There's been a few mentions of the wheel bearing issues, but i couldn't find a thread that focused on it singularly - so here goes.

The GM wheel bearing design and even the SKF upgrade are inadequate for racing ! (that should get some people fired up).

I'm not aware of the rules in SCCA but i think you guys are required to run the standard parts, but for FIA GT4 and GT3 we can't change the hub/wheel bearing as it's homologated (yep GTE guys can) so we're stuck with the SKF as the best solution.

Wear.
It's amazing how they fail, you can't feel any movement by hand in the wheel - but you know there buggered when either
i) the brake pedal starts feeling a bit funny
ii) the pads start showing a very funny wear pattern - top to bottom
iii) inner lip of your rims start touching the rear part of the lower wishbone (rear).

The problem is obvious - the ball races are just too close together - yep SKF have tried to get some triangulation on the load with making one of the races bigger in diameter and it certainly helps.

But what stumps me is how there doesn't appear to be a better solution. (that's a queue for someone to say there is)

This must affect lots of C6 racers - surely ?

 

Don't see wheel bearings discussed much here. You will probably get more action over in the Roadracing Forum. Just sayin'.

http://forums.corvetteforum.com/auto...roadracing-23/

 

i'll shall move it over there - many thanks

 

We had the front wheel bearings replaced under warranty at about 25k miles and 4 HPDE on our C5. Dealer said the heat from hard braking can melt the grease out of the bearing and then it begins to fail. Unable to verify if this is correct.

 

The SKF race bearings were designed for GT3 based on what my contacts at SKF told me. T1 guys use them and they don't report any issues with the SKF bearings that I am aware of.

I have them but only do a few track days a year, plus I am old and slow, so I am not stressing them like a real driver would.

 

I should point out that I'm talking dual master cylinder setup on a balance bar and no servo and no ABS. (the 'no servo' may be a key item, along with the ubiquitous use of Bosch Race ABS now, and how it has changed the way people brake for corners is another thread altogether).

The 3 other GT3 runners i know, all seem to work on the basis of a regular (twice a year) change being the best strategy. Those running the 12hr/24hr events seem to install new for the event. A Japanese team have apparently re-engineered the uprights to take a different bearing hub altogether (their working on the idea that no one will notice). Another team had considered using the std item and binning them after each event.

The symptoms that onset when they start to 'fail' are not progressive like people may be used to. You can't perceive any moment in the wheel/hub but the break pedal will quickly become as spongy as hell due to the pad knock off/wear.
The onset is like a step change - which is the issue as once it occurs you can't continue racing with a brakes behaving like that. (had this happen, they started to get a little spongy and then at the end of the main straight at 165mph the fronts just vanished resulting in huge spin and soiled underwear).

The original owner of my car - had fitted master cylinders (forget if they were very big or small) that basically gave max braking and no feel/control to overcome the pad knockoff and taper wear - but that made 'feeling' the braking impossible.

Given the wheel/tyre sizes ( 12"/300 & 13"/330) being run and compared to what you get on say a Porsche they really look a little wimpy for the task and given that everything else on a Z06 is seriously tough - this just seems to be the 'Achilles heal' so to speak.

 

Are the hubs an issue in 1/4 racing or just autocross?

 

This thread is best continued at....

http://forums.corvetteforum.com/auto...post1582699208