Rear Wheel Hop - Track Day | GTAMotorcycle.com

Rear Wheel Hop - Track Day

CDN-GTR

CDN-GTR

Well-known member
At my last track day at TMP I noticed on occasion that I would get some rear wheel hop under hard braking at the end of the front straight.

What suspension adjustment or rider adjustment is required to limit this hop from happening.

Just to note, I'm a beginner/green group rider who took the FAST level 2 course a few years back and fully remember being told not to use the rear brake so I only brake only with front. (I'm sure more advanced riders may use some rear but I currently do not).

Thanks
 
Probably caused by gear changes on downshifts. You can prevent it by either blipping the throttle with every downshift (takes skill) or by releasing the clutch very gradually (easier to do). The other option is to install a slipper clutch, which is what you would have had on the bikes at the FAST program.
 
Im assuming you're using front and rear brakes. It is very likely you are locking up the rear brake and hopping the tire.

**When you're hard on the front brakes the weight of the bike shifts forward onto the front rear causing the rear end to become light. This combined with to much rear brake will cause the tire to bounce around.
 
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CDN-GTR said:
At my last track day at TMP I noticed on occasion that I would get some rear wheel hop under hard braking at the end of the front straight.

What suspension adjustment or rider adjustment is required to limit this hop from happening.

Just to note, I'm a beginner/green group rider who took the FAST level 2 course a few years back and fully remember being told not to use the rear brake so I only brake only with front. (I'm sure more advanced riders may use some rear but I currently do not).

Thanks
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Speedy_05 said:
Im assuming you're using front and rear brakes. It is very likely you are locking up the rear brake and hopping the tire.

**When you're hard on the front brakes the weight of the bike shifts forward onto the front rear causing the rear end to become light. This combined with to much rear brake will cause the tire to bounce around.
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Nope
 
fastar1 said:
Probably caused by gear changes on downshifts. You can prevent it by either blipping the throttle with every downshift (takes skill) or by releasing the clutch very gradually (easier to do). The other option is to install a slipper clutch, which is what you would have had on the bikes at the FAST program.
Click to expand...
I have the downshift with the blipping the throttle down pat (33 years of that).
Bike has a slipper clutch set up to full slip. (It's a beautiful thing to hear and feel, compared to my other bikes)



dricked said:
What bike are you riding?
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Bike is a 1997 Kawasaki ZX7R I have rebuilt the clutch to the race spec. full slip and it works great.
 
Fastar1 has it, the answer and solution. Or just get used to it - makes riders behind very nervous when they see it.

I put a slipper clutch in this year and almost eliminated it. But I'm still super lazy with the clutch and pretty used to the feel of it so don't worry too, too much.
 
meme said:
Fastar1 has it, the answer and solution. Or just get used to it - makes riders behind very nervous when they see it.

I put a slipper clutch in this year and almost eliminated it. But I'm still super lazy with the clutch and pretty used to the feel of it so don't worry too, too much.
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Slipper clutch and the blip are there already.
 
I keep thinking it maybe in my rear or front suspension settings.
Can we look down that avenue.
 
If your lifting your rear tire and it's skimming the bumps there's not much you can do. Does the rear act abnormally anywhere else on the track? You could just end up with a badly setup shock trying to remove something that isn't a big issue. If you already have a slipper and your rev matching, try letting the clutch out slower. You still blip but don't just dump the clutch after the downshift.
 
I'm going with suspension settings. I'm prolly not describing it right but it sounds like the rear is stiff and lifting since the setting isn't quick enough to compensate for the front diving on braking therefore lifting off the ground.
 
If you're bottoming out he front suspension under braking you can get a little wacky rear end action.
 
If your braking a ways past the wall there is 2 bumps that get the rear airborne. Feels like a hopping tire.
 
I dont want to hurt any feelings but I have been to tmp lots and the only place on the tracks braking zones that have bumps that could upset the rear is 7 a/b if you hit the turtle. You are dropping the clutch too hard and whatever slipper is not able to handle it and thats causing your hop. If it was a problem with suspension your would feel it all over the track, not just on braking while downshifting.
 
Snipes20 said:
I dont want to hurt any feelings but I have been to tmp lots and the only place on the tracks braking zones that have bumps that could upset the rear is 7 a/b if you hit the turtle. You are dropping the clutch too hard and whatever slipper is not able to handle it and thats causing your hop. If it was a problem with suspension your would feel it all over the track, not just on braking while downshifting.
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Rest of the track is good.
So I'm gonna have to go with me expecting too much out of the slipper. Next outing in a couple weeks I'm gonna try releasing the clutch a bit slower see if it helps.

The skipping I was getting was under braking, especially if I felt I needed to slow a bit more just before the turn in. (Speeds kept getting faster down the front so it was happening in the later sessions.

Front suspension is not bottoming out, I may then look at the rebound on the rear shock.
 
The first thing I would do is make sure you have enough rear sag. At least 35mm with rider in full gear. Then I would start to remove rear damping two clicks at a time and see if that helps. That's a good start...

edit: just incase you are a heavy rider with a soft rear spring - you may have too much pre load on the shock. Check bike only free sag...you should have 10mm or so...
 
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stop blipping, it takes the forces off the slipper and cancelles it out, doesnt let it do its job. try this at end of the straight. down shift late but do it all at once, then throw the clutch out. no blip. see what u notice.
 
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