GrantB

I'm looking to get some coilovers, and read conflicting reports on how much bump travel you can get out of C5s. Without drop spindles or modified upper shock mounts, is it possible to bottom the tire out on the fender or bottom the fender out on the ground? If so, which shocks would have a short enough shock body to allow this?

I'd measure myself but my control arms are off waiting on some Moog ball joints.

When running a C5 as low as it can go, does bump steer become more of a problem? I've played with front bump steer on another car. Aside from making it more pleasant to drive reducing, bump steer from about 0.1" per 1" of travel to zero did not measurably affect lap times.

According to Suspension Analyzer, front bump steer decreases with lowering while rear bump steer increases slightly. However, some inconsistencies in the software make me question these results.

Do most people zero out bump steer using the LG kit, or similar? I'm tempted to as I think I'll put aero on the car eventually, but am not sure if the roll steer GM designed into the car was considered beneficial or not.

Thanks for any help.

Nowanker

I went through my C5 a couple of years back... forgot the details on the front, but for sure in the rear the tires will hit the body if allowed enough travel. I suspect the front was the same. Lowering the car reduces allowable suspension travel, and lowering spindles won't help that. I adjusted bump steer using the Baer racing kit (F&R), but hadn't tracked the car prior, so I can't tell you what effect it had. I was concerned about removing the 'roll-understeer' from the back of the car, but on track manners were great. stock F41 springs/bars, Bilsteins, 275/295 NT05s

GrantB

Thank you for the response. Do you know if those Bilsteins were factory length?

Apocolipse

The only smaller ones available are coil over shocks, pay to play.

Nowanker

Yes, the Bilsteins were just off the shelf. I had some custom upper rear shock mounts made, to raise the upper mounting point up into the hole in the chassis. It got me maybe another inch of travel... over the biggest bumps, the tires just skim the inner fenders.

GrantB

Alright, I've done similarly with other car.

Yes I was planning on going with coilovers, but there are a lot of options and I've no idea which would allow full shock travel. If none would then I'll need to modify the shock mounts anyway and shock length differences between products may not matter.

jtmck

Give Ridetech a call.

GrantB

Do they offer racing suspensions? Their site seemed to be more street-oriented.

I was hoping this sort of thing would be common knowledge. I always set up my cars to take advantage of every possible mm of bump travel.

Apocolipse

You can always cut the bump stops but eventually you will get to a point that the tire will hit the fender inside.

jtmck

They do race suspensions.
I have Ridetech coilovers on my car.
Give them a call.

Bret is the owner, Britt is the engineer. Probably anyone should get answers for you.

Jim M.

Matt_27

Interesting... do you have any pictures of those mounts?

Nowanker

I'll snap some next time the car is in the air.
(from memory...)The stock ones center the mounting rubbers below the frame. I took dimensions off the old ones, and had my CNC neighbor make some that put the mounting rubbers up inside the hole in the frame, with the top of the shock ~ 1/4" below the frame plane. I needed to space the stock bumpstops down a little to stop the tire touching the inner fender at full bump.
I'll see if he still has the dimensions...

Matt_27

Awesome, thanks. Sounds like a useful thing to do to prevent getting into the bump stops when running a lower ride height.