Z06Vette.com - Corvette Z06 Forum

DJWorm · 07-31-2006, 08:18 AM

WARNING: Especially for those that track their cars.

Upon hard suspension compression while cornering, the C6 Z06 front hood support mount bolts will contact the inside of the tire sidewall as the bolts are too long.

These 2 bolts are located holding a silver bracket to the inner fender well/front frame support.

This has been reported on cars that have been tracked, especially on high speed ovals.

You should:
1. Inspect the inner side wall of each front tire. If effected the tire will have a descernable grove in the side wall just inboard of the tread/side wall shoulder border. You MUST replace the tire if effected.

2. Replace the bolts with shorter shaft bolts.

3. Others have also noted front tire contact with the front brake cooling duct under similar conditions and in a similar position on the tire. A Brake Duct Extensions will worsen the problem. Check the brake duct edge for fraying and the tire for a "rub" strip on the inside tire wall.

4. Another thing to examine is the inside shoulder of the rear wheel for contact with the rear transverse spring mounting bracket. This can sometimes contact the wheel under hard cornering and suspension compression at low & high speed, especially if wider rear wheels are used...but will not be apparant under static conditions. Look for metal shavings and a scar on the rear wheel's inner shoulder. (This condition has only been reported on C5 & C5 Z06's with wider than OEM rear wheels but warrants consideration here.)

If effected, Chevy should replace any effected tire and bolts with shorter bolts under Warranty. I wouldn't voluntarily reveal that the car is trackled, however.

5. You may be able to file away enough for clearance on the brake duct or reposition slightly to gain appropriate clearance.

6. A 1/4" wheel spacer or more + wheel offset may be necessary to widen the track and gain clearance.
I recommend having race wheels built with the SCCA allowable +0.25" offset for the track.

lateapex · 07-31-2006, 11:19 AM

Quote:

Originally Posted by DJWorm

6. A 1/4" wheel spacer or more + wheel offset may be necessary to widen the track and gain clearance.

Actually, that should read, “less + offset”. Corvette factory wheels have positive offset. The less positive offset, the wider the track, or the more the rim is moved away from the suspension components and toward the outside of the wheel well.
http://www.tirerack.com/wheels/tech/...jsp?techid=101
http://www.discounttire.com/dtcs/infoWheelOffsets.dos

Thanks for the heads up on all of this.

ZO6 AL-X · 07-31-2006, 11:51 AM

Uh oh.

wakeupii · 07-31-2006, 12:21 PM

Has this been corrected for the 97 Zo6's?

**RC45** · 07-31-2006, 12:30 PM

Quote:

Originally Posted by wakeupii

Has this been corrected for the 97 Zo6's?

Don't hold your breath, I am still patiently wating for a fix for my 2001 clutch pedal..

But on a serious note this shows why its a good thing to get your car up on a lift as often as possible to give it a once over when ever you can.

**wvphoto** · 07-31-2006, 02:29 PM

thanks worm.. you are always a great sourse of info

ZL-1 · 07-31-2006, 09:54 PM

I wonder if this only occurs after re-alignment with a lot of negative camber ?

bjaber · 08-02-2006, 12:00 AM

Thanks for the info...I'll check mine. I haven't tracked it, but I have cornered hard a few times.

Top Cog · 08-05-2006, 11:57 AM

Following DJWorm's advice, I cut the two bolts on each side. The offending bolts are the forward ones on the hood latch mechanism. Mine were 1/2" longer than necessary. Easy enough to hacksaw 1/2" off each bolt and chamfer the ends with a file so you can re-thread easily. Remember remove only one at a time from each assembly and you won't have to do any re-adjusting. So far I've pulled only 0.72 g's but this is good insurance.

Thanks, DJWorm for the tip. Now I need to inspect the brake cooling duct.

bjaber · 08-05-2006, 12:09 PM

Just checked my tires and they are OK. Here's a picture of the bolts (in case anyone is wondering).

This is the Driver side, BTW.

BTW, You'd have to be seriously cornering hard for those bolts to rub the tire....that's a LOT of travel in the suspension, but I do see it very possible to hit them.

Thanks for the heads up on this.

JCEng · 08-05-2006, 12:47 PM

VERY poor design by GM. In the industry, EVERY effort is normally be made to keep items like this out of the three dimensional zone that the tire can possibly occupy (the FLOP) - including tire distortion, alignment, bushing deflection, etc. etc....

This could have been a late change requested by the plant to either commonize a fastener (with another one that is longer) - or somehow to get the assembly task done. This should be fixed now by GM!

Andi · 08-07-2006, 12:00 PM

Quote:

Originally Posted by DJWorm

WARNING...

4. Another thing to examine is the inside shoulder of the rear wheel for contact with the rear transverse spring mounting bracket. This can sometimes contact the wheel under hard cornering and suspension compression at low & high speed, especially if wider rear wheels are used...but will not be apparant under static conditions. Look for metal shavings and a scar on the rear wheel's inner shoulder. (This condition has only been reported on C5 & C5 Z06's with wider than OEM rear wheels but warrants consideration here.)

On my first set of rear tires, the right rear tire exhibited major chafing on the inner sidewall. I actually called my dyno shop and asked if there's any way the strap contacted the tire; they said no way. Now, seeing this post, I wonder if perhaps I have this problem? Anybody got a pic of what I should look for in terms of the offending bracket/etc that might be hitting the tire?

This is quite disconcerting as this car has never even touched the pavement of a road course... all it's gotten is spirited driving around twisty roads here and there. I love going to Motorsport Ranch / TWS / etc but never made it out there with this car because of all the stories I heard about the brake pads being toast in one day.

Andi

bjaber · 08-07-2006, 02:35 PM

The issue in this thread only affects the front tires, not the rear, to the chafing could not have been affected by this issue (unless there are OTHER bolts in the rear wheel wells that are rubbing the rear tires!).

You haven't taken the car to any car washes have you?

Andi · 08-07-2006, 03:05 PM

Quote:

Originally Posted by bjaber

The issue in this thread only affects the front tires, not the rear, to the chafing could not have been affected by this issue (unless there are OTHER bolts in the rear wheel wells that are rubbing the rear tires!).

You haven't taken the car to any car washes have you?

No automatic carwashes.

According to DJWorm: 4. Another thing to examine is the inside shoulder of the rear wheel for contact with the rear transverse spring mounting bracket.

That's why I asked......

Andi

allanlaw · 08-07-2006, 06:22 PM

I'm not sure from reading this whether it's a problem when wider front tires are used (since these are cars that have been tracked HARD) or also with stock tires / alignment. I would imagine that GM would have tested clearances with stock tires being used - let the modder beware (or be careful), as always. I haven't seen any issues with 18x285 in the front, -1.7 camber. On the other hand, I don't run on high-speed banked ovals . . .