What causes unintentional tail-whip

I used to have that happen to me. Landing sidways like that is one of the worst feelings, worsened by the fact that you know its going to slingshot hard to the other side after you land it (If you land it). It didn't matter what I did to the shock or how I how I hit the jump face - right side, left side, over the front of the bike or hanging off of the back, weighting the right peg or the left peg or even weight perfectly lined up, you name it and I tried it. It would normally occur on faster jumps where I was carrying alot of speed and it always drifted to the right. What cured it for me was ignoring the chain alignment marks on my swingarm. One day I just noticed my sprocket wear was really bad on the inside, but the marks showed that it was aligned. I decided to just align everything by eyeballing it and just trying it to see if it helped even out the sprocket wear...Well, it did, and as a side benefit it fly's as straight as an arrow now unless I really screw up on the jump face. I now use an alignment tool for total accuracy. Your shock could be off as sugested above but I would start resolving this by rechecking your alignment so that there is no doubt of alignment and then go on to the shock if your flight does'nt improve. Messing with the shock can get confusing and time consuming sometimes. Good luck, I know how you feel.

Grashoper; You illustrate a good point. However, there are simple low-cost tools that make wheel alignment quick and easy. One such tool clamps to the rear sprocket with a sighting arm that the mechanic uses to sight(aim) for accuracy. It works well. Once alignment is assured and the rear wheel still tends to kick to one side or the other, another tack needs to be explored. An over-active rebound setting on the shock can make the rear wheel feel "nervous" on certain jump launches. This phenomenom usually manifests itself on jump faces that are tall or long ...or the surface is loose and the rider can't use body English to absorb rebound. Seat-bounce take-offs also contribute to this problem if traction is iffy.....as in deep ruts or sandy faces. These faces are hard enough without the added twitchy feel of a rear suspension that has too much of an active rebound.

The rebound has alot to do with it

Bottom line is

If you good like Me (See Egos Best Side)

You dont care where the tail is as long as the front is pointed in the right direction :)

Everyone here has solid replys and suggestions,

I do think that is a combination of them all

Proper Aligmnet, setup in rebpund dampning etc etc. It also has to do with ability and skill,

Face it the bike is going to skip jump whip bounce all over the place the harder you ride it and the more HP (Throttle ) you apply. Geez man ya got a beast that is simply just trying to run, thats what it is designed to do.

[ June 08, 2002: Message edited by: EgoAhole ]

I am coming off of a knee injury and noticed this problem. After some thought I reasoned that I was protecting my previously injured leg slightly before the landing impact. A good clue was that it always drifted to the same side.

This is caused when the rear of the bike is moving faster than the front of the bike.

I always thought this to be the case as well.

>> if the front end is plowing (sand/mud) and the rear is spinning, the rear IS going faster that the front.

Body positioning, gripping the tank w/ knees all fall into play here.

I had this problem when I first got my bike. I couldn't keep it straight for nuthin. I tried working on my balance, my geering to change RPM for approaches, watching vidoes, everything. Then I went through my suspension with a fine tooth comb and finally fixed the pitch-out problem by taking out a bunch of pre-load on the shock spring. This is a huge spring (check the suspension charts and this spring is used for a wide range of weight).

For some reason my bike seems to want to fly too far now... :)

Ragdoll Racer

00 426 with lots of goodies.

Causes of unintentional tail whip: Staying out late with the boys, buying that extra part for your bike, getting caught at the bar with your neighbor's wife. . . Ouch! :)

I just experienced this today....mine was due to being in First Gear on jump I would normally be in third gear on. Too much wheel spin (throttle bliping) makes the rear end wnat to go some where once it gets in the air. If all things are not "perfect" (i.e. no kicker, perfectly straight, etc.) physics is going to want to take you wherever the most force is being applied. Grip the tank tight with your knees...be ready for the landing (on the gas/absorbing with your arms/legs, etc.) and you can ride out a lot of stuff that might crash the "average" dude.

I've found that the more actively I jump the bike, rather than just sitting there to see what happens, the more control I have and the more it does what I want. That is to say, when I unweight the pegs and bunny hop or give it some body english to whip the back out a little, it pretty much does what I want every time. If I just slam the jump and see what happens, sometimes I'm unpleasantly surprised.

That said, I think a combination of the suggestions should fix it - measure wheel alignment instead of relying on the marks, be sure the bike is straight up and down when you go off the jump and not leaned, too little rebound will magnify any minor problem by making the back end kick worse instead of being forgiving, and be sure to unweight both pegs equally when you launch. It helps to be in the "attack position" with your elbows up when you hit the jump; if you're not, you may have one up and one down which reflects unequal weighting of the bike and will make it drift sideways. Speaking of which, when you say "tail whip", does it drift sideways or kick sideways? Drift is likely to be body position; kick is likely to be body position plus suspension settings (too much preload, too little rebound damping).

Last suggestion: go off jumps with some throttle, not chopped. Chopped throttle also seems to magnify minor errors. Of course, too much throttle causes wheel spin or loop outs.

And if it is sideways when you're landing, more throttle is better. If there is good traction and you front wheel isn't too high already, pin the throttle. Don't do that if your front end is too high or poor traction.

If you keep having this problem, at least get someone to take some pictures or a movie. I wish I had more pictures of my best (worst?) crashes! :)

Good luck!

Poor rear wheel alignment causing the rear end to whip out??!!

Umm...NO!

A misaligned rear wheel WILL cause the rear to swing around instead of fly straight. Other causes might be incorrect rebound, a rut, or wheel-spin.

By saying it cannot possibly be the cause, without watching him ride and seeing it first-hand, you are spreading misinformation.

Try this:

Set your sag

Click up on the Compression two or three clicks.

Leave the rebound.

In my experience if you think you are going straight when you are hitting a jump, chances are your right and your setup is off.

A misaligned rear wheel WILL cause the rear to swing around instead of fly straight. Other causes might be incorrect rebound, a rut, or wheel-spin.

By saying it cannot possibly be the cause, without watching him ride and seeing it first-hand, you are spreading misinformation.

Right on skthom2330! I had a ploblem with this on my 450. Try measuring from the centerline of the rear axle bolt to the centerline of the swingarm bolt. You might be surprised! I did this and my marks on the axle blocks were lined up, but the distance between these two bolts was off 1/8inch! that meant that at my rim 1/2" or more crooked :D , this can cause some serious problems :D:) never rely on those crappy marks on the swingarm. Your wheel axle should always be parallel with the swingarm bolt, otherwise the bike WILL kick. Because if the rear wheel is crooked, then as soon as your front wheel leaves the jump then the rear wheel will try to straighten out due to centrifugal or gyro force, in turn steering itself.

I am not saying this is the SOLE problem with yours but I would check it out. :) It may have something to do with it.

Ahhh, you got me again with a 3 year old post. :) I thought 'yznvegas' was back :)

the angle you approach the jump ... throttle control when you leave the face ... if your rebound/compression settings on your shock are out of wack ... those 3 things can contribute to rear end trying to pass you in the air ...

Alright! ...who woke up this dinosaur??

I'm embarrassed... :applause::eek::)

Everyone has hit all possible reasons for kick out, i.e. misalignment of rear sprocket, rebound, sag, jump alignment. Once you take all of the possible solutions, and work them into what you are doing, what you have checked, or what you have fixed, you can start eliminating them one by one.

Personally, 2 weeks ago, I did the mark alignment for the rear sprocket. Not a common practice for me, cause I know they arent accurate, but I didnt feel like getting out my tape measure, cause my buddies we chopping to hit the track. Sure enough, over the 80ft table, and the rear is drifting out. I knew exactly what it was. I got back and pulled out the tape measure and measured from the end of the swingarm to the adjusting block, and I was off by almost 2 turns on the right side. After that was fixed, the bike didnt drift to the right anymore.

On that note, in regards to the rebound, and the rear wheel spinning faster than the front. If you think about jump take off, and if you are not squared to the jump face, your rear end will tend to drift opposite of the way your leaning. In some cases, most of us correct this without knowing or realizing we do it, but when we tend to get outside of our abilities, natural instinct doesnt know how to compensate for it. More expierienced rides have learned how to compensate, thus the big whips that seem far from recovery. Either way you look at it, you have to take into account what everyone is saying, and use the process of elimination to determine which factor is causing your problem, whether it be jump alignment, body position, rebound, sprocket alignment, throttle, ect....

Good luck

By saying it cannot possibly be the cause, without watching him ride and seeing it first-hand, you are spreading misinformation.

Look...it's simple. The only energy source that can cause a scenario as the one described is the one is which the spring is unloading too quickly.

This is not voodoo science. It has nothing to do with rider style, ruts, drive trains or anything else that you guys can come up with.

In other words, it's not possible for the drive train or any other source other than the shock to cause the rear end of the bike to travel beyond the angle in which the rear wheel is aligned.

Got it?

Now...when you load up a 5.2 spring, for example, it pushes back with over 1400lbs. of force. When you release that much stored energy within a fraction of second, with little to no resistance, you can bet that the back end of the bike is going to launch in one direction or the other. The stored energy simply has no where else to go, and this is the type of force that it takes to cause such a movement.

Does this mean that the fix is to add more rebound damping?

Not always, but it's usually the case. I see it all the time, it's happened to me, it's a very common and dangerous problem.

However, you do need to verify that the shock is not overloading as well, but even if it was, you still can't have a shock that wants to let go like this.

Best of luck.

OK I'll throw another at you. Going around a left sweeper in 3 (yz125) hit the jump slightly leaned, back wheel always whips to the inside of the corner. It does the opposite if turning right (it whips out to the right) now my understanding of this is that it is probably the back wheel returning to quick, right. ala too much rebound!

Correct me if I'm wrong.

now my understanding of this is that it is probably the back wheel returning to quick, right. ala too much rebound!

First of all, let's clarify what we mean when we say, "too much rebound" since this has been a problem in the past.

Rebound, in this business, is almost always a reference to damping. Therefore, "rebound" means "rebound damping". Too much rebound means too much damping, which means the rear shock is not recovering fast enough. And, not enough rebound means that the rear end of the bike is releasing too fast or kicking.

To add rebound, you turn the screw in, or clockwise. To remove, the opposite.

Now, Ashes has brought up a good point. That is, what happens when you are leaning and jumping while progressing through a corner?

The answer is conditional, since it depends on the application of power. If the rear end has outward momentum, that momentum will continue with less resistance as soon as the bike becomes airborne. Hence it "kicks" (or travels) to the left or right, when coming out and over a left or right corner, respectively.

In these cases, the rear wheel is usually spinning, slipping or roosting when the bike becomes airborne, and in such a case rebound will do little to maintain the whip of the bike that was already under way before the ramp was hit.

I can't imagine you're on the front brake in this case, but if you were, it could make matters worse.

Make sense?

DaveJ

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