Oskar_Z28

Over X-mas I put Eibach springs in my car. I also got Enkei V1 (9.5" wide) rims with 275 tires. The car sits pretty low and sometimes when I go over large bumps I get some grinding from the back. I was thinking that by replacing shocks with Koni adjustables or Bilsteins I could eliminate that.

However,

Supposedy I wanted to make a high speed run in my car and at around 145 mph the car starts to make loud - what sounded like tire grinding noise from the back. Could it be that the rear end (due to aerodynamic forces) squalts low enough to make my tires rub? I will experiment by putting stock springs in the back of the car.

Any comments or observations?

NoGo

iTrader: (2)

I doubt your clearance between the wheel and hub is that close. Otherwise daily driving would be a menace.

I doubt that the arodynamics of this car apply much positive downforce, if any. If you do believe that it is tire/well rubbing, then it could be tire expansion. Your tires at speeds over 100 will actually inflate to +6 psi (I think it is 6, somebody correct me if I'm wrong) greater than you normal standstill pressure. If your rims are wide enough, you could be rubbing against the wheel hub lip at these speeds with a slightly bigger tire.

I doubt this is a good thing. A blow out at 120+ I don't think would be much fun.

Oskar_Z28

You know what? I was thinking about the tire expansion thing too. The tires will grow taller at higher speeds (by how much I don't know), but it might be enough to touch the fender in the back. With my car lowered plus all the extra stereo weight I have in the trunk, this could cause a problem.

NoGo

iTrader: (2)

Also, another thing that it might be:

Understand that at that high of speeds, it is very easy to compress your suspension more than normal driving. Even slight differences in road incline can cause your front/back end to float or compress.

I can say from personal experience on certain stretches of freeway that I can normally travel at 80-90 no problems I have had some close calls with the front end floating, or bottoming out when at speeds in excess of 120.

If you are experiencing constant noise this may not be your problem.

When at those high speeds, tire rubbing sounds more like a circular saw through wood than tire rubbing. It is very very high pitch. My front tires have a tendency to rub when bottomed out.

Chris Spiess

I've got sportlines on my 98 and haven't had any issues up to 150. Stiff sidewall street radials or road race tires won't grow enough to cause a problem. Which eibachs do you have? My rear axle was pretty far off center with the sportlines and I could see that causing the right rear to rub the inner fender well.

SILVER BULLET

iTrader: (1)

When I lowered my car I had to get an adjustable panhard rod because when you lower these cars, the body shifts left or right. Look and see if the tires stick out more on one side then the other. After I replaced it, at high speeds and curves and over bumps I no longer rubbed the tire.
Dave