How would you go about laying your bike down?

[askmrjesus]

From the online DMV manual:

"When faced with a potentially dangerous situation, it's generally best to remain upright on your bike. Remember, tire rubber has an immense amount of traction. However, plastic, steel, and chrome (the materials found on the side of the bike) offer almost no traction. When you stay on your motorcycle instead of letting it slide, you'll be better able to stop in time or swerve out of the way. The only possible time where it might be a better idea to purposely end up on the ground is when it's better than the alternative, like going over a guardrail down a cliff or into the middle of a ten-car pile-up. Once you lay down a bike, you have absolutely no control over where you will end up."

This is pretty much what I've been saying all along.

JC

[karl_1052]

Originally Posted by askmrjesus

From the online DMV manual:

"When faced with a potentially dangerous situation, it's generally best to remain upright on your bike. Remember, tire rubber has an immense amount of traction. However, plastic, steel, and chrome (the materials found on the side of the bike) offer almost no traction. When you stay on your motorcycle instead of letting it slide, you'll be better able to stop in time or swerve out of the way. The only possible time where it might be a better idea to purposely end up on the ground is when it's better than the alternative, like going over a guardrail down a cliff or into the middle of a ten-car pile-up. Once you lay down a bike, you have absolutely no control over where you will end up."

This is pretty much what I've been saying all along.

JC

You didn't just quote the DMV on anything related to knowledge, did you?
The same DMV that will issue licences to 98 year olds who drive through crowded markets killing people? Yeah, I would trust their safety knowledge.

BTW, that quote was probably written before disc brakes were invented.

[askmrjesus]

Originally Posted by karl_1052

You didn't just quote the DMV on anything related to knowledge, did you?
The same DMV that will issue licences to 98 year olds who drive through crowded markets killing people? Yeah, I would trust their safety knowledge.

BTW, that quote was probably written before disc brakes were invented.

Would you prefer an MSF instructor?


High Side Dynamics
By James R. Davis


More often than not, making a mistake while riding a motorcycle leads to misfortune, usually not serious, but sometimes fatal. One of the most deadly mistakes you can make is called doing a highside.

When a bike is 'dumped', or 'laid down', it falls DOWN, gravity assisted, all the way to the ground and ends up on its side. At slow speeds this usually results in little or no damage to the bike or the rider. Even at higher speeds, given that the rider is wearing appropriate protective clothing, most damage is restricted to the bike. In either case, these are known as doing a lowside - meaning that the rider exits the bike by going in the direction of the fall: down.

Obviously, doing a highside means that you exit the bike by being thrown up and over the high side of the bike. That, in itself, is not particularly deadly, but it happens that the bike usually follows the rider into the air and then it comes back down, often on top of him. Not too many people survive such an encounter.

So how does a highside happen? What causes it and what can you do to prevent it from happening?

To begin with, a highside starts when you use so much rear brake pressure that you lock your rear wheel. If you are in a curve, (or if you have also applied your front brake while going in a straight line, or if there is substantial road camber, or severely unbalanced loading of the motorcycle), this starts the rear end sliding/skewing away from the direction the bike had been moving because traction is diminished on the rear tire (it has become 'sliding friction' - about 80% of what it was just prior to the skid) and that tire has begun to MOVE FASTER (in the direction of bike movement) than the front tire (centrifugal force, among others, is having its way.) The automatic, and correct, driver response to this situation is to turn the front wheel in the direction of the slide. [Actually, the front wheel will turn in the direction of the slide by itself - your job is merely to let it.] But now he can make a mistake that can cost him his life - he can release the rear brake.

Let's look at what is happening at the instant his rear brake locks up causing his rear wheel to begin to slide and the instant that he releases pressure on the rear brake. Let's assume a rider is in a gentle turn at the time. (Riding in a straight line is exactly the same as soon as the rear wheel starts to skew to one side or the other of the front wheel track.) The bike is moving in the direction pointed to by the front tire at this instant. Note that the back tire is always 'scuffing' a little as it tries to get into the same direction pointed to by the front tire.

Now at this instant the rear brake locks and the rear wheel loses a significant amount of its traction (at least 20%). It begins to skew outward from the center of the curve.

The driver now allows the front wheel to turn in the direction of the slide. The direction of bike travel has thus changed. Meanwhile, the rear end continues to slide and is still moving FASTER than the front end at this instant. The bike is trying to 'lay down' [because with the rear-wheel no longer spinning you have lost its gyroscopic effect and, thus, attitude stability for about 80% of the bike] and will do so if nothing else happens quickly.

But the rider, realizing that his rear end is sliding completely out of control, decides to release the pressure on the rear brake to try to drive out of the situation. When he does so the rear tire, which is being dragged forward as well as to the side, is suddenly able to start turning again. This allows it to move in the forward direction much more easily than a moment before, and just as suddenly it regains traction (mind you, it lost only about 20% of its traction when it began to slide and it is picking up only that 20% or so of traction at this point.)

Whether the engine is driving the rear tire or not, because the bike is not simply 'dragging/scuffing' the rear tire forward with it (because the tire is now rotating), the bike begins to move faster (actually, is slowing more slowly) in the direction pointed to by the front tire. At the same time, because full traction has been regained, the sliding movement of the rear end of the bike comes to an abrupt end. And what next happens is the highside!

Whether the slide movement of the rear end is abruptly stopped because the rear wheel hits a curb, or because the tire has regained traction, the results are the same: centrifugal force, coupled with inertia, try to keep the center of gravity of the bike moving in the direction it was last traveling. Since the bottom of the rear wheel has stopped sliding, (all stopping forces are at the contact patch), clearly a torque is developed. The result is that the bike is violently twisted in the direction of the earlier slide. The front wheel actually helps this twisting action because it has a bearing in its axle and the bike merely rotates using that bearing as an axis. Naturally, the driver will be thrown in the same direction as the bike is twisted. The mistake, of course, was releasing the pressure on the rear brake. Said differently, if you are in a situation where the rear wheel is sliding out from under you, despite having turned the front wheel in the direction of the slide, then the safest course of action is to RIDE THE BIKE INTO THE GROUND - do a lowside. (i.e., do NOT release the pressure on the rear brake.)

Let me also add that there is one more thing that could have been done to avoid the highside described here: always straighten the bike BEFORE you aggressively use your brakes when in a curve!

If the bike is moving in a straight line, particularly if the bike has any form of integrated braking, and the rear wheel brake locks resulting in a skid, it is still possible to do a highside, but the odds of doing so are far less than when in a curve [the faster you are moving, and the greater the camber (slope) of the road, the higher the odds.] Still, the best decision the rider can make is to NOT RELEASE the rear brake if it is locked to try to insure that a highside does not result.

Abruptly releasing the front brake when the rear wheel is locked and skidding can also cause a highside because it will increase rear wheel weight and, therefore, traction. Nevertheless, the only possible way to 'ride out' of this situation is to get the front end of the bike to go faster than the rear in the direction of the skid. Thus, a gentle relaxation of the front brake is a reasonable action to take. (Note, however, that with any form of integrated braking, this is virtually hopeless because so long as the rear brake is applied the front brake is also being applied.) Increasing front brake pressure, on the other hand, will almost certainly result in immediately laying the bike down on the low side.

Can a highside occur if you do not release the rear brake pressure at all? You bet! If you have ever witnessed a 'straight line' highside accident you will remember that the skid mark was a straight line until the very end at which point it became a 'J'. What that shows is that the rider successfully managed to keep his front wheel pointed in the direction of the skid until he had turned his wheel to its limit (a 'stop' was reached.) When that happens, of course, he can no longer continue to turn into the skid and the direction the bike travels begins to abruptly change - the skid increases until it presents a 90 degree tire face in the direction the bike is moving, which happens to present the largest contact patch 'face' perpendicular to direction of travel and, thus, maximizes the odds that traction can be reestablished. This, then, is approximately when the bike stops its skid and violently snaps into the air.

Having seen that a rear end skid requires that you gently relax front brake pressure and maintain rear brake pressure in hopes that the front wheel can be coaxed into catching up with the rear one (slow more slowly), what should you do if the front wheel begins to skid instead of the rear one? EXACTLY THE SAME THING! Gently release the front brake and maintain the rear one! Thus, you do not have to make a decision based on which tire is skidding. The reaction is the same. So, above I said that if you have a choice you should ride the bike into the ground rather than do a highside. I also said that the dynamics will almost certainly result in a highside even if you do what is corrective - turning into the slide and feathering the front brake. Is it hopeless? Must you do the highside? Not at all. It means that as soon as you know the attempt you are making is not going to work, CLIMB ON THE FRONT BRAKE! This will FORCE a lowside!!! (If you have any form of interlocked brakes you can also force a lowside by INCREASING rear-brake pressure because that increases front-brake pressure as well.)

Please, I do not want to get flamed for suggesting that you actively lowside your bike! If you have ever seen the results of a highside, you should kiss the ground that you have the ability to stop it by laying your bike down. If you can do it, do it. If not, good luck to you anyway. [I have been asked why aggressively using the front brake will cause a lowside rather than making a highside happen sooner. This is because by applying front brake you cause weight transfer that further relieves the rear wheel traction which, in turn, both reduces the odds of a highside and slows the bike faster. i.e., it falls over (lowsides) sooner.


Never say never.

JC

[pauldun170]

If I were to go about laying my bike down.
I would first drain the fluids.
Remove the plastics.
Choose which side I'm going to lay it down on and remove any peices that may bend.
I would the lay out 10 deluxe medium soft pillows, slightly overlapping on the floor where I'd lay the bike down.

I'd lay the bike down on the pillows.

What happens next...depends on the wine and music

[Homeslice]

lol......let the google-searching wars commence

[Tmall]

I would like to take this moment to point out that racer x is an msf instructor.


Would you change your mind if he agreed with us?


Besides, you're not even arguing a point anymore amj. You're trying to get by on semantics.


I told you earlier that I understood where you're coming from.


If there's a cable across the road at chest height, of course ill lay the bike down. That makes the most sense. Nobody ever once argued that.

You just failed to acknowledg what everybody else was saying and seem like you'd rather be right, than on topic.


Keep at it, but there's no situation when you're going to hit a large immovable object that laying it down is the best scenario..

[askmrjesus]

Originally Posted by Tmall

I would like to take this moment to point out that racer x is an msf instructor.


Would you change your mind if he agreed with us?

If Ed had a better way to get out of a highside, sure.

Originally Posted by Tmall

Besides, you're not even arguing a point anymore amj. You're trying to get by on semantics.

I told you earlier that I understood where you're coming from.


If there's a cable across the road at chest height, of course ill lay the bike down. That makes the most sense. Nobody ever once argued that.

You just failed to acknowledg what everybody else was saying and seem like you'd rather be right, than on topic.


Keep at it, but there's no situation when you're going to hit a large immovable object that laying it down is the best scenario..

So small immovable objects (cables) is a go.

Good, that is my point. There are some instances, though rare, that laying the bike down is a good idea. See that? We're making progress. Everyone else seems to be saying NEVER NEVER NEVER, but you just proved that there are no absolutes.

I knew you'd see it my way.

JC

[dReWpY]

i wouldnt

[Tmall]

Originally Posted by askmrjesus

If Ed had a better way to get out of a highside, sure.




So small immovable objects (cables) is a go.

Good, that is my point. There are some instances, though rare, that laying the bike down is a good idea. See that? We're making progress. Everyone else seems to be saying NEVER NEVER NEVER, but you just proved that there are no absolutes.

I knew you'd see it my way.

JC

Dude, seriously...

Originally Posted by Tmall

I don't like your options, how about 35mph without a bike or 5 mph with one?


I undertand what you're saying amj, fully.

But! You will always stop faster while one the bike on the brakes, as opposed to sliding on your ass.


I've looped a bike at 60mph and slid and rolled at least 75 to 100 feet. I could have stopped using my brakes in 1/4 of that.


The bike would have slid much further, but it got stopped by some trees.

[pauldun170]

So...next time I'm faced with
a. limbo bar
b. cable strewn across the r


wait a minute...how thick a cable? What diameter cable are we talking about?
Too thin...you wont have time do all this fancy laying it down stuff.
Too thick and why not just stop the damn bike?

What about height?
If its low enough to hit the fairing...it could just kinds deflect over if you lean down enough...

If its to low then you'll do a high side.