Corvette C5 on a track day

[need 4 speed]

I took my C5 on a track day at Silverstone recently - for the first time. I had a very strange problem and am interested to know whether this is a known issue.

I have the optional Magnesium rims - and after the first 5 or 6 laps I came into the pits and checked the car over to find loose wheel nuts. They were all checked with a torque-wrench before I went out. It appears that heat from the brakes is causing this and I expect it's to do with expansion of the different metals involved.

Has anybody ever experienced this with this type of rims on a C5?

PS - I'm sure I've posted on here before but it says posts = 1... So hi every body!

Edited by need 4 speed on Thursday 12th July 19:24

Edited by need 4 speed on Thursday 12th July 19:27

[te51cle]

I've got the forged alloys and never had a problem like that, never heard of it from anyone else either, odd.

[need 4 speed]

The Magnesiun rims have 5 inserts (I assume it's a steel alloy of some sort) that the wheel nuts tighten onto and a rear flange of the same metal that bears against the hub, presumably because the Mag is to soft. When I got the car home and took the wheel nuts off, one of them was stuck to the insert and it came out with the nut. Strangely this problem was only on 3 of the 4 rims. The back left was totally unaffected. Tyre pressures rose from 30 to 44 psi on this rim and similarly on the other three rims.

If anybody ever has this problem, I'd be interested to discuss this further.

[vetteheadracer]

6 posts 1 month.........

Not heard of this problem I assume you check that someone hasn't greased your wheel studs?

[need 4 speed]

I'm pretty sure this is a heat-related issue. Different expansion co-efficients in the studs, nuts, rims, inserts. I'll get some std rims if I'm doing any more track days... maybe a set of slicks!

[te51cle]

need 4 speed said:

Tyre pressures rose from 30 to 44 psi

That's an excessive pressure rise so something must have generated a lot of heat to cause it. Most I've ever seen is 9psi and that was on a really hot sunny day at Donington Park. Perhaps your suspension geometry is a bit off or there's a lot of moisture trapped inside the tyres ?

[need 4 speed]

te51cle said:

something must have generated a lot of heat

Probably brakes and oversteer

Edited by need 4 speed on Friday 13th July 18:58

Edited by need 4 speed on Friday 13th July 18:59