By: James R. Davis
Sooner or later you will find something in the road just ahead of you and you are going to hit it. Maybe a small animal. Possibly something that falls off of the vehicle in front of you. Maybe you have missed a curve and a curb is dead ahead.
One of the exercises taught by the MSF includes running over a board (4×4?) and you are told to ‘lift’ the front-end of your motorcycle at the last possible moment before you hit. I suspect that most of us could actually ‘lift’ the front-end of a little 125cc motorcycle, but I can tell you that this is one reasonably strong male that couldn’t raise the front-end of my GoldWing a meaningful fraction of an inch, from my seat, and neither can you. What’s the point of the exercise, then?
Maybe it was just badly explained in my particular class, but I’m sure that what the instructor said was that you are trying to ‘help’ the bike over the obstacle by lifting it. While that is correct, both the explanation and the exercise fell as short of the mark as did my ability to lift the Wing.
Remember our discussion about shock absorbers? It was learned that bumps are first absorbed by your springs and that your front-end rises and falls as allowed by how the shock absorber/spring set are designed and setup. If you are traveling at a steady speed your front-end is extended about as far as it will normally be extended and your ability to ‘lift’ it further is a function of how much weight you can remove from it, not how strong you are. That ‘for every action there is an equal and opposite reaction’ tells you that if you are able to exert 200 pounds of lift on your grips you will put the same amount of new ‘weight’ on the seat and pegs while you do it. So, even if you try to ‘snap’ lift the front while throwing as much of your body towards the rear of your bike as possible, the result will be a TRIVIAL difference in the extension of your front forks. i.e., virtually a waste of time and energy.
Still, the idea is RIGHT! But instead of you doing the lifting, you want the bike to lift itself by transferring its weight from the front to the rear wheel.
You already know that this happens naturally as a result of acceleration. So, the way you lift the front end without suffering a hernia is to twist your wrist and open the throttle.
But you will remember that your front-end is already almost fully extended to start with. Wouldn’t it be nice if you could get a whole lot more extension just before you hit that object? Well, of course the fact is that the only way to do that is if the front-end was more heavily loaded (compressed) before you started to accelerate. And how do you get the front-end to be more loaded? Why you hit the brakes, of course.
In other words, in the real world if you see that you are going to hit something you will naturally apply your brakes in an effort to slow down before you do so. Isn’t that fortunate? For in order to maintain as much control of your bike as possible WHEN you hit it all you have to do is roll-on the throttle at the very last moment (about 1/2 second will do very nicely.) This will result in a weight shift from front to rear, and allows the springs in your shock absorber system to extend.
Thus, as you hit the object you have maximum shock absorbing capacity, just when you need it. (Don’t forget to shift your weight to your pegs and get that butt off the seat when you do this since when the rear tire hits the obstacle it will receive a severe vertical bounce.)
[I suppose it is obvious, but since you are going to experience a vertical jarring of the bike and you are going to be lifting your butt off your seat just before that happens, you will want to have all of your fingers wrapped around your grips at the time – not covering any levers.]
But why not just stay on the brakes all the way, you ask? At the very least this will insure that you hit the object with the minimum of speed possible. What’s wrong with that?
The shock absorber system is compressed almost as far as it will go during hard braking. That means there is essentially no more travel left to absorb the bump. That, in turn, means that you will FEEL and be affected by that bump – just as if you didn’t have any shock absorber at all. You will remember that this means that the entire bike will rise and fall at least as much as the height of what you hit because it is no longer ‘sprung weight’. And it is just such bike motion which usually translates into loss of control!
Another, but equally important reason you do not want to have your brakes maximally applied at the time you hit the object is that you are then at, or past, the point of a skid. When you hit you will certainly pass that point and end up in a skid. It takes only a fraction of a second of front tire skid to totally lose control of your motorcycle. If you happened to be going is a straight line when you start a skid, your chance of recovering and not going down is actually pretty good. But if the skid is the result of your front-end being lifted off the ground because of hitting something, the odds that it will come down with the front wheel pointing straight ahead is not very good at all.
The third reason you do not want to be braking when you hit is that the object may well be alive and your tires will act like erasers as they go over it. Indeed, the ‘object’ you hit might even have been human (before you ‘erased’ it.)
Five things to do if you are going to run over something:
- Use maximum braking in an effort to stop before you hit it.
- Wrap all of your fingers around your grips – do not ‘cover’ any levers
- Roll-on your throttle starting about 1/2 second before the impact and shift your weight onto your feet.
- Roll-off your throttle right after the front tire surmounts the obstacle (shifts weight to front and lengthens the rear shocks).
- Control stop (if you want to) after BOTH tires return to the ground.
Copyright © 1992 – 2014 by The Master Strategy Group, all rights reserved.
(James R. Davis is a recognized expert witness in the fields of Motorcycle Safety/Dynamics.)