I took my car to the track for the first time last weekend at Roebling Road in GA. I had just put on some Kuhmo Ecsta MX 225/50/16's and only had about 300 miles on them prior to going on the track. Once the tires warmed up, I started feeling almost superhuman slinging the car around the corners. However, I progressively began to lose traction during the session came in. I assume that I had overheated the tires and was experiencing the "greasiness" that people have talked about. The problem was that when I went out later, I never seemed to achieve the same grip that I did initially. Are these tires still useable on the track?
Was it just my perception that they lost grip? All informed comments are apprecciated.

 

Those tires have been badly overheated and will never be the same again. You're not imagining things.

If you honestly plan to run those hard at the track (or nearly any street tire) you need to shave them first, but that set is already gone. A shaved tire runs cooler because it has less tread squirm and less rubber mass to hold onto the heat so the rubber doesn't overheat as easily and begin to break down.

Given the fact you were even able to do that to the tires you were pushing it pretty well, so pat yourself on the back

 

I ran those tires because I had read here that for street tires they had good grip and could tolerate some heat. With that feedback it sounds like an upgrade is necessary. What suggestions do you have for a tire that I can drive to a track and will last for a few sessions? Or would you reccommend just getting a trailer and another set of rims? I would like to keep costs down, but I must say that feeling like superman was intoxicating...
Mark

 

You can shave a street tire? I thought that was only done on the track tires...

thanks for the info....

 

They can but they still have their limits. You didn't overheat them too badly because they didn't begin chunking but they got too hot. In your case shaving them first will most likely take care of any future problems.

If you plan to track more than a couple times a year I would buy an extra set of wheels to mount track tires on. They don't have to be true R compound tires, but if you have different track tires you can shave them and manage them for track only use. I also recommending using a trailer because it would really suck to be on your way to the track and pick up a nail in your race rubber...

 

Only 300 miles on them without a good heat cycle first? Wow, those tires are toasty! My Toyo T1-S have been through 3 or 4 events, two of them above 90+F without any abnormal wear or heat issues. I tend to drive fairly cleanly though....but the fact remains that Kumhos are very cheap in comparison to other performance tires. You don't get something for nothing, so maybe the Kumhos just don't hold up as well under those conditions as a Toyo or other "high-end" tire.

 

There's more to it than just the tire brand. Any tire will begin to come apart if you overheat it. I've done it to new, unshaven R compound Victoracers by being overly aggressive on them when they were fresh and they only have a 1/4" of tread to start with!

How hard the car is run, the length of the session, the air pressure, the track surface, the temperature outside, the alignment etc all effect how hot the tire will run on any given day. Once the tire overheats grip begins to immediately fall off and the rubber tends to harden after it cools. That's why it's so important to not over drive the tires; you're just burning them up and not going any faster.

I'd say those tires in the pic are not junk, but they will not stick as good as they did before they were overheated.

 

Not to put you down, but technique/driving style has a lot to with the tire wear as well. Considering it was your first time out there, I'd say you are still at the beginning of a steep learning curve. Slinging the car into the turns is a perfect way to overheat them - ask me how I know

When I first started doing HPDEs I toasted tires like that as well. Same thing happened when I first started racing go-karts few years back. I was overdriving the car in the turns instead of driving smoothly and tires like that were the end result.

Consider getting another set of stock wheels and get another set of tires like those Kumhos or some Toyo RA1s for the track and shave them down some. You probably don't want to jump to slicks as they are harder to get used to if you have never driven on them before.

 

dude thats normal after going to the track.... the tires are not melting or anything of that nature... all the porcshe guys at work have a spare set when they go to sebring for the reason of the rubber that builds up on the track sticks to the hot tire as you race around. go and drive around on them and you will see that the rubber will come off... or pick it off. stop being a wussie...

 

I have no doubt that I was overdriving in the turns and have a long way to go in terms of learning how to drive. It wouldn't be any fun if it just took a weekend to figure out how to go fast. Thanks for the info, guys.
Mark

 

That is NOT rubber pick up. It's definitely overheated street tire. Tire overheats, rubber seperates and is moved fairly uniformly on the surface. Rubber pick up is random chunks of rubber on the surface.

 

Yep. It's obvious that the tire is failing because the tread is peeling away from the inner edges of the tread blocks which is the edge that wears when cornering. Rubber that is picked up looks nothing like that.