R-compound tires for street: heat cycles & longevity: Grassroots Motorsports forum: Grassroots Motorsports Magazine

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June 24, 2008 7:24 a.m. NOSLO6 None

Hi folks,

I'm looking from some input on your experiences with running wide R-compound tires as drivers.

I've previously run Nitto 555R2s on my 2002 Z06 and loved them; good hot performance on the street or autocross, predictable wet behavior, long life. Their 555R drag radials were also wonderful on the Buick for the same reason and I used them for years before I started overpowering them (now use Mickey Thompson Street Radials which go great in a straight line and handle like poop).

I'm currently running Toyo R888s on my C6 coupe (19" factory rear wheels ruled out the super bang-for-buck Nitto) and but will be adding Z06 rear fenders, which open up some wider tire possibilities. I've been looking at the 345-30-19 Michelin Pilot Sport Cups and know these will take a bit more effort to come to temperature.

Interested in your thoughts on two things: (1) General feedback on folks' experiences with MPSCs on the street (I cycle to work and put about 3k miles on the car per year and can live with the limited tread life); and

(2) A little education for this long-time drag racer on # of heat cycles a R-compound tire can withstand and still be decent. Are there rules of thumb for the temp at which a tire experiences a heat cycle (180+ F?)? Is this temp value a simple threshold in the sense of once crossed for any amount of time the tires have been cycled, or to the tires need to be at temp for a certain amount of time? How many heat cycles might I expect to get (assuming no overheating)?

Thanks, any and all comments and links to good knowledge building stuff appreciated.

Cheers, Scott
June 24, 2008 8:43 a.m. Xceler8x Reader

I have a link discussing that right heah!

http://grassrootsmotorsports.com/forum/grm/ra1s-on-the-street/1207/page1/
June 24, 2008 8:46 p.m. NOSLO6 New Reader

Thanks X!

Any comments from folks on the heat cycle questions raised above?

Cheers, Scott
June 25, 2008 10:36 a.m. CivicSiRacer New Reader

There is a time where adding heat will release the mold release compound, and then the tire will be perfect for x number of runs then start to fall off.

It's hard to say what each tire is going to be. I know the Azenis need to be driven about 500-1000 miles to be perfect, whereas R1Rs are supposed to be perfect after scrubbing.

I personally wouldn't be driving my DOT R tires on the street except to scrub them in and get the mold release compound off. When you add heat to the tire you are effectively hardening the tire mile after mile.

The only tire that I remember that didn't drop off with more miles were my Yokohama A032Rs back in 2000. They stuck until they were corded. :)
June 30, 2008 9:08 a.m. NOSLO6 New Reader

Thanks folks-- any additional comments on the # of heat cycles issue?

Cheers, Scott
June 30, 2008 12:50 p.m. billy3esq Dork

RA1s don't seem to care how many heat cycles they've had (first hand experience). I've heard the same is true of the Nitto NT01s. Most other R-compound tires will eventually heat cycle out.