andrewdr

Can the tires heat cycle out yet tread still remain? My tires were very slippery all day at Homestead yesterday, pressures were all adjusted to 37/38 rear yet there was excessive throttle oversteer. All settings, toe, camber, etc were fine at Sebring three weeks prior. As the tires became hotter they became more slippery.

Land Jet

How many heat cycles are on them?

andrewdr

If a heat cycle is considered one session on the track, "cold to hot to cold", then i had about 9 or 10 going into yesterdays event.

997gt3north

- they should last longer than that for sure but yes r888s can heat cycle out
- i had a very similar experience - car got crazy loose - even managed a near wot 3rd gear snap rotation off (car came around so fast i didn't even have a chance)
- got home, inner edges of rears were definitely worn (car was only running -2.3 rear camber - these tires don't need as much camber)
- new tires - car back to normal - i did soften the rear bar just to make sure however

rlm328

Is the 37 to 38 psi cold or hot temp? Hot inflation is 32 to 38 hot with 2.5 to 5 camber and an operating temp between 160 and 220 (from Toyo's Website)

Weston

Yes, R888's can and will heat-cycle out while there is still plenty of tread left. If you're lucky, they'll last beyond 10 road course heat cycles, but they'll be starting to go. By 20, they'll be total garbage, and it's not uncommon to have plenty of tread left. This has happened to countless racers and the difference is huge... it was a very consistent 2-3 seconds slow at Miller (outer track) for my 944-Spec. We're switching back to RA-1's.

LDadrenaline

could just be different rubber on the track, lack of rubber on the track, or even just the cold weather. I know at Sebring this past weekend my tires felt like garbage. One of my friends thought his R888s were getting old as well, but all it took was a little pushing and he set a new fast lap. There are a lot of things that can affect grip level, many people throw out tires too fast.

multi21

The answer is "Yes". These tires heat cycle to death prematurely, often times when just over 50% of the tread is gone. I'll never buy another set again.

J richard

This is what makes these tires so frustrating, they go to crap with all kinds of rubber left... Just this weekend I couldn't let go of the fact that a set of 888's looked great and evenly worn, with about 16 heat cycles on them, the car was all over itself, and lap times went way up after the first few laps, put on a set of 10 heat cycles and gained a second, put on a set of old RA1s and picked up two seconds over the old 888's, but almost more importantly it was so easy to drive with the RA1's to get better times. Its hard to look at all that rubber and chuck it but they really do turn to snot with plenty left...

RonCT

My R888s didn't really come into the zone until they had 8 cycles and I drove them for another 8 before selling the wheel and tire package. Also went back to RA1s and ran the rest of the season on them.

TedA

Anybody have any comments regarding the 888 needing less negative camber than the RA1s? Big fan of the RA1s over the years in terms of overall wear and grip thru their lifetime.

RonCT

Can't say really, but I have -2.4 degrees and both the R888 and RA1s worked well for me on this heavy car. Mine is set up for "DE / Street" as it's my dual-purpose P-car.

LDadrenaline

R888s have a stiffer sidewall and therefore you don't need to run as much negative camber. I read it somehwere in a press release from them.

mjensen

I have lots of data on R888's. I race a SpecMiata in SCCA Nationals. Here's our tire setup:
1 heat cycle on new shaved tires(2 or 3/32)
let heat-cycled tire sit for AT LEAST 24 hours
by the 4 to 6th heatcycle tire is at its best
10 to 14 heat cycles are to be expected but lap times/grip will suffer
Camber has been decreased, minor, run -4.0 front/rear on RA1s, -3.5 front/3.75 rear
Stiffer sidewall, helps in braking stability

Comparing to RA1s,
RA1s "slide/squire" a little more due to soft sidewall
RA1s will be consistant until corded(actual, not exaggerated)
Lap times between to 2 tires with appropriate adjustments are close

My opinion,
Run RA1s at DE/track day events due to consistancy and life expectancy

TedA

Edzachary. Also tire pressure variations react differently.