02impactblue

I have heard about street tires "chunking" at track events but never experienced it until now. I had the car on the lift yesterday for many different issues but noticed my rear tires on the last tread block to the inside on both tires had chunks of rubber missing on the leading edge of the tread. Is this normal and is it safe to keep driving on the track. I have a 2 day event at watkins glen mon-tues. Any info would be appreciated.

Wicked Weasel

I would like to hear what people say. I have always been overly cautious with brakes and tires knowing that they are pretty much the reason for not hitting a wall. people although run many of their tires until they cord so I wonder if some chunks are missing would it make a big diference.


BTW - I got a large group of Vettes together (about 12) for WGI on Monday and Tuesday. You can find the link in the NE section: http://forums.corvetteforum.com/show....php?t=1398685

We have expereinced drivers and non experienced drivers in the group. Come over and hang out with us. It is sure to be a fun time.

Bob

AU N EGL

Graining and chunking may be a result of: overly agressive driving on a tire that was not desiged for such driving; tire is getting too old( too many heat cycles);
More likely the tire was use too hard before the tire was up to opporating temperature.

Source: The Racing & High-Performanc Tire by Paul Haney

John Shiels

Full depth treads get hot because there is more rubber flexing and that's why they shave tires. That's why shaved DOT tires last longer than a street tire run hard. If it's chunking I'd say it's junk.

AU N EGL

Tire is toast.

yellow01

I agree it's normal, I disagree it's junk

I've had Kumho MXs chunk on the inner tread block (the loop that goes all the way around the tire). They had 200 miles on them before a fully dry track weekend and it started. I think it was just pushing too hard with a full tread and overheating.

That said, I streeted (is that a word ? ) them for a few hundred miles and wore down the center a bit.

Since, I tracked them twice more and they held up fine, and actually wore down the chunked areas so now you cannot tell.

It is ultimately your call, and your judgement on how much tread has come out, but mine were clearly jsut the corners of the tread block in the middle and not into the carcass so I thought it was ok, and it has been.

robvuk

I agree with Tom and John. If chunks of rubber are missing, they might be too old. I've experienced what I call chunking by having globs of hot rubber flying all over the bottom of the car and wheels. But that comes from a more even removal of material from the hot tires, not missing tread blocks. I'd be somewhat concerned about that. What kind of tires are they and how old?

mlongo99

I say it depends on how bad and where the chunking is. Mine lost the edges at the side of the tread blocks. It looks like the block was chamfered instead of cut vertically. Seems like that just makes the tread channel slightly larger.

yellow01

Typical for full tread tires that have been overheated... That's how mine went.

More miles & wear fixed the problem

MitchAlsup

Well then consider: That tire is no longer in balance and cannot be balanced because some of the tread blocks that have not chunked are ready to chunk. In any event, if you achieve any high speeds, this tire will become dangerous.

A chunked tire is a sign that the driver is driving too agressively. A driver in tune with his car will be able to feel the temperature in the tire; as the tire becomes greasy considerably before it starts to chunk.

yellow01

Disagree, I've done it. The tires were fine. Maybe we're talking different levels of chunking though. Hard to say without photos.

For me, the inner treadblock that runs around the entire center looked like a mouse chewed on teh corner of the block all the way around.

I guess I wasn't in tune.

02impactblue

The tires are the stock z51 supercars on the 2006 c6. They have 4800 miles and have been through 4 autocrosses and 5 track days. They didn't show any signs of chunking until after my last autocross this weekend.

02impactblue

What is goodyear going to say when I try to make a warranty claim?

C6400hp

Do they look like this?






If they do I say please do not use them on track. Might be OK to run around the street on but, no way I would chance it at the track. What you are talking about sounds exactly the same as what I experienced with my stock Goodyear F1 supercars pictured above. That is from 2 autocrosses. Let us know what Goodyear says.

02impactblue

Thats exactly what mine look like. They where fine until last weekends autocross. They didn't have the problem on the high speed road courses just 50 mph autocrosses.

yellow01

ALright, we may be speaking two different languages - my bad.

My MX's NEVER did that. What I saw was the top corner of the interior treadblocks chewed up - looked like someone took a really rough file to the corner of the treadblock all the way around the tire.

NOTHING like the above...

So sorry if I caused any confusion!

02impactblue

I noticed the tire issues when I had it on the lift servicing the rear for noises I was hearing following a weekend autox. The rear was grinding/popping/chattering during slow tight turns. I was wondering if the rear was not allowing the inside wheel to slip enough during tight turns and grinding away at the inside tires. I have autox for years and never had a tire do this.

mlongo99

That tire is definately done.