Tire Size for AutoCross

[SgtRauksauff]

Hey, I'm buying new tires all around right now, very much needed ones, too. I'm trying to decide between 2 tires.

On my stock EscortGT rims (15x6.5), I'm getting some Kuhmo ECSTA Supra 712's. I'll probably run those rims/tires on the wagon while the GT is in its project-build-up status. Which would be better for autocrossing, 195/45-15, or 195/50-15? I know the /45s would make for a slightly smaller diameter, and shorter sidewall, and thus stiffer tire, but is it too much? Would I be better off going with the 195/50's instead?

Currently on the EscortGT are some ICW Racing rims, I think they're 15x7, but I haven't had the tires off yet to check. But they need to come off badly, since they're 215/65's and are heinously too tall. But, they were with the car when I got it, so I can't complain. New tires for my brother's buick, thats all. Would a 205/50 be a good tire on those ICW rims, or would it be better to put another set of 195/50 or /45's on them?

I'm thinking i'd like to use the ICW rims for racing, since they're supposed to be light (haven't weighed them yet) and I've been highly recommended the Falken Azenis Sport tires for autocrossing. But, I've heard that the Kuhmos kick arse too.

So, which Tires (or both, to find out for sure which are better)?
And, which sizes?

I bow before the amassed guru-hivebrain-knowledge of this board's experienced racers.

--sarge

[Mazdaracer]

Well, i started on the Kumho 712s and they are OK, really good in the wet mind you, but they are no Azenis! It's a night and day difference. And the Azenis are cheaper than the 712's.

for a street tire i would stay as close to OEM size as possible for mileage reasons and if you go too small on race tires, (or any tire for that matter) you'll thro off the grearing.

I run 205/50/15 Azenis on 15x7 wheels w/35mm offset for racing and 205/45/16 712's on 16x7 w/42mm offset wheels for street.

I would suggest the 205/50/15 for both street and race. But a 195/50/15 would be ok for street too. For racing you want as much tire on there as you can get.

[SgtRauksauff]

thanks! My 205/50 Azenis' are on the way for the 15x7 rims ( I hope the offset doesn't screw with me too bad. I'm not sure what it is yet, as I haven't been able to identify what model of ICW rims they are. :/

I'll probably get the 195/50 Kuhmos for the stock 15x6.5 rims, and run those daily and in races when it's wet outside, otherwise sticking to the Azenis' for racing when its dry.

---Sarge

[blu]

having your speedo off a little isn't that big of a deal, as long as you are aware of it and compensate accordingly. YMMV.

miata.net has a good tire-size calculator i use a lot.

[PseudoRealityX]

I believe you're mistaken with the width of oem Escort GT alloys. I HIGHLY doubt they are 6.5". I'd guess either 5.5" or 6".

[blu]

oem egt wheels are all 5.5" (91-96)

[SgtRauksauff]

well, I guess I assumed that they were wider than my 14" ones by more than they really are.

doesn't really matter, the 205's are going on the 15x7's, and I'll be getting 195's for the oem rims most likely. But thanks for the clarification!

--sarge