Tires

[Adair]

Atlantic board has been kind of slow lately. Would anyone care to share their opinion as to what is the hot tire choice set-up for an RT-41? Goodyear or Hoosier, bias ply or radial?

[Stan Clayton]

If your Ralt has 13" wheels, I'd recommend you stick with the Hoosier R-25A bias ply tires. These have been very good for us at track temps up to 115 degrees F. Above that, switch to R-35A's. We have never tried the Avon radials, but we have run the old (1990's) Goodyear and Yoko radials with good results. However, neither is in production any more and my tire man says the new Goodyear radials won't be available until later this year, so I can't recommend a 13" radial at this time.

If you are using 15" wheels you have an additional choice. If you stick with bias ply tires I recommend moving to the Hoosier R-35A compound any time the track temp is over 90 degrees - possibly even lower. There is something in the construction (sidewall stiffness?) which causes the R-25A's to blister at the slightest provocation on 15" wheels, so I do not recommend them. (If anyone is willing to share their counter thoughts on this subject I would love to hear from them.) The Goodyear radials are pretty good, too. Just be prepared to do extensive testing to find how they work with your car.

FWIW, the Ralts were designed for 13" radials, and we found that using 15" wheels resulted in a slower car, no matter the tire. So, for right now IMO your only real choice is the Hoosier bias ply. When the GY 13" radial appears it will be worth a set of tires and a test day to see how they work. Their 15" version is a very good tire, but that doesn't always mean that a different size will work as well.

Good luck! Stan

[Tom Szelag]

Track temp 115.. what instantaneous (or even post-lap) tread temps are you looking at?

[Stan Clayton]

Tom,

The 115 degrees track temp corresponds to a post hot-lap (car driven hard until right at pit-in) peak tire temp of 220 degrees F on our Ralt RT-41 on 13" wheels. We have tried to use R-25A's above that track temp, naturally, only to have them blister and throw chunks.

The ride's good while it lasts, though...

Stan

[Paul LeCain]

I know just about no one else uses them, but we used Goodyear 175s all last year. At Lime Rock, Goodyear measured the temps at 240-245 left side, 220-225 right side after a hot lap. The air temp was about 88 degrees. That was during qualifying.

The tires lasted the race, at slightly lower temps, just fine.