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Hey guys, I arrived at the track this past weekend with a fairly new set of Cup 2's (maybe 800 street miles on them). I left the track with something other than new Cup 2's.
How do I estimate how much life these tires have left on them? I did around 12 laps, and the track temp was maybe 47 to 50 degrees. If I post some pics can anyone gestimate if I used 25%, 50% etc. of the useful life? Can I just measure the depth of the treads, or is there more to this?
I'd be surprised if you used more than 5-10%. You can measure tread depths, but be aware that without a track alignment, you probably wore the outside shoulders most. Also with track use, it's possible to wear out tires before the tread is gone (from too many heat cycles), but this is highly unusual for the stock tires which usually get corded before that...
They're probably fine unless you ran too much or too little pressure. They should be good for a pile of heat cycles (30+). They're just less pretty now.
I personally have never corded a set of Cup 2 tires as they loose grip long before the tread is gone. If you can tolerate the lack of grip run them to the cord. Your tires will not wear evenly no matter what your camber is set to. Each track has its own way of wearing tires out and usually depends on rotation. My advise is to rotate your tires often to even out the wear. Now pray for RE 71R's in 305's...
Sgroer runs bald tires at the track and he's faster than just about everyone so I wouldn't worry too much about it !! :P I believe tread really only comes into play when it's wet on the road, but someone will correct me if I'm wrong.
I think most track guys will see their tires heat cycle out before the tread is gone... I'm still running my stock wheels and original tires at the track and they grab as good as day one. That's three full track days (30-50 laps each day) and a lot of mountain driving. They don't look very good, that's for sure.
FWIW -- I am running a track alignment from Goldcrest Motorsports who seem to know what they're doing.
Though I only run on the street I do work them in the turns. Had to replace the fronts early due to rock damage. Then rears started to get loose before I hit the ware bars. They do heat cycle out. My fronts are now about 70 to 80 percent gone and still good.
In my experience with a street type alignment (2deg neg camber or less) Cup 2s have a common wear pattern. The large outside block wears faster and the second rib will have a beveled shape. They'll cord on the outside with plenty of tread in the center/ inside. Total life depends on lots of factors. For me about 19 to 20 Heat cycles or about 4 to 5 days is the limit. And the last day is a bit sketchy. First photo is 11 HCs, 2nd is 20 HC, last is from a GT4 but same tire at the end.
If you can get 30 heat cycles (otherwise known as individual runs) you're doing a pretty good job. And some instructors will tell you that as a beginner, you will learn more from a car that has a bit less grip. Let's face it, a GT3 is a cheater car, equipped with cheater tires, for a beginner. I have come to embrace that
I usually start thinking of buying a new set after about 24 or so.
In my experience, when I started out, my wear was pretty even across the tire, on all 4, which is a good indication that they were inflated properly, and I wasn't overdriving them. As I got better with corner entry and exit speed, I started wearing the front shoulders at a decent clip. It's fair to say that maybe I am NOT better, but that I am leaning on the tires more than I was before. I just swap the fronts left to right, and am good for a couple more events.
I find that the tires do well, when hot, running at 30lbs at the front, and 31lbs at the rears. YMMV. I will go run them near recommended for my first session, and then start letting air out as the day goes by. Then of course, refill them before I leave the track.
The way to tell definitively, is to buy a pyrometer, but for you, I think that's down the road a bit.
Though I only run on the street I do work them in the turns. Had to replace the fronts early due to rock damage. Then rears started to get loose before I hit the ware bars. They do heat cycle out. My fronts are now about 70 to 80 percent gone and still good.
I wish I lived in your neck of the woods. To be able to hear cycle out tires on the road.
Depending on whether your track is CCW or CW, you'll tend to wear the outside tires more. Hence swapping the sides every couple track days can help even out wear side to side.
I imagine tire pressure will make a difference as well. I can't remember if the chalk-across the tread is for camber or tire pressure but can be a decent hint if you're using all your tire's patch evenly.
03-14-2017, 12:13 PM
Understanding Tire Wear After Track Day
