How do you tell when slicks are done?

I have Nitto NT-01s as track tires for my Miata. They're getting old, and I'm trying to figure out how many events they have in them (they are wearing like iron, and have lasted me a solid 10 events already).

I know there are the little circles to see depth, and there's still some on the outermost ones.

My concern is that I don't have enough camber, and so the shoulders have gotten more wear than the rest of the tire. Is there a good way of judging how much longer the shoulder will last?

dont you normally just use them until they either get too hard (as in no more grip) or the cords start to show?

x2 on Travis' comment. That's the thing about race tires. And "DOT Construction" race tires like the NT-01R (or even the "street" version) are still race tires.

If you use them a lot, they get hard long before they get down to the carcass.

I was racing in SCCA Improved Touring back when this (DOT legal tires with soft compounds) first became an issue. The tires were actually created for the professional "showroom stock" series back them, but because they fit on our rims and conformed to our tire rules, we all scrounged up enough to buy them. Even Hoosier entered the market back then, and I've never seen a real street car on them..

Invest in a pyrometer and start documenting the temps across the tire surface.

And use Travis' advice, too!

Travis_K wrote: dont you normally just use them until they either get too hard (as in no more grip) or the cords start to show?

+1 on "when you see cords". The Nittos aren't like a real slick - they wear similar to an RA-1 in that they will cord long before they get hard from heat cycles unless you are not pushing them.

If you don't have enough camber flip them on the rim after 5 or 6 days to extend their life. Once you wear off most of the 1st layer the direction does not seem to make any difference to lap time.

Most solo tires I've run (Hoosier slicks) will heat cycle out before they cord, not all, but most. You can get a durometer from Summit or other shops that will allow you to check the rubber's hardness.

If you store them in a non freezing climate and keep them covered in dark trash bags away from the light it will help with the tire life.

Gonzo_Bmod wrote: Most solo tires I've run (Hoosier slicks) will heat cycle out before they cord

depends on the surface... my buddy corded a brand new set (actually only one front tire) of A6's at one auto-x, 4 runs with a well set up WRX ... but still it was toast due to the cheese grader surface of that parking lot

I'm cheap, so I run them until they cry. Your mileage may vary.

I don't know the answer, but I have a bit of a follow up question....even as they harden, can tire treatments soften them back up a bit? Something like Formula V?

I've never used one but have heard some positive results. Any feedback?

Yeah, wait until you see little steel wires sticking out of the rubber.

So... just bring a couple spare tires to drive home on from the event where my tires cord. This is a Miata, and I drive to and from events on the same tires.

I figure I can get away with only 2 spares, since I don't wear all 4 equally.

In reply to Tom Heath:

Uh, Tom? I don't mean to be rude about your braking skills or anything..but that sure looks like a "flat-spot".

Pat wrote: I don't know the answer, but I have a bit of a follow up question....even as they harden, can tire treatments soften them back up a bit? Something like Formula V? I've never used one but have heard some positive results. Any feedback?

I've also heard they work, but the skeptic in me notices none of the sanctioning bodies have banned them yet (to me, that would be a sure sign it's an avantage).

OTOH, I've been out of the sport (as a participant) for about 15yrs. I'm sure I missed a lot of rules changes in that time..

friedgreencorrado wrote: In reply to Tom Heath: Uh, Tom? I don't mean to be rude about your braking skills or anything..but that sure looks like a "flat-spot".

Well, yeah...but it's a flat spot on cords. I had a hard time getting used to the lack of ABS in my Miata until I discovered how much bigger, stickier rubber helped.

Tom Heath wrote:

friedgreencorrado wrote: In reply to Tom Heath: Uh, Tom? I don't mean to be rude about your braking skills or anything..but that sure looks like a "flat-spot".

Well, yeah...but it's a flat spot on cords. I had a hard time getting used to the lack of ABS in my Miata until I discovered how much bigger, stickier rubber helped.

ROFL! Sounds like you managed to get the car back on the line with the little ones, though. I guess I'm still thinking like a circuit racer, instead of an autocrosser. Maybe that's why I'm so slow?

Pat wrote: I don't know the answer, but I have a bit of a follow up question....even as they harden, can tire treatments soften them back up a bit? Something like Formula V? I've never used one but have heard some positive results. Any feedback?

I know USGUYS RACING has used in the past tire treatments. We have found that you can bring an old tire back to life. Our testing we found that there not fast ( at Blackhawk) there about .5 sec off the pace of new. We did not used Formula V, but some Kart tire treatments. They have some that are ready to go in a about hour.

Mike Machi Crew Chief USGUYS RACING

Tom Heath wrote: I'm cheap, so I run them until they cry. Your mileage may vary.

I'm ashamed to admit that I've auto-x'd on worse.

so how do you tell if a slick is done... stick a fork in it?

A slick is done when it doesn't hold air anymore or when the surface is less than 40% rubber and is greater than 60% nylon cord. Whichever comes first.

Or second, depending on your budget.

Please help. Locked my brakes on GT3 and made a horrible flat spot on my loaded side tire Hoosier R6. Don't tell me off, I know what I did.. I need obviously more braking modulation. The tire has a good amount of life except on the flat spotted area (have done about 5 sessions on these Hoosiers. My first time on Hoosiers), where the chords are 100% visible (probably a 10% of the whole surface). Can I still use this tire if i move it to the opposite side (not loaded side)? Thank you very much in advance for your insight.

http://www.flickr.com/photos/87442173@N07/8006770650/ sorry...here is a pic of the poor Hoosier!!!

http://www.flickr.com/photos/87442173@N07/8006792700/in/photostream/ Here is another one...tks

Pat wrote: I don't know the answer, but I have a bit of a follow up question....even as they harden, can tire treatments soften them back up a bit? Something like Formula V? I've never used one but have heard some positive results. Any feedback?

Yeah those things do work. I've used WD40 before but the mistake I made is that I did the treatment too close to the event and I think there was still some oily residue on them. Later on there was a noticeable improvement in grip. Just keep in mind that it will make the tire wear faster and make it more likely to suffer some kind of catastrophic wear - it should be saved for getting a little more life out of nearly-done tires.

In reply to guillespeed:

Hahaha no you can't drive on that thing! Sucks that you trashed your tire but it's done for now.

Oh man.....What a shame..........however it is all part of the learning process. My pocket is already bleeding. Thank you for your help Boy. Next time I'll think twice before going up to 150MPH....