Heat Cycling

[TheStig]

So I've made the decision finally, these H-rated tires on my car are making me shout R-rated words with their lack of sticking to the pavement. I found a nice set of Kumho V700s that would be a great improvement for the track. Only issue is heat cycling. Since I don't push my car too hard on the track, would I still need to heat cycle to extend the life of the tire? Has anyone on here heat cycled or not heat cycled their competition tires or any tires with treadwear less than 50? How many track days have you gotten out of your use of your competition tires? Opinions are welcome!

[bibbetson]

If you are not pushing too hard, then your first event will effectively heat cycle the tires. Heat cycling basically strengthens the rubber molecules. As long as you don't tear the tires up the first time you use them then you can skip the expense of heat cycling. I have run dozens of sets of R tires both ways and I believe that each tire reacts differently. In my experience Kumho's like heat cycling.

[TheStig]

thanks!

Now for tire pressures. I've been told to run 36 all the way around to start. But R-compounds are very different than street tires. What are your 924s 944s and 968s running cold on comp tires?

[bibbetson]

Again, it depends on the tire. I always had good luck starting out using the Porsche recommended tire pressure. From there, the only way to really know is to use a probe pyrometer, or get someone to recommend pressures with a nearly identical car/tire setup. Otherwise you won't know except with a lot of experimenting. For example, my 968 pressures are useless to you because the tire size, weight, alignment, etc. are totally different then your car. Do yourself a favor, get or borrow a pyrometer so you don't toast a set of tires. Remember, R tires are great, but when pushed outside their envelope you can trash them in a day.

[Jad]

Bill is correct, but 38-40 lbs hot is a good rule of thumb for the Kuhmo's. Watch wear, check the feel for oversteer and understeer and if you can't tell, you probably should be saving your money and blaming the driver not the tire. I have no idea how you drive, so don't take it personally, but as a rule, if you have to ask, you probably aren't ready. The $600 bucks you spend on tires would be better spent on a weekend at Willow or a couple of QDE's. You will be faster, have more fun and learn to drive, not spend money on your car. Of course, I make this lecture often and others believe in perfecting the car, and then learning to drive it.

IF you decide on R compounds, I would recommend the Toyo RA-1's. They last ~3 times longer than the V700, don't need heat cycled, but should be shaved and give you a similar tire to the spec 944's which are a good target to measure your driving skills (plus are arguably faster than the Kumhos.

Good luck.

[TheStig]

Jad I totally agree with you and accept your constructive criticism. I probably am not ready as this most recent auto-x was only my third one. Perhaps I should stick with street tires for now, but go to a more improved tire such as an ES100 to practice off of. At least that has better grip than what I have now. The Sumitomo HTRs are murdering I do need a lot more seat time and I don't have the adequate skills so many others out there have right now. I guess it's just more of a time factor than mod factor.

[bibbetson]

If this is just your third AX, then I would definately recommend you go with a better street tire. I really like the ES100. They aren't quite as fast as some others, but they are quick and very inexpensive. There certainly are other choices, but something in that ballpark is a really good choice. You will feel like you are on race rubber compared to what you have now.

[TheStig]

yea Bill you really hit the nail on the head, you might as well give me bicycle tires. I'm sure those will handle better than Sumitomos

[TheStig]

ok tomorrow I'm gonna go check out some ES100s at Discount. As you can see I also have insomnia.

[harnishclan]

There is a pretty good article in Grassroots about different DOT tires and R compound tires that you might want to take a look at. I am about a year ahead of you on this slippery slope and have been using yoko ES100's. Grip is good enough for driver skill and wear is really good. My 944 is pretty close to stock with the exception of weight removal, 250# springs, 25.5 mm front sway bar, welmeister 22mm rear sway (set at soft). Alignment is stock except for an additional 1/2 degree of neg camber in the front. I had a ton of oversteer until the addition of the rear sway bar, and now I simply have way too much. Tire pressures are 39.5 in rear and 36 in front. I am about 3-4 seconds slower than Jackie with this setup. I think it is better to use tires with a little slip in them because it teaches you how to control it better. R tires hold until they let go (for the inexperienced), but street tires give a little warning.

[Jad]

Sounds like a good choice, I had the ES100's on my Boxster and like them. They do pretty well on the track and you won't kill yourself when you drive on the street and hit a puddle or something. Much softer ride as well....

Plus, the 4 points for the R-compound would kick you up to GP and you wouldn't have too many people with similar times to play with like you do in GS.

The good/bad part is, there is always someone faster, whether they are in your class, or someone like Steve G. But, while Steve does well at AX's, there are faster people/cars at big tracks, who are slower than the more professional teams, which are slower than the top teams, which are slower than the higher classes, etc. Unless you are M. Schumacher LAST year, then it is a never ending struggle to be faster. I give up and just find a fun group of people to race with and just modify the car enough to compete with the group. It is more fun for me to do a 90 second lap battling 4 people than an 80 second lap by myself.

Enough procrastination, I guess I need to work now

[TheStig]

WOHOO I got me some ES100's today during lunch!!! Can't wait till they arrive at Discount!