Wheel and Tire sizing

KevinBoosted · Jan 15, 2010

I'm just about ready to order some track wheels but dont know what a proper wheel size would be to the tire I want to use. I'm 99% sure the wheels will be 17" Rpf1s, and I want to run a 255 R comp tire but what size wheel should I use so it doesn't look stretched...17x8.5? 9? My fenders are getting rolled so fitment shouldn't be an issue but I'm unsure on offset. Thanks

D_Eclipse9916 · Jan 15, 2010

255 R compound? good luck. Most ive fit in an R is 245 and that was...uhhh already interesting.

I beleive Scott Mcintyre has 275s, you can check out his setup.

awdfun · Jan 15, 2010

I'm on 17x8 with 245 RE01R's with a +38 offset. No rubbing but not much clearance left.
Up next will be a 17x9 +35 on 245 R comps, and most likely have to run ~5 mm spacers in the rear to clear the 2ga rear suspension arms.

If this car ever gets stripped and caged...then I'll worry about wheels that need fender flares.

KevinBoosted · Feb 10, 2010

Well im still confused but want to see the difference in offsets in a picture. Im thinking a 17x8.5 with a +30 offset and now im thinking maybe 245 r comps wouldnt be such a bad idea

id still like to fit a 255 though...wider is better :thumb:

knochgoon24 · Feb 10, 2010

Here's this for a starting point.
http://www.dsmtuners.com/forums/fre...tions/286685-will-these-wheels-tires-fit.html

The R comps will be a bit wider than the 255 listed.

snowborder714 · Feb 10, 2010

I like to refer to this site when picking out larger wheels/tires. According to it, a 255 tire should fit. But as Wes pointed out, the section width (width measured at the sidewalls) will be wider than the advertised width. For example, the section width of the Star Spec 245's is actually 248.92mm.
wheel_tire_fitment_FAQ

When looking for tires for my Evo 8 wheels, I used this thread and made an Excel spreadsheet to do the calculations for me based off of any tire I input. Then I can see how much space I'll have left near the fender and the knuckle.

KevinBoosted · Apr 20, 2010

^ Thanks. I think im gonna give some 245/40-45 street tires on my evo 8 17x8 first. If it fits well i might go with a 255 after i roll the fenders some

snowborder714 · Apr 20, 2010

I put 245/40 Star Spec tires on my Evo 8 wheels and test fit them the other night. At rest, I have no clearance issues, even with the 2ga rear knuckle. I have not ran the car on them yet though so I don't know if I will experience any issues.

You can see my calculations here, and I might even have the 255 calculations if you want them.

greengoblin · Apr 20, 2010

Is there a big difference from the 2ga and 2gb knuckle?

snowborder714 · Apr 20, 2010

Enough of a difference that some tires fit the 2gb that don't on the 2ga. I have yet to see any hard evidence or numbers on what might fit and what won't.

I might be able to get some measurements this weekend of those Star Specs on my car vs. my brother's car ('99 GSX) to see what the clearance differences are.

knochgoon24 · Apr 20, 2010

My Evo 8 wheels and a set of Dunlop Star Specs 245/40/17 are now sitting at the tire shop. They should be mounted sometime today. I might throw them on the car later this week. I'll take some pictures.

greengoblin · Apr 20, 2010

snowborder714 said:
Enough of a difference that some tires fit the 2gb that don't on the 2ga. I have yet to see any hard evidence or numbers on what might fit and what won't.

I might be able to get some measurements this weekend of those Star Specs on my car vs. my brother's car ('99 GSX) to see what the clearance differences are.

Neat, post up what you find.

turbo addict · Apr 20, 2010

knochgoon24 said:
My Evo 8 wheels and a set of Dunlop Star Specs 245/40/17 are now sitting at the tire shop. They should be mounted sometime today. I might throw them on the car later this week. I'll take some pictures.

that would be great. I have the same car 97awd talon and wheels (evo) and want to run those tires either 245-40 or 255-40 17 so pics would be very helpful!

shleppy · Apr 20, 2010

the 2gb spindles only give you 3mm extra clearance, but with +35mm backspaced wheels the problem is the fender clearance, not the spindle. Rolling the rear fender wouln't cut it-you'll have to cut out the inner fender lip. When I rolled my inner fender lip it still cost me around 10mm vs cutting it out.

UofACATS · Apr 20, 2010

shleppy said:
the 2gb spindles only give you 3mm extra clearance, but with +35mm backspaced wheels the problem is the fender clearance, not the spindle. Rolling the rear fender wouln't cut it-you'll have to cut out the inner fender lip. When I rolled my inner fender lip it still cost me around 10mm vs cutting it out.

Whats your wheel/tire setup?

shleppy · Apr 21, 2010

255/40/17 starspecs w. 17x9+35 rpf1s-I really had to hack and roll outer rear fenders.

turbo addict · Apr 22, 2010

shleppy said:
255/40/17 starspecs w. 17x9+35 rpf1s-I really had to hack and roll outer rear fenders.

I would like to see your pics too if you have some. thanks

snowborder714 · Apr 26, 2010

greengoblin said:
Neat, post up what you find.

Here's the data Kevin.

Wheels:
Evo 8
17x8
+38 backspacing

Tires:
Dunlop Direzza Z1 Star Specs
245/40R17
Section width - 248.92mm

Calculated rear knuckle clearance:
5mm

Measured rear knuckle clearance:

Brian's car (1995 Eclipse GST)
Suspension - Tein Flex coilovers set to recommend Tein specs
4mm clearance

Eric's car (1999 Eclipse GSX)
Suspension - stock
9.5mm clearance

I can/will remeasure after we both have similar suspension setups (DG suspension with DIY camber kit) in the rear. I'm not sure how much this would affect the measurement, but I'd like to make the knuckle the only variable.

knochgoon24 · Apr 26, 2010

^^^ And here are a few photos...

Old 215/50/17 tires on 2gb Talon rims (17"x6.5" +46mm)

Rear