Z Fast

I was preping my C6Z06 for an upcoming HPDE and I noticed on the OEM tire what looks like cords barely showing through on the thread blocks. The tires are at or slightly below the wear bars. I shave tires (different tire brand) for my race car all the time to where there are no threads left, and there are no cords showing.

I find it odd that there would be cords in the thread blocks. Anyone have experience with running these tires on track at this level of wear. I think I will have to cancel on driving that day and just instruct.

Any thoughts appreciated.

Tom

davidfarmer

I've chorded several sets of the OEM tires, and haven't seen what you refer to. We've been running our down to slick before hitting chord.

Maybe take a razer blad or utility knife and slice a bit deeper. Maybe something just slipped into the mold in your case, and it's just floating up in the tread at that particular spot.

Z Fast

David,

Running down to slick is exactly what I would expect before hitting any cord. I saw this on one front and one rear tire and several spots on each. I have a local GY shop in town. I will take it to them to get their opinion. Regardless, I will order a new set, I'm just courious to why they show cords in the thread block.

Tom

John Shiels

don't see how a line like a cord could go from block to block in the mold. It would have to bend in and out.

Z Fast

John, I totally agree. The cording isn't consistant. Just a few spots here and there. Thats why I want to have a Good Year shop take a look at it to get there opinion.

I have to wonder since I'm slightly below the wear bars (about 1/32") if hot pressures caused the thread blocks to take more wear, but the again, tires are not completely slick.

I never saw this before on any other tire, and I have corded my share.

BEZ06

Are you talking about something that looks like this?




The cord is showing only in this area - the rest of the circumference of the tire is okay. I've been running 30-31 psi cold on the street, a couple psi higher on the track.

This tire is an OE GY, and is currently on the left front of my C6 Z06. I had it on the right front for 8 sessions of an HPDE in December (at Daytona, and the right side tires take a beating there), then swapped it to the left front for the last 4 sessions of the event on Sunday. I noticed just the slightest cord after the 3rd session on Sunday but it looked good for one more session, and it didn't look any different after that last track session - just a barely visible couple of cords showing in about an inch section in that area.

I thought the tires would be shot after the event, but I've been running them on the street since then and have gotten another 1500 miles or so out of them - I took this picture just a few minutes ago. I've got another set of OE tires I'll be putting on in about 2 weeks before driving up to VIR for the NCM event the end of this month.

Bob

Z Fast

Bob,

My wear is different. As where your cording crosses over the groove, mine is limited to just a few thread blocks in the same line(without crossing the grooves). It looks like I penetrated the second layer rubber on those blocks as the primary layer can be peeled back.

BTW, your wear pattern looks like it is possible the hot pressure was too high. Hard to tell from the picture, but it looks like you have more wear in the middle of the tire. I noticed you said you are running 30-31 cold on the street and a couple of psi higher on the track. If that higher pressure on the track is measured cold, I can almost be certain the hot pressures are way to high. I have started cold with 30-31 psi before and have the DIC warning of high pressure and a reading of 42psi hot. Since, I start at 28 cold for the track and adjust when hot as needed. Depending on track and conditions, I shoot for 38 psi hot. I usually get good traction and tire wear.

Thanks for the pic and your feedback.

Tom

BEZ06

Tom

I think you're right. The right side tires take a beating at Daytona and when I had that tire on that right side, the pressure got up to 42 psi. There also are some small bits of rubber missing in that area, and I imagine you are exactly correct about the high temperture and pressure affecting the tire.

Thanks for the insight - I will start with a little lower cold pressure and adjust from there.

Bob