CHELOZ28

What causes wheel hop? The other day when my buddy decided to do some doughnuts, When I watched the video I noticed that his rear wheels looked like they were bouncing. Its a convertible lt1 6-speed, he has no clue as to why this happens on his car, is there a way to fix it?

JakeRobb

You can replace some suspension parts (lower control arms and springs/shocks have the biggest effect) to decrease wheel hop. Tire selection also plays a role.

Does he have stock suspension? What tires?

2000GTP

Most of the big names are all very similar to each other.

JakeRobb

Big name what? Tire manufacturers?

I don't expect the original poster to know which tires are similar and which are not. If he can tell me make, model, and size, I can deduce the rest and answer his question.

If you are indeed referring to tire manufacturers, then I would like to respectfully and wholeheartedly disagree with you.

Big names:
1. Michelin
2. Goodyear
3. BFGoodrich
4. Firestone
5. Cooper
6. Toyo
7. Yokohama

I'm sure I missed some, but those are all definitely big names. But the tires from each of those vary greatly. For instance, Michelin and Gooyear have wet handling down to a science, while that particular characteristic is Cooper's main shortcoming (this coming straight from a Cooper tire engineer that went to school with me).

Mickey Thompson (a division of Cooper) knows how to build a tire for great straight-line traction, and great rock/sand/mud traction too, but I'd never buy a Mickey for autocrossing.

Yokohama and Toyo have the dynamics of small cars (Civics, etc) figured out, but as the weight of the car goes up, they start to lose their effectiveness. I don't know the details, but I know that I'd never put a 3400-lb F-body on a Yokohama tire, but that's the first thing I'd consider for a sub-3000-lb Civic.

So yeah, go ahead and tell me again that all the big names are the same.

And if you weren't talking about tires, I apologize for my little soapbox rant.

2000GTP

No, I was referring to the lower control arms, I should have been more clear I guess.

2000GTP

I got my head in the clouds, my post was actually directed to the "lower control arm" thread. I don't know how I ended up posting my response in here. Guess I need a coffee break.

dippinZ28

i have a 96 lt1 convertable 6spd...its lowered....with stock suspension except springs and shocks...but i wouldnt know what kind they are...guy before me did this...but im wondering why it does the wheels hop...it did it during doughnuts and an attempt to race..on take off..any help? i have brand new falken GRB tires 285-35-18

teke184

lowering the car throws the rear suspension geometry out of wack. basically the LCAs don't have the proper angle to prevent the axle from twisting or rotating under load...causing wheelhop.

single best mod to help fix (may not totally cure it) would be relocation brackets. they will allow the back mounting location of the LCA to be lower, restoring (and actually improving) the geometry.

the 2nd best upgrade after that would be some good lower control arms. the bushings will be stiffer and the actual arm will be stiffer allowing less flex under load. these two combined will probably eliminate wheelhop completely.

teke184

a good thread with pics


just do a search for "brackets" in the suspension forum...you'll get plenty of hits

JakeRobb

Yup, lowering a car without adjusting everything else is going to give you wheelhop.

I have never tried Falken tires. They work great on my friend's modded WRX, but dynamically that is a very different car. Let's put it this way: the more expensive tires are usually worth it.

teke184

exactly....good tires are well worth it. i've learned that.

another small upgrade that will help eliminate wheelhop and increase traction is a poly torque arm mount. it's only about $15 and isn't hard to swap in.

i think it's a good simple mod.

Injuneer

Does it only "hop" while doing donuts? When the car is moving in a circle, under substantial rear wheel torque, the posi locks the rear axles together. That means, since the car is turning, one of the wheels has to slip. When you put a vehicle around a radius, the inner and outer wheels have to move at different speeds. The posi screws that up when there is substantial torque to the rear wheels. Now one tire starts to slip, the posi unloads and frees the axles, and the rear will start to chatter and do all sorts of weird things that could be injterpreted as wheel hop. It may also be made worse by the amount of body roll you are encountering, as the body end of the outside LCA is going to be dipping lower than the axle end.... another thing that promotes wheel hop.

Does it also "hop" under straight line accel?

JakeRobb

Uh, Fred, I don't know about you, but when I'm doing donuts, both rear wheels are slipping the whole time.

Greed4Speed

Donuts are a great way to ruin a posi.

Injuneer

Somehow, in my many decades of driving, I have never done a "donut".....