Carboy

I have just put some Kinesis custom wheels on my 951 but the tires keep rubbing the rear fender. I can't roll the lips because I have just painted the car and don't want to do more body work which would be required according to my body shop. I've also noticed that this car squats more than nornal. My car is chewing up sidewall of tires from the rubbing and I can't accelerate hard without the rubbing. The bad thing is that there is at least 2 inches of gap when the car is just sitting there. Should the car squat that much under acceleration?

Will lower stiffer springs stop the extra squating? I don't want to raise the rear because I like the low look. What can I do to beef up the rear end and stop the rubbing?

Dan87951

Rear coil overs? But they are expensive.

Danno

You've got two options:[list=1][*]send the wheels back to Kinesis and have them increase the offset. If you look on the inside of the rear wheel (drive up on ramps, do not jack), you should see plenty of clearance between the tire and the parking-brake cable near the spring plate? Take this clearance and divide by 2, then add the result to the current wheel's offset. This is the new offset you should have Kinesis re-build your wheels to. It will precisely center your wheel between the fenders and the spring-plate. In fact, I'm able to run 17x11.5" rear wheels with 275/40-17 tires with zero rubbing.
[*]roll the inner lip of the fenders.This will not affect our bodywork if you're careful. I don't like the baseball bat method because it distorts the fender. I prefer to make 1/4" cuts 4" apart in the fender lip first with a hacksaw. This allows the metal lip to bend upwards without having to stretch. Then I place a 1/2" thick metal plate over the outside of the fender and line up with the edge of the fender. Use a pair of channel lock pliers to squeeze and bend up one 4" section of the fender lip at a time. The metal plate ensures that no movement of the bodywork takes place. All the force is going into bending up the lip.[/list=a]

H Dog

The Tire Rack has fender rollers which they apparently lend out for a small fee (+ deposit). But I like the idea of sending the wheels back to Kinesis.

Carboy

Thanks for your responses. Do any of you know if regular eibach springs would eliminate all the sqatting?

keith

another idea - get rid of the SOFT factory T-bars - go 25.5mm or larger (and of course, increase the front spring rate to match)

Luke

Carboy,

Checkout www.morissdampers.com
They have made a great setup for the 944s2/turbo varients.
I personally have been for rides in my buddies s2 with the morissdampers gas-emulsion coil over setups. They are AMAZING!!


ON a totally OT note.....why is it that addressing somebody as "car boy" makes me feel like Eva Save-alot on a 1 800 collect commercial?

Jason @ Paragon Products

You may just want to try something like a set of Koni Sport Yellows. They'll be stiffer on the compression stroke than what you have (perhaps stock?)and may eliminate enough squat to solve the problem. Certainly it's not a sure thing, but it's easy to do; solves a maintenance issue; improves the handling/ride of the car; is much easier than changing torsion bars; less expensive than coil overs etc.

Danno

Limiting suspension travel to avoid rubbing a tire is NOT the solution to the problem. It's a sweep-under-the-rug-and-pretend-its-not-there kind of a fix. After all, the squat from acceleration is minimal suspension travel compared to cornering. And what about hitting bumps and potholes? You should really set up your suspension so there's no interference throughout the entire full suspension movement; including bottoming both the front and rear.

Then you can adjust spring-rates and shock-valving to deal with the types of bumps you're going to encounter. For a street car, to set up with just 2" suspention travel so that you don't rub is simply crazy.

Jason @ Paragon Products

Danno, I'm not sure who's post you're responding to but I don't see any recommnending limiting the amount of suspension travel. Even with stiffer torsion bars or shocks the suspension travel will still be the same...just more resistant to travel. Ideally, the wheel/tire issue should be resolved, but there may be issues that are allowing the car to squat more easily than is normal.

TurboGuy

Carboy,

The only real answer here is to fix the problem. Replace the front and rear suspension with coil overs that have adjustable ride height. Select a spring rate that wont squat. I have 600# fronts and 400# rears with torsion bars still in use. You will have a nice firm ride that will allow you to safley lower you car to the ride height that suits your needs and be able to corner balance your car at the same time for improved balance and handling. Keep your wheels fix the problem !

Carboy

Thanks for the feedback. Since I want to improve the handling anyway, I may do the shocks, and torsion bars. The question is the priority. Do I really want springs? Or just shocks with the stock soft springs, or vice versa? Should Perhaps I should just do the torsion bars. Does anyone have and insight as to what each one of these will do for the car if individually done?

Andrew

I agree with Danno here. You need to fix the wheel offset not the suspension. If you are 'squating' alot then address that problem separately. the rubbing is just wrong sizes or offsets. What tire sizes are you running and what is the offset and wheel size of the wheels?

-Andrew

Danno

Sorry for the confusion Jason, I should have used "reduce" rather than "limit". And I was really referring back to the orignal post: I'm inferring from his statement that Carboy wants to reduce his suspension travel to less than 2" under acceleration so that the tire doesn't rub the fender. Which immediately leads me to think that something is seriously wrong with his wheels' and tires' sizing already. A stock car will only have 0.25-0.50" of vertical clearance anyway. If you lay a straight-edge/ruler/yardstick flat across the top of the rear tire, it will stick out and have only 0.25-0.50" of vertical movement before it hits the fender.

A quick synopsis of cause & effect relationships:



Usually the cause is a situation or a problem or an event that occurs which creates an effect, also known as a result or a symptom. We all know about illnesses and their symptoms and how treating symptoms don't really get rid of illness (it may make you feel better, but you're still sick). So by eliminating the effect/result/symptom:



what have we really done? Not much because the cause of the problem is still there. You may be able to mask it by treating the effects or symptoms though. For example:

Why doesn't this fix work? Because the doctor's been fixing the effects or symptoms of the problem, not the problem itself! If he investigated further, he would have simply fixed the problem by saying, "have your gardener trim the rose-bush that's growing low over your front door"! So by removing the cause of the problem, the negative effects and results never happens:




In Carboy's case, results/symptoms we're having here is that a tire is rubbing on the fender. By reducing suspension travel during acceleration with stiffer shocks/springs we're applying band-aids and will have the following progression:[list=1][*] stiffer shocks/springs for acceleration -> rear end squats 2" now instead of 3" (no rubbing, great)[*]car leans under cornering and rubs (arrgggh, shock/springs not stiff enough)[*]even stiffer shocks/springs for cornering -> rear end squats 1.0" now, no rubbing under cornering[*]car hits big bump/pothole and rubs (Grrrh.., shocks/springs still not stiff enough)[*]ever stiffer shocks/springs for bumps (no more than 2" travel) -> rear end squats 0.25" now, no rubbing under bumps/potholes[*]speed bumps? bigger potholes? etc.[/list=a]Great so now you've got a super-stiff car that rides like a Ryder truck. It can't corner because it's bouncing off all the bumps. But hey, it doesn't rub the rear tire, right?

By treating only the effects & symptons which is: tire rubs on fender with more than 2" suspension travel you are still leaving the cause of the problem unchanged. That cause is: incorrect wheel offset. The test for whether you've fixed this problem is, "Does the tires rub anywhere along the entire travel of the suspension?".

Because at some point during the use of your car, you WILL use all of its suspension travel. In fact, we have a suspension for a reason and you want the car to use it. If you hit a 3" bump, you want the wheels to move all 3" to keep the body steady. But if suspension only moves 2", the car's body will be pushed up the last 1" and the result is less control and grip.

By only treating the effects with band-aids like stiffer shocks/springs, it's a temporary fix because the real problem is still hanging out there, waiting to bite you when the opportunity comes along (or a bigger bump/pothole, heavier sorority chic, etc).

So like Andrew said, the shocks & springs are a completely separate issue from the tire rubbing the fender. You can fix that symptom without ever touching the shocks & springs, and it'll give you a more permanent solution as well.



P.S. the problem is not: "The rear wheel moves too much", just in case you guys are wondering.

Danno

These are these are the optimum wheel offsets you should use for zero tire rub on an '87 951:

FRONT

• 7":52.3mm (stock)
• 8":60mm
• 9"-10":65mm (2.5" coilover kit required)
• 10.5":65mm (fender rolling required)

REAR

• 8":52.3mm (stock)
• 9":60mm
• 10-11":65mm
• 11.5":65mm (fender rolling required)

Yes, that's right. With the correct offsets chosen, you can run 10.5/11.5" wide wheels on a 951 without rubbing. That's no rubbing through the entire travel of the suspension. Again, shocks and springs have no relevance in these clearance issues.