Heat Cycling of R888
11-30-2009, 11:03 PM
#16
Race Director
mjensen, thanks for the info. I have ben running R888's for my DE and am on my 2nd set in 16months.
My current set still has tread on the front but the rears are like slicks and wore out. I was wondering if my fronts are heat cycled out anyway. I drive 97miles to and from my DE events and I have 13 DE days on them. Think the fronts are toast too. I have a feeling they might be.
I ran RA1's on a 2007 Carrera S but wanted a stiffer sidewall but am thinking of going back to RA1's for something different and because they last so long. I just remember they squired so much especially trail braking I never had cofidence with the RA1's until around my 6th DE day or so...and that can take awhile to reach.
My current set still has tread on the front but the rears are like slicks and wore out. I was wondering if my fronts are heat cycled out anyway. I drive 97miles to and from my DE events and I have 13 DE days on them. Think the fronts are toast too. I have a feeling they might be.
I ran RA1's on a 2007 Carrera S but wanted a stiffer sidewall but am thinking of going back to RA1's for something different and because they last so long. I just remember they squired so much especially trail braking I never had cofidence with the RA1's until around my 6th DE day or so...and that can take awhile to reach.
11-30-2009, 11:05 PM
#17
Race Director
With RA1's I was told I should be running close to -3 front and -2.8 rear...WOW that would suck on the street.
12-01-2009, 12:09 PM
#18
Rennlist Member
There are products that will rejuvenate heat cycled tires, I got a link from a race buddy a couple of months ago, but I can't find it now. If the product does half of what it claims to do, it's worth trying. One liter cost around $30, and should be plenty for 4 tires. It is a petroleum based product, that you apply to the tires a couple of days befor you race. The product re-arrange the molecular structure in the rubber back to its original form (before the heat cycles). Supposedly you will have "new tire grip" all the way to corded tires.
A proffesional race driver told me he used acetone to soften up heat cycled tires (for practice laps). He soaked the tires in acetone, and put them in black trash bags for a while, before he used them. He said that this really softened up hardened rubber.
I haven't tried any of these methods, but it would have been interesting (and cheap...) to give it a try.
A proffesional race driver told me he used acetone to soften up heat cycled tires (for practice laps). He soaked the tires in acetone, and put them in black trash bags for a while, before he used them. He said that this really softened up hardened rubber.
I haven't tried any of these methods, but it would have been interesting (and cheap...) to give it a try.
12-01-2009, 12:21 PM
#19
Rennlist Member
mjensen, thanks for the info. I have ben running R888's for my DE and am on my 2nd set in 16months.
My current set still has tread on the front but the rears are like slicks and wore out. I was wondering if my fronts are heat cycled out anyway. I drive 97miles to and from my DE events and I have 13 DE days on them. Think the fronts are toast too. I have a feeling they might be.
I ran RA1's on a 2007 Carrera S but wanted a stiffer sidewall but am thinking of going back to RA1's for something different and because they last so long. I just remember they squired so much especially trail braking I never had cofidence with the RA1's until around my 6th DE day or so...and that can take awhile to reach.
My current set still has tread on the front but the rears are like slicks and wore out. I was wondering if my fronts are heat cycled out anyway. I drive 97miles to and from my DE events and I have 13 DE days on them. Think the fronts are toast too. I have a feeling they might be.
I ran RA1's on a 2007 Carrera S but wanted a stiffer sidewall but am thinking of going back to RA1's for something different and because they last so long. I just remember they squired so much especially trail braking I never had cofidence with the RA1's until around my 6th DE day or so...and that can take awhile to reach.
I have 888s on my 986 and got about 15 days out of the set with my wife also driving a few of those days. Thus the heat cycles on the tires were probably up in the 40s! I had a massive decrease in grip in my last two days of the season with those tires (which was actually sort of fun since I do DE and not racing!).
I don't think this first set of 888s felt 'right' until about 10 heat cycles, then I liked them.
I do not buy them shaved or cycled.
12-01-2009, 12:52 PM
#20
Racer
Join Date: Nov 2006
Location: Arvada, CO
Posts: 387
Likes: 0
Received 0 Likes
on
0 Posts
There are products that will rejuvenate heat cycled tires, I got a link from a race buddy a couple of months ago, but I can't find it now. If the product does half of what it claims to do, it's worth trying. One liter cost around $30, and should be plenty for 4 tires. It is a petroleum based product, that you apply to the tires a couple of days befor you race. The product re-arrange the molecular structure in the rubber back to its original form (before the heat cycles). Supposedly you will have "new tire grip" all the way to corded tires.
A proffesional race driver told me he used acetone to soften up heat cycled tires (for practice laps). He soaked the tires in acetone, and put them in black trash bags for a while, before he used them. He said that this really softened up hardened rubber.
I haven't tried any of these methods, but it would have been interesting (and cheap...) to give it a try.
A proffesional race driver told me he used acetone to soften up heat cycled tires (for practice laps). He soaked the tires in acetone, and put them in black trash bags for a while, before he used them. He said that this really softened up hardened rubber.
I haven't tried any of these methods, but it would have been interesting (and cheap...) to give it a try.
12-01-2009, 04:40 PM
#21
Race Director
interesting...I have nearly 30 heat cycles on my R888's (started with full tread) and I would say they are 50%+ treadwear left...& the grip seemed fine....but I wasn't pushing the car very hard either.....
12-01-2009, 07:20 PM
#22
Racer
Join Date: Nov 2006
Location: Arvada, CO
Posts: 387
Likes: 0
Received 0 Likes
on
0 Posts
I would use dead R888's for general track days, as they should still be better than street tires, and there's plenty of rubber left to wear down. But they are simply not competition tires after much more than 10 heat cycles, and that limits their value as practice tires as well. They're frustrating if you're going to drive them at 10/10ths, but probably fine if you're just screwing around.
12-01-2009, 07:55 PM
#23
By all means there are numerous factors here. Even with the tires shaved to 2/32 or 3/32 we will heat cycle them out before the tread is completely gone. The R888 is also more tire pressure sensitive than the RA1. One the Miata we run 36 to 38 hot on RA1's and have been running 32 front/36 rear. Other SM guys are running 42 hot, and have heard as low as 26 hot. I ran R888's on my 944 SVRA car, 3/32's 36 hot and had excellent grip. One word of caution is that the particular tire difference is the sidewall stiffness. So on the Miata, guys were RAISING the overall tire pressure to actually higher than reccommended to help the car slip and rotate, basically creating the feel of the RA1. What I found out that when I ran a lower psi I had gained grip, consistant heat and longer heat cycle. The tire would be consistant from lap 1 to the flag. This is my experience and just use this as an opinion. I agree with Weston...
