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How wide of a track tire can you go and keep heat

Posted: Sun Oct 22, 2017 10:25 pm
by maurice
Hey guys, I'm looking for some help with picking a tire size for track use. I live fairly close to Sonoma, and I bet my roommate that if my bug can beat his tracked out m3 around the track, he had to sell it.

Anyway, I picked up some new wheels with bad tires, and I'm able to fit the old 275-40-17 rear and 235-40-17 front tires under my fenders with plenty of clearance. I'm thinking of using toyo ra1/r888, Michelin pilot powers, or other streetable sticky tires. But my worry is that my car will be too light to keep heat in the tires.

The car is a 66 bug converted to IRS, big brakes, polyurathane bushings, sway bars, jdm wrx engine with ~280-300hp to the wheels, bus tranny etc. my plan is to go mid engine this winter so I can run a 5/6 speed Subaru tranny and get some weight over the front. Also building a much more powerful engine - however I may only turn it up for drag stuff.

Currently I'm running some 275-60-15 drag radials rear and little 185-50-15's front, but I've mostly been having fun launching and drag stuff, not really cornering since the little tires like to under steer.

I'm open to doing auto-X but my main goal is Sonoma, thunder hill, and Laguna.

Any suggestions? :)

Re: How wide of a track tire can you go and keep heat

Posted: Mon Oct 23, 2017 5:11 am
by dlamyle
maurice wrote: Sun Oct 22, 2017 10:25 pm I bet my roommate that if my bug can beat his tracked out m3 around the track, he had to sell it.
Any suggestions? :)
Yes. Don't give the German's 50 years to design a much better performance car and then challenge a track prepped example to a race. :wink:

Re: How wide of a track tire can you go and keep heat

Posted: Mon Oct 23, 2017 7:54 am
by ChadH
If he doesn't respond directly, read though some of FJCamper's threads. He posts of wealth of information and insight. Below is one, there's others in STF too.

http://www.shoptalkforums.com/viewtopic ... 1&t=127619

It looks like his attached photos have fallen victim to Photobucket though. :(

Re: How wide of a track tire can you go and keep heat

Posted: Mon Oct 23, 2017 8:43 am
by maurice
dlamyle wrote: Mon Oct 23, 2017 5:11 am [quote=maurice post_id=<a href="tel:1254998">1254998</a> time=<a href="tel:1508736338">1508736338</a> user_id=40042]
I bet my roommate that if my bug can beat his tracked out m3 around the track, he had to sell it.
Any suggestions? :)
Yes. Don't give the German's 50 years to design a much better performance car and then challenge a track prepped example to a race. :wink:
[/quote]

Lmao, I told him that long after I decided I wanted to screw around on the track. At least I make about the same power he does with a little less weight...

I'll keep digging around. Some of the threads I've read limit their size because they're doing autox, the class they race in, or just physical space.

Re: How wide of a track tire can you go and keep heat

Posted: Fri Oct 27, 2017 10:10 am
by PhillipM
It's not just the heat, it's the extra weight, no point chasing fractions of a percent with wider tyres if you've just added 10lb of weight in the worst place possible.

Re: How wide of a track tire can you go and keep heat

Posted: Fri Oct 27, 2017 12:37 pm
by Ol'fogasaurus
Its also the foot print, the tire's material, the type of tire, the rim to foot print ratio and how the sidewalls are affected by the whole mix.