NewFoundPower

My current track tires are Falken RT-615s on stock Z06 wheels, 255/55 up front and 315/30 in the rear. My tread is wearing very quickly and I wanted to see if there is a minimum depth I need to keep before they are "worn out" for use on a dry track.

I would think that tread depth doesn't matter if the track is dry, as long as cords aren't showing. There would just be more contact area as the tread wears - but are there any other considerations that I'm not thinking of? The tires are about 6 months old, kept in my garage in tire jackets when not in use. I don't want to replace them if I don't have to but I do want to be safe of course. They have 3 events and maybe 2000 street miles on them.

AU N EGL

as long as they are not corded.

Many times the best street tires are at the wear bars.

spazegun2213

I'ved tracked on some tires I'd NEVER use on the street

sperkins

It's not the tread depth that's important, it's the age of the tire. Rubber hardens with age so if the tire is old and worn it will be worse than a tire that is worn out yet newer.

varkwso

If the tire is fresh and not too heat cycled a worn tire is fine at the track. I threw away a 4 year old set with hardly any wear this month off the Mustang race car...track pads (from a tracked vehicle) had more grip

V8 Juice

Whoever posted this message is an imposter...the real Varkswo would never throw a tire away...he'll just get it hot enough to melt and then it will have grip, a trick he learned from watching funny cars run 1/4 mile!!

dbirdz06

I thought it was 3/32".

NewFoundPower

There are exceptions!! haha. I was just asking to see if wear would hinder grip at the track. They're still doing well but wearing fast so I wanted to be sure.

Solofast

Some street tires have an "undertread" that is used in the carcass that doesn't have much grip. The tread face has the rubber in it that has grip, the undertread is slippery. The undertread is stiffer and stronger to make the carcass work right, but it doesn't stick worth a darn.

If you can see a color change to a slightly blacker tread coming thru then the tire is not going to work well. I am seening it on the stock OE Goodyear F1's so they are done, but they are also pretty near cording FWIW....

NewFoundPower

That sounds like what I probably should have asked in the first place. So as the tire wears the rubber grip changes (on some tires)?

sothpaw2

Is 4 years the limit for a street tire on track? I have some front's I'd like to use for 1 last event that will just turn 4. They are only used for track days & garage kept.

I hate to throw way tires.

Solofast

Right, if you can see the carcass rubber the grip will fall of pretty quickly. On some tires the way the tread is molded pushes the undertread up into the tread for a distance. The designer is trying to get more stiffness in the tread blocks and that makes the tire more respnsive and less likely to chunk because the undertread is stiffer and makes less heat, so the original tread can be deeper and not chunk.

On those tires you will see the color change in the surface of the tire and it will look like a shadow of the original tread, even though the original tread is gone or nearly gone.

I have seen this on some Bridgestones, but it was a good while ago and I forget which ones they were.

Other tires don't have as much of an undertread compound difference and you can run those tires down to the cord and they will work until you blow them out.

varkwso

It really depends - a durometer is the best way to tell. A 4-5 year old tire really serves best as a swing in the back yard or a planter in the front yard at Falcon's mobile home park. They will take a while to come to grip and will fade fast once they do.

After tapping the armco at Barber due to trying to get the last bit of tire life, and not driving the tire I had on the car, I realized I did not have the maturity needed to run crappy tires anymore

V8Juice - I still run most of them to cord....

sothpaw2

Is there a durometer tester? At least w/ fronts I would induce more understeer. Usually w/ a Z06 it's oversteer due to poor throttle management that gets you in trouble. I wouldn't even consider running anything over 3 yr on the back.

USA1C5

I thought most inspections for the track require 3/32" but I do think the less tread the better on a dry track as long as there is no cording, of course more tread the better on a wet track. Maybe the 3/32" requirement is just in case of a wet track.

NewFoundPower

I was on a wet track with these tires when they still had right at 3/32" left, and it was enough to keep me from doing that again. I thought cold was bad but wet is a whole different ballgame. Not for me!

AU N EGL

I am cutting up old tires with a sawsall to make a back stops for target practice

AU N EGL

Yes and no. Keeps the club safe and to make sure your tires are not corded.

zcobra1

Great timing on this thread...As I have the same question on my specific tires, Nitto Extreme RII- they are down to the wear bars-but only a year old manufacture... are they safe for running say the ROVAL here in Fontana ?
Or any track for that matter--I was going to save this set for local- so no far driving to and from the track-

Bill Dearborn

The usual rule is 2/32 which is the legal minimum tread depth in a lot of states. It is also easy to check since the wear bars are set to show a tell tale at 2/32. That way you don't need a tread depth gauge. All the inspector has to do is look at the tire.

Bill