case I would try to change my body position so that it is facing the front of the bike (while it is vertical) and try to push the bike to a more level location - but REMEMBER that your side stand is down!)

So now you know what I learned out there on the parking lot with Elaine. I was successful in picking up my GoldWing by myself after she dumped it on its left side - but because of the very severe lean angle caused by the fact that the guards dug themselves partly into the dirt I had to do considerable lifting at the beginning. This left my upper thighs sore from the effort. Still, I had done it and the feeling of success was more important than the slight quivering of my thigh muscles.

I had Elaine dump the bike again, this time on its right side. After insuring that the side stand was down and locked I successfully repeated the lift maneuver by myself. Again, my upper thighs were sore as a result. But let me tell you how happy I was to discover that I could actually pick up a dumped GoldWing by myself!! It was not easy, but nobody expected it to be - though it was easier than I expected it to be.

This is after all why we went out to the parking lot - to practice what we each felt was hard for us individually - so that whatever it was would become easier.



BEFORE YOU DISMOUNT

Six things to do
By James R. Davis




We all have our own unique way of doing things. Some people, for example, do exactly two things before they dismount their bikes: they turn off their ignition switch and they put down their side stand. Given a little thought about it, however, I think there are a few more details to attend to (however 'uniquely') before we dismount our motorcycles, and if we make a habit of doing them we can avoid some major trouble for ourselves.

Use your engine cutoff switch to shut off your engine

Some people seem to think that switch is there for use only in an emergency. Not true. The reason you use the engine cutoff switch rather than the ignition switch to shut off your engine is because you do not have to take your hand off the grip in order to do so. Further, if you make a habit of doing so you will build 'muscle memory' as to where it is so that you can quickly and unerringly find it in the event of an emergency. Turn your ignition switch off




Obviously, unless you do this your lighting system is still on and your battery is discharging. By the way, it is good form to get into the habit of using your LEFT hand to turn off the switch (if possible) so that you can keep your front brake lever activated.

Turn your fuel valve (if you have one) to the OFF position


A stuck needle valve in one of your carbs can allow a great deal of gasoline to leak past it. If a needle valve should happen to stick while your motorcycle is left in your garage overnight, that leaking gasoline can cost you your house and your life. When you start your motorcycle you should always turn your fuel valve to the RUN/ON position. Thus, by making it a habit of turning the valve off at night you also eliminate the risk of having left it in the reserve position (had it been there when you last dismounted) and running out of gasoline on the road somewhere. Put your side stand down - and confirm that it is locked in place




After leaning the bike onto the side stand you have insured that it is stable from side to side before you try to dismount. (Your bike should be in first gear and you should push the bike forward until all the play in your gears is gone before leaning the bike onto the side stand.) Turn your handlebars full-lock left




A motorcycle is several times more resistant to movement when the front wheel is not pointing straight ahead. Even a gentle nudge from behind can cause a motorcycle that is on its side stand to roll forward unless the front wheel is not pointing straight ahead. Squeeze the front brake lever




If you build these six steps into a habit that you always perform before dismounting, you are serious about ALL aspects of motorcycle safety.

The ride is not over until you are safely dismounted.




HANDLING CURVES- A BETTER LINE

By James R. Davis




Taking curves is rather a personal choice in terms of selection of entry and exit points as well as speed, it seems to me.

For example, the typical advice I have heard from others is to chose an entry point that allows you to make the curve using the smoothest line thru it so that you always have the least lean demand. This, of course, gives you the most ability to compensate your path through the curve should you find a need to do so. It also means that you hit the apex of the curve at about its middle. That is, you enter from the outside edge of the curve, then move towards the inside until you reach its apex, then continue from there outwards until you are once again at the outside of the curve just as you exit it.

I, on the other hand, do not normally do this. I prefer to delay my entry into the curve. That is, I stay to the outside edge well past the normal entry point, then turn much more sharply into it and hit the inside much beyond the normal apex. This gives me two significant (to me) advantages over the 'smoothest' course:

I get the lean that I enjoy (read: crave!) in the beginning of the curve where I have seen all that I need to see in terms of potential trouble.

When I exit the turn I am traveling at a much reduced angle relative to the path of the road. That is, since I am closer to the end of the curve when I reach the inside than is the normal apex, I have fewer degrees of the arc left to go before I am again going in a straight line. Said differently, if the road changes directions by a matter of 90 degrees through a curve, no matter what path you select through it you will have totaled 90 degrees when you are out of it. Since I turn more into the curve at my delayed entry point, I have less left to go to complete the turn when I am near the exit.


This last advantage is of profound importance, in my opinion. This gives me far more ability to handle unexpected problems as I get closer to the end of the curve. For example, what if it turns out to be a decreasing radius curve after all, or if there is gravel in the road that was not visible at its entry?

By the way, when I said that 'I stay to the outside edge' above I in no way meant to imply that I get close to the line. Far too many people seem to think that they have performed a safe maneuver thru a curve so long as their wheels do not touch or cross the (center) line. WRONG! If any part of your motorcycle crosses that line, including just a grip, you are in the path of oncoming traffic, and are in THEIR lane.

In any event, I TRY to overshoot my entry to a curve. Then I aggressively push-steer into it, and delay reaching the inside of the curve well past its apex. This also, incidentally, allows me to start an aggressive roll-on of my throttle sooner than when I am at the inside of the curve which gives me a better handling bike through the majority of it. I should add that this delayed entry approach requires that you get in the habit of not entering the curve too fast. Further, the right approach speed is one which requires NO BRAKING at entry.

[You should use MODEST throttle roll-on all the way through any curve. The 'roll-on point' that is shown in the graphic is where you can go after a higher exit speed if you happen to be aggressive with your bike.]

If you find that you cross the outside line, ever, then it is time to reassess what you are doing. Approaching the curve too fast? Insufficient confidence to aggressively push-steer when you need to? Insufficient experience to pick a good line? Lack of respect for the laws of chance (one of those times a 4-wheeler will have two of them across the line)? Acting like riding with friends is a competitive sport? Whatever it is, if you ever cross that center line you are riding above your abilities (and everyone around you will know it) and you need to change something soonest. Otherwise, make sure your relatives know your intentions relative to the donation of your organs.

This method is just my preference, after all, and it seems to me is generally safer than the 'smoothest line' method usually described.




128 WAYS TO DUMP YOUR BIKE

Compiled from the rec.motorcycles newsgroup by Scott Harpster
1 Putting your foot into a hole when stopping.
2 Putting your foot down on something slippery when stopping.
3 Locking the front wheel during overenthusiastic braking.
4 Missing the driveway and sliding on the grass.
5 Not putting the kickstand down when getting off.
6 Make a turn from stop in gravel or sand at high throttle.
7 Not putting a board ('foot')under the kickstand on asphalt on a hot day.
8 Letting overenthusiastic people sit on your bike who have never been on a bike.
9 Forgetting the bike's in gear when you jump on the kickstarter.
10 Revving the engine, releasing clutch, and putting feet on pegs when the light turns green, but the bike's in neutral.
11 Not putting your foot down when stopping at red light.
12 Losing balance when putting it on the centerstand.
13 Take an hour ride in 30 degree weather with no gloves, stop at a stop sign and pop the clutch when you start because you've lost feeling in your hands.
14 Putting your foot down at a toll booth on the thick layer of grease that builds up when cars stop.
15 Using too much power when you pull out of a greasy toll booth.
16 Ignoring the sand that builds up in the spring at the side of the road (in places where roads are sanded and salted in winter.)
17 Kicking your kickstand in a cool fashion and having it bounce back up instead of staying down.
18 Getting off your bike while it is running and forgetting that is in gear.
19 Trying to kick start your first bike over and over because you didn't realize that it was really out of fuel, and getting the goofy metal ring on the side of your boot caught in the kickstarter, causing you (and the bike) to go over on the right side.
20 Starting your brand-new electric-start trail-bike, riding around an ornamental shrub on full left lock, throwing it to the right and accelerating to wheelie over the curb onto the street and _then_ discovering that you hadn't unlocked the steering-lock...
21 On same bike, getting the dual-range lever caught inside your jeans as you come to a stop...
22 Having your boot/jeans catch the gear-lever and putting your running bike into first gear whilst reaching for the side-stand (which is why I now automatically pull in the clutch whenever deploying or retracting the stand.)
23 Having "green" racing linings which have much higher coefficient of friction on the slight rust that forms on the polished drum when you've not ridden for a few hours, and lose the front-end holding the brakes on against the throttle to wear off the rust.
24 Having a three-cylinder two-stroke that's so smooth you think you're in second when you're actually in first, so you spin out when the undercarriage touches down in a tight corner passing a car and you think, "just a bit more throttle will help here..."
25 Revving bike in impressive squidly fashion at red light, thinking it's in neutral; dropping clutch and standing in place while bike wheelies and backflips into intersection.
26 Having your fat-ass brother (as a pillion) lean waaay over to the side to look at something on the ground while at a stop sign.
27 Wife gets foot caught on saddlebag while getting on before you.
28 Rebuild carbs and treat bike like it still needs full gas away from a stop.
29 Bald tires, and a smatter of rain.
30 Look at the sand at the edge of the exit ramp rather than through the turn.
31 Neither you nor your dad watching while he's backing his car up to the woodpile to unload wood.
32 Not putting the pin that holds the center stand all the way in and then trying to put the bike on the center stand.
33 Trying to hold the bike upright before deploying the center stand only to find your knees are too weak from riding.
34 Park behind friend's mom's minivan figuring "If anybody goes anywhere, they'll surely see it. 'specially since there'll be 5 of them getting into the van.
35 After getting fuel at gas station and holding the bike level with your legs in order to fill it completely, jumping off forgetting that your legs were holding it upright not the kickstand.
36 Entering a DR ("decreasing radius") turn too fast. This is especially dangerous when making a right turn where if you attempt to straighten up and brake, you'll plow into oncoming traffic.
37 Trying to countersteer (or wheelie) your shaft driven bike? [Obviously the person who posted this doesn't have a clue.]
38 Getting your boot/ shoelace caught on the gearshift. (I wear laceless boots now.)
39 Attempting to kick start a cantankerous '84 CR500, whilst standing on a picnic table bench, and she *kicks* back!
40 Getting pissed off for dropping it in the first place, yanking it vigorously off the ground, only to have it drop to the _other_ side.
41 Pulling out the swing arm stand, and forgetting to put the sidestand down first.
42 Backing down an inclined driveway, turning to either side with a full tank of gas.
43 Taking the bike off the centerstand and forgetting the sidestand.
44 Riding on wet grass with street tires (Almost as bad as ice!!)
45 Riding on wet asphalt with dirt tires (Almost as bad as ice!!)
46 *Thinking* the kick stand was down when it wasn't.
47 Kick stand slowly burying itself in hot asphalt.
48 Kick stand slowly burying itself in soft ground.
49 Backing up perpendicular to a steeply sloped driveway and attempting to put your foot down on the downhill side while on a large bike with a high seat. (By the time your foot reaches the ground the bike is so far off center balance you won't be able to hold it up.)
50 Backing your bike down a plank, by yourself, from the bed of a pickup truck. Works great as long as you remember that once you start moving, stopping for any correction is out of the question. Get two people to stand on each side of you and the bike.
51 Losing your balance when coming to a stop because of fatigue from a long trip. The wind and the buzz of the bike induces an unexpected case of vertigo. Stop often and rest.
52 Riding beyond your limits while trying to keep up with someone who is probably riding beyond their own. Always a temptation. The best riders/racers understand and use discipline when riding.
53 Not paying attention. Always strive to anticipate what could possibly go wrong and be planning what you're going to do when it happens, eventually it will - and you'll be ready, instead of surprised when you're much more likely to do something stupid and reactionary.
54 Assuming that all wet roads are created equal. They are much more slippery when it first starts to rain - until the oil and dirt are washed away.
55 Assuming that the condition of a blind corner is the same as it was the last time you rode it. Instead you find sticks, road kill, oil, rain wash, stones, pot holes, garbage, etc.
56 Not understanding how to get set-up for a corner when pushing the limits. In most cases the bike could have made the corner but the rider decided it couldn't and while in a panic attempted to correct the situation with the brake. WRONG! MSF course will discuss this at length.
57 Riding without all of the protective equipment because I forgot to bring it and after all it was just this one time. Turned out to be the wrong time! I forgot my MX boots and fell on a steeply banked corner and the foot peg attempted to drill into the back of my right calf. On crutches for 3 weeks with a deep bruise.
58 Using a little too much power turning the first corner after you've put on new tires (with that nice slippery release compound on them).
59 Being too short for the bike you're riding, and coming to a stop sign.
60 Your rider hops on before you are ready.
61 Pushing your bike into the garage and letting it get leaned just a little away from you, pulling you on top of it to the ground.
62 Pulling off both fork caps while the bike is on its centerstand.
64 Park pointing downhill, don't leave it in gear.
65 Park with sidestand facing up hill, sidestand is too long.
66 Allow friend to ride bike that has either no riding experience, or only tiny dirt bike riding experience (they will wheelie out of control, fly straight at the nearest object, or drop it attempting to stop suddenly.)
67 Pulling into Dairy Queen and slipping on a spilt chocolate malt.
68 Sitting on your bike on an inclined driveway talking to a very pretty girl, forgetting where in the hell your mind is and then noticing that it's already too close to the ground to stop.
69 Change rear-end oil on a shaft drive bike, spill 90w on tire, don't clean it up and then make a really sharp turn out of the driveway. *Splat*
70 Parking your bike so that it stands upright with the kickstand down and then having a slow leak in the rear tire which causes the kickstand to push the bike over.
71 Running into a bus after a 120mph+ high speed chase where there is helicopter pursuit and you are being taped by 5 local news stations.
72 Spending 3 hours washing and waxing your bike and then stepping back to admire it with some buddies and then watch it fall right off its side stand while it was warming up.
73 Pushing it over.
74 Covering it with a windsail (aka canvas cover) and letting the wind push it over.
75 Unbolting too many components from the back so that the bike falls off the jack.
76 Having an internally rusted CX500 center stand come apart whilst putting the bike onto it.
77 Discovering when you stop and try to put your foot down that the kickstart lever is up your pant leg.
78 Letting your wife drive the bike and having her stall it on an inclined driveway while in a 45 degree angle to the incline.
79 Entering a banked freeway onramp with a stoplight at the end, and realizing a little too late that the downside is just a _little_ steeper than you thought.
80 Whacking the throttle open on the highway when you think there's no cop around then slowing to normal speed again only to realize that a trooper has been trying to catch up with you for two miles and he's pissed so he decides to run you off the road because he thinks you were trying to run away from him, even though you explain to him that if you were trying to run that he wouldn't have caught you then getting out of any ticjet because *@!!$#, uh I mean cop, felt bad even though he never said "I'm sorry" . . . .but I'm not bitter.
81 While pushing your bike in an attempt to start it by compression, jumping on side-saddle with excessive vigor.
82 Successfully compression starting your bike while running along side, only to find out that you'd held a BIT too much throttle!
83 Deploying the centre-stand without noticing that the ground falls away on the other side.
84 Taking the wife on a ride on your brand new, first bike in 20+ years and making a slow, tight, turn on gravel.
85 Riding in stilettos and getting stuck on the footrest.
86 Swinging your legs too enthusiastically over the bike with tight trousers on and kicking it over.
87 Dismounting while trying not to wet yourself (cold weather..tuh!)
88 Riding short distances side-saddle fashion.
89 Pulling off with a blood alcohol level exceeding the stated limit.
90 Reaching down to pick up your gloves/keys/glasses.
91 Paying too much attention to the tiltometer on your valkarie.
92 Dropping your dirtbike on the side of a steep hill covered in pine humus, then while getting it righted go over the down side because it's too far of an angle to get a foot down.
93 Trying to ride away on the side of a steep hill covered in pine humus which is slipperier than sand.
94 Bopping down the freshly-oiled farm lane to see the neighbor kid with my brother on the back, cautiously toeing the rear brake, feeling the rear wheel slide as we headed straight for the barn, grabbing a panicky handful of front brake, doing a slow highside despite dabbing mightily, sliding right up to the barn door prone on the well-oiled bike with my brother on top of the pile, and hearing the neighbor say "Didn't that thing used to be orange?"
95 kill the bike while leaned over trying to make a slow, sharp turn in a parking lot.
96 Forgetting to remove the disc lock and taking off from the curb with haste...Tends to break the front caliper, too.
97 Falling asleep.
98 Getting help from a neighbor in pushing your 750 up a steep ramp into a moving truck. Though he might assure you that he used to ride a motorcycle, it turns out it was a 125 in Bombay. He gets 2/3 of the way up the ramp, looks panicked, and his knees buckle. Crunch.
99 Looking at the pretty curb to your left on a right-hand bank.
100 Trying to get a wasp or bee out of your jacket while sitting on the bike.
101 Trying to start out in a quick turn (leaning in anticipation of giving it throttle) and stalling it out because the engine hasn't warmed yet - it's a nice, slow drop...
102 Forgetting to put in oil after an oil change. Starting 'er up, and wondering why the low oil pressure dummy light doesn't turn off.
103 After a brake job, forgetting to pump the lever/pedal a few times, and taking off, wondering why there's no brakes as you're coming up on the intersection.
104 Having a mechanical gate close on you as you're trying to ride through.
105 Hitting that patch of sand which has washed across the road on a blind bend.
106 Absentmindedly putting the bike on the kick stand and walking away before you check to see if the driveway is level.
107 Applying your usual amount of throttle but with a passenger behind you ... "cool ... look at that plane".
108 Pushing your bike into a crowded garage, letting it get leaned just a little away from you, pulling you on top of it into your vintage MG.
109 Popping a wheelie while showing off for a girl, almost looping it, slamming on the rear brake to compensate, and passing out from the bollocking several yards later.
110 Assuming the puddle of liquid behind the convenience store was water when it was actually used motor oil.
111 Starting bike while habitually squeezing clutch lever, standing to the left of the bike, remembering too late that the bike is in gear. Realize too late that the choke gives the bike enough power to drag you 30' across the parking lot in first gear.
112 On your third ride with your first ever bike. Stop at a red light. When the light turns green, you have to start uphill, and turn right at the same time. Somehow that overwhelmed me.
113 Parking on a bit of an incline (slopes down right to left), having your left foot slip a little when getting back on the bike, and slowly loosing your balance.
114 Let your buddy ride it. And if you are really stupid let him ride it again.
115 Turning onto a busy street and in the middle of the turn you suddenly remember that this street has trolley tracks.
116 Put armor all on your tires to make them look nice and pretty and then ride on the white safety lane line as you take a HARD right turn at 35mph.
117 Throw a party and get together with a random girl on your bike in the garage while extremely drunk.
118 Pull into parking and failed to ensure proper extension of the sidestand then with near perfect execution of the Laugh-in scene where the bike topples over onto your leg, and you're going down, pinned beneath.
119 Stop for gas, carefully shut off ignition and take key out (to unlock tank), carefully remove helmet and set it over mirror, carefully remove gloves and place on instruments, open jacket, step off bike ... forgetting to put sidestand down.
120 With bike off, try to make walking U-turn in driveway. Bike doesn't have necessary turning radius, front wheel leaves pavement and goes into soft dirt.
121 The setting: Bikes at inside end of driveway, on centerstands, facing away from front of driveway. Backing cage into driveway ... slowly ... at about the right point, stop ... note that cover on bike #1 is moving slightly ... notice bike #1 ever-so-slowly roll forward off its centerstand, then sideways into bike #2. Bike #2 stands there and takes it without falling ... but there's no way to get it to lift #1.
122 Tweaking the front brake at a light as you JUST come to a stop with the forks turned to either side at ALL on a top-heavy bike.
123 Jump an old dirt bike over your parents' fence (use a rramp to get enough height). Realize on the way down that you *don't* know how to land. (I believe this was caused by "Adolescent Invincibility Syndrome".)
124 Test-ride an Electra Glide Sport (OK, these days it would have to be a Road King) around the old, cracked pavement in Brisbane near the Cow Palace.
125 Have a BMW with the sidestand linked to the clutch lever, so that pulling in the clutch retracts the stand.
126 Put the bike back together after waiting months since the last crash for a part to arrive, and don't install fuel filters. Gas tank rust clogs carburetor float needles, overflow tubes lube rear tire, brake to avoid manhole cover in curve, the waited-for part is broken.
127 Park next to some %$#@ on a Triumph who leaves his disc lock on, and return to find your XV1100 with a few dents and a little note saying 'Sorry' in the brake lever. (I left my phone number too...)
128 While riding home the day after getting your shiny new bike turn onto a dirt road and discover that they are in the process of combing the road and your front tire is now sliding through four inches of loose wet sand (Did I mention it was raining). While picking up your bike be sure to grind plenty of sand into the tank.


HOW TO HANDLE THE FALL


Assuming It's Inevitable
By James R. Davis




Of all the Tips I have posted here, this one is clearly the least credible in the sense that I have no experience in the matter, nor can I imagine a way to practice that makes any sense to me (nor would I want to.)

Still, I will post the thoughts in the hope that the reader will not take them as advice, but purely my opinions on the matter. Further, I suspect that in real life one does not have time to do anything deliberate until after the first impact, and then there may be no decisions possible. On the other hand, since I have personally witnessed a deliberate and life-saving maneuver by a woman who had just suffered a highside accident, I know that at least some people retain enough presence of mind in an accident that the following couple of ideas just might help.

The objective should always be NOT to fall - even if the bike is going down. That is why I teach my friends how to dismount their bikes (at slow speeds) if it is dumping, or to stay with it until after first impact at higher speeds, if possible.

DO NOT TRY TO BREAK YOUR FALL WITH YOUR HANDS!!! In other words, try to impact with as much of your body at the same time as possible.

If you are doing a lowside the bike is ahead of you and you want it to stay that way. Since the coefficient of friction between you and the ground/asphalt is higher than of a metal motorcycle, you want to get as much of your body on the ground at the same time as you can to slow you as quickly as possible so the bike will slide away from you. In other words, arms over head, feet first, butt down. Stay LOOSE (relaxed, in as large a configuration as possible.) LET GO OF THE MOTORCYCLE AS SOON AS POSSIBLE!!!

If you are doing a highside you will be in front of the bike when you hit the ground. You want to move as fast as possible - in the same direction you were going and for as long as you can - in order to try to avoid getting crushed. In other words, you want to 'tuck' and roll as soon as you can after you hit the ground. Stay TIGHT (in as small a configuration as possible.)


Before you try to get up after taking a spill you must be sure that you have come to a stop first! Wait a couple of seconds until you are sure.

I don't think most people will have time to do anything deliberate at all by way of falling. But perhaps I'm wrong and the above thoughts can in some way be of assistance.
---
Following the posting of this Tip I received many e-mail messages which argued that a person simply does not have time to do anything that could affect the outcome of a fall. I responded with the following:

My comments had very little to do with how you hit the ground following a 'get off' as I don't think there is sufficient time to do anything very deliberate until after the first impact, and then there may be no decisions possible. Rather, I was trying to suggest that as you are coming to rest (assuming you can function at all) then you should try to END UP either loose (as much body contact as possible with the ground) or tight (as little body contact as possible with the ground - tuck and roll posture) depending on if you went down on the low side or the highside.

Despite the fact that I don't think most people would have either the time nor the presence of mind to do much 'thinking' during a 'get off', some do. I have personally seen, for example, a woman in her late fifties do a 50 MPH highside and when she landed, because (I believe - she can't remember) she was so afraid that the bike would land on top of her, began a rapid rolling maneuver that saved her life (the motorcycle stopped 1 foot short of where she did.) I have personally witnessed this same woman (honest) respond to a huge wind gust that knocked her bike over just as we were coming to a stop at a pullout on the top of a mountain and she was thrown over her bike, this time at about 5 MPH. During this latter 'highside' she actually did a summersault before hitting the ground - a clearly deliberate move on her part (we all watched as she tucked her head down and 'kicked' away from her bike which allowed her to land on her curved back and then she 'unwound' and stopped her roll by spreading her legs. (She had gotten away from the bike that was following her, but wanted to stop rather than keep going.) Good thing, because had she gone another five feet she would have had a SEVENTY FOOT fall off the mountain. (There was no fence or guard rail that would have stopped it.) Incidentally, Elaine saw both of these 'highsides' , too.

Anyway, I mention these events because they left a very strong impression on me that some people DO have the presence of mind to determine how to END a fall, despite how fast things are happening to them. I'm not at all sure I'm one of those people, but at least I have thought about it and know that if I'm in front of my motorcycle I want to keep moving until I can't move any more - and I want as small an exposed profile as possible, just in case that bike catches up with me.

As to the lowside concept of trying to end up on your back, arms over your head, feet first - this was originally told to me by a motorcycle 'stunt man' in LA a couple of decades ago about how he tries to stop after a dismount. (Not that any of us are into that sort of thing, of course. <G>)



COUNTER-STEERING

By James R. Davis




Everyone who has driven a motorcycle has experienced it, the MSF classes mention (but don't explain) it, and motorcyclists discuss it all the time. But what is it, really? How does it work? Why does it work? All questions I will try to deal with in this discussion.

At very slow speeds we steer a motorcycle by turning the handlebar in the direction we wish to go. We can only do that at speeds of less than about 5 MPH. At any higher speed we do the exact opposite, whether we realize it or not. For example, assuming we want to turn to the right, we actually TRY to turn the handlebar left. This results in the front wheel leaning to the right and, as a result of the lean of the wheel, a turn to the right. This is counter-steering.

Why is it that we don't get confused regardless of our speed? Because we have learned that steering a motorcycle is an effortless chore. That attempt to turn the handlebar to the left FEELS like we are pushing the right grip rather than pulling on the left one. It feels like that because the harder we push it, the more the motorcycle turns to the right and, thus, it feels like the right grip is pushing back at you that much harder. In other words, we quickly learn to associate counter-steering feedback with the hand closest to the direction in which we wish to turn. Further, even a little bit of experience shows that counter-steering is essentially effortless while trying to turn the handlebar in the direction you want to go is virtually impossible. Humans are relatively fast studies, after all.

It takes only a modest familiarity with a gyroscope to understand counter-steering - at least to understand how most people believe it starts to work. The phenomenon is called Gyroscopic Precession. This is what happens when a lateral force is applied to the axis of a spinning gyroscope. The spinning gyroscope translates the force vector ninety degrees off the direction of spin. Thus, if we try to turn our front wheel to the left, the force we use appears as a lateral force forward against the axle on the right side and this is translated into a force that tries to lean the wheel to the right. Similarly, trying to turn the wheel to the right results in the wheel trying to lean to the left.

But gyroscopic precession is not a necessary component of counter-steering. No matter how slight, if your front wheel deviates from a straight path your motorcycle will begin to lean in the opposite direction. It is entirely accurate to assume that even without gyroscopic precession, the act of steering the front wheel out from under the bike would start counter-steering in the opposite direction. This is a result of steering geometry - rake. You can observe it at a complete stop. Just turn your handlebars in one direction and you will see that your bike leans in the opposite direction as a result.

In the case of a motorcycle, your handlebar input is immediately translated by gyroscopic precession into a lean in the opposite direction. Since your front wheel is attached to the bike's frame, the body of the bike also attempts to lean. It is the lean of the BIKE that overwhelms the handlebar effort and drags the front wheel over with it - gyroscopic precession merely starts the process and soon becomes inconsequential in the outcome.

If, for example, you had a ski rather than a front wheel, the front would actually begin to turn in the direction of handlebar input (just like it does with a wheel instead of a ski) and body lean in the opposite direction would then overwhelm that ski making counter-steering still effective.

The ONLY WAY to turn a motorcycle that is moving faster than you can walk is by leaning it (if it only has two wheels). We have talked only about what starts that lean to take place. Indeed, all we have talked about is the directional change of the front wheel along with the simultaneous lean of the bike, both in the opposite direction signaled by handlebar input. So then what happens?

Before getting into what is actually somewhat complicated let me say that if you were to let go of your handlebars and provide no steering information whatever (or you were to get knocked off your motorcycle), after some wildly exciting swings from side to side your motorcycle would 'find' a straight course to travel in and would stabilize itself on that course, straight up! That's right, your motorcycle has a self-correcting design built into it - known as its Steering Geometry - that causes it to automatically compensate for all forms of leaning and speed changes and end up standing straight up, going in a straight line, whether you are on the bike or not - until it is traveling so slowly that it will fall down.

This diagram shows a typical motorcycle front-end. The handlebars are connected to the steering column, which is connected to the knee bone, which is... Oops, wrong discussion. The steering column (actually called the 'steering stem') does not connect to the knee bone, nor does it connect directly to your forks! Instead, it connects to what is known as the triple-tree (shown as D in the diagram.) This is merely where both forks are tied, along with the steering stem, to the bike's frame. You will notice that the triple-tree extends towards the front and that as a result the forks are offset forward some distance from the steering stem. (Notice the red diagonal lines marked C and C'.) This is known as the offset.

Now please notice that the forks are not pointing straight down from the triple-tree, but are instead at an angle. This angle is known as the rake. Were it not for that rake (and modest offset) the front tire would touch the ground at point A. (Most rake angles are approximately 30 degrees.)

What the rake does for you is profoundly important. For one thing, it causes any lean of the wheel to be translated into a turn of the wheel towards that lean. For another, it slows down your steering. That is, if you turn your handlebar 20 degrees at slow speed your course will change something less than 20 degrees. [At higher speeds you NEVER would turn your handlebars 20 degrees - the front wheel is always pointing virtually straight ahead.] Rake, in the case of higher speed turning then really does SLOW DOWN the realization of the turn. (We will see why soon.)

Looking at the diagram, imagine that instead of pointing to the right the wheel is pointing straight at you. (The body of the motorcycle remains pointing to the right.) You will now recognize that the contact patch which was B before the wheel turned has now got to be near where C' is at. In other words, the fact that your wheel is on a rake results in the consumption of part of your steering input into a displacement of the contact patch of the wheel. (This is why steering is 'slower' - and the greater the rake, the slower it is. Note that 'slow steering' is NOT the same as 'under-steer'.)

Notice also that where the red diagonal line marked C' touches the tire is higher than where B touches the tire. This demonstrates that a consequence of turning is that the front-end of your motorcycle actually lowers based on rake geometry. The distance between where B and C (not C') touch the ground is called trail. The more extreme the rake angle, and the shorter the offset, the longer the trail is. Some motorcycles will have the hub of the front wheel either above or below the forks rather than directly in the middle of them. In effect, these placements are designed to reduce or increase the effect of the offset in order to increase or reduce trail.

The stability of your motorcycle at speed is a function of how long its trail is. However, have you ever noticed that the front wheel on bikes that have excessive rakes (and therefore long trail) have a tendency to flop over (at low speeds) when they are not aligned perfectly straight ahead? This is the phenomena that explains just one of the reasons why your wheel actually turns in the direction you want to go after it begins to lean in that direction. Any lean whatever of the wheel, because gravity tries to lower the front-end, receives an assist from gravity in its efforts to move the contact patch forward along the trail. Further, notice that the pivot axis of your forks is along C, not C' and that this is behind the bulk of the front-end. Thus, gravity plays an even bigger role in causing the wheel to turn than at first glance it would appear. (And now you see why you have steering dampers - so that a little lean doesn't result in a FAST tank-slapping fall of the wheel in the direction of the lean.)

But there is another, more powerful, reason that the lean is translated into a turn - Camber Thrust. Unlike automobile tires, your motorcycle rides on tires that are rounded instead of flat from side to side. When you are riding vertically your contact patch is right in the middle of the tire, at its farthest point from the hub of the wheel. When you are leaning you are riding on a part of the tire that is closer to the hub of the wheel. The farthest parts of the tire from the hub of the wheel are TURNING FASTER than any part closer to that hub. Thus, when you are leaning the outside edge of the contact patch is moving faster than is the inside edge.

Imagine taking two tapered drinking glasses and putting them together as in the next diagram. Does this not bear a striking resemblance to the profile of your tires when looking at them head on?



Now imagine placing one of those glasses on its side on the table and giving it a push. Note that the glass MUST move in a circle because the lip of the glass is moving faster than any other part of it. The same is true of your tires. This camber thrust forces your wheel to turn in response to a lean.

Thus, both the rake geometry and camber thrust conspire to cause a leaning front wheel to become a turn in the direction of the lean. Then, of course, the motorcycle body follows the wheel and it, too, leans in the direction of the turn.

So, now you know what counter-steering is, how it works, and why. What might just now be occurring to you is with all of these forces conspiring to cause the wheel to lean and then turn in the direction you want to go, what stops that wheel from going all the way to a stop every time a little counter-steer is used? And, as I earlier mentioned, how does a pilotless motorcycle automatically right itself?

The answer to both of those questions is centrifugal force and, again, rake geometry. For any given speed and lean combination there is only one diameter of a circle that can be maintained. This is a natural balance point at which gravity is trying to pull the bike down and centrifugal force is trying to stand it up, both with equal results. (If you have Excel on your system you might want to click on this link for a model that demonstrates this concept.)

If the speed is increased without a corresponding decrease in the diameter of the turn being made, centrifugal force will try to stand the bike more vertically - i.e., decreases the lean angle. This, in turn, decreases the camber thrust and the bike will, of its own accord, increase the diameter of the turn being made.

If the speed had been held constant but the bike attempts to shorten the diameter of the turn beyond that natural balance point then centrifugal forces are greater than gravity and it stands taller, again lengthening the diameter of the turn as described earlier.

Once your bike is stable in a curve (constant speed and constant lean) then it will stay that way until it receives some steering input. i.e., you again use some counter-steering or the road surface changes or the wind changes or you shift your weight in some way or you change speed.

As soon as any form of steering input occurs the stability of the bike is diminished. Momentum, camber forces and rake geometry will then engage in mortal combat with each other which will, eventually, cause the motorcycle to find a way to straighten itself out. That momentum will try to keep the motorcycle going in a straight line is obvious, but it also works with traction in an interesting way. That is, because the front tire's contact patch has traction the momentum of the entire motorcycle is applied to the task of trying to 'scrub' the rubber off that tire. If the body of the motorcycle is aligned with the front tire (only possible if traveling in a straight line) then there is essentially no 'scrubbing' going on. But if the bike is not in perfect alignment with the front tire, then momentum will try to straighten the wheel by pushing against the edge of that contact patch which is on the outside of the curve. As the contact patch touches the ground somewhere near point B, and because that is significantly behind the pivot axis of the front-end (red-dashed line C), the wheel is forced to pivot away from the curve.

I believe you now see why if the bike were to become pilotless it would wildly gyrate for a few moments as all of these conflicting forces battled each other and the bike became stable by seeking a straight path and being vertical. Clever, these motorcycle front-end designers. No?