Any specific reason why most people end up with 235/315 combo when upgrading? I know that's the factory GT2 size, but it seems that 335 would fit just as well. Can 245 or 255s fit in the front? an 8-8.5" front rim should be able to support that with the right offset.

I know from experience that too much stagger can result in understeer. So I can see why you don't want too much rear tire if the fronts can't be upgraded as well.

 

A 255/30/19 in the front would be a better fit with a 315/25/19 rear than a 235/35/19.

This tire size calculator has really helped me over the years:

http://www.miata.net/garage/tirecalc.html

Specification Sidewall Radius Diameter Circumference Revs/Mile Difference
225/40-18 3.5in 12.5in 25.1in 78.8in 804 0.0%
235/35-19 3.2in 12.7in 25.5in 80.0in 792 1.6%
255/30-19 3.0in 12.5in 25.0in 78.6in 806 -0.3%

Specification Sidewall Radius Diameter Circumference Revs/Mile Difference
295/30-18 3.5in 12.5in 25.0in 78.4in 808 0.0%
315/25-19 3.1in 12.6in 25.2in 79.2in 800 0.9%

 

335/30-18 should fit with proper wheel offset. They're 26" tall and matching front tires have a problem with clearance. You could probably run 335's on GT2 rear wheels with a 1/2" spacer. The sport techno factory spacer might work.

 

what do you need for 255s in front?

 

I think you also have to consider the ride height and camber for the 335's in the back. And throw in a fender roll like the GT2 has for good luck!!

 

I can't seem to find a 335/25/19 tire size for sale anywhere...

 

335/30/18...

 

Ruiner I have the 12" wide GT2 rear wheels with the 315/30's, ya think that 335 would fit? Of course my feelings about tire size is if it isnt rubbing a little its not large enough!!!!

 

I be they would. That's an expensive tire to try, especially if it doesn't fit! Someone has to have tried!

Tire Rack?

 

i tried 335 conti sports and they did not fit... i have 12 inch rim but its on a 19 inch wheel.... I also have pss9s

 

Do you know the offest of your rear wheels?

 

the offsets are 34 mm in rear and 41 in front. 4.5 inch lip.
cargraphic racing 3 piece wheel.

 

RUF R Turbo 550

We have 265 / 35 / 18 front. Record?
315 / 30 / 18 rear.

ET 40 mm front and rear.

No spacers.

Center bolt from Cup car

 

They might fit if you drop down to a 25 profile, but good luck running that at the track! A 25 profile will do nothing but hurt you in the corners. As for a 335/30

The problem that you face is two-fold:
1. You need to keep the front and rear tires w/in a certain % of each other in terms of revs per mile in order to not fry the differential.
2. If you go larger (or smaller) on your wheel's radius (or circumference), you will affect your speedometer as well.

Here is a selection of rears on an 18" wheel for you. Depending on what you run on your front, your rear may or may not work in terms of your differential (what size do you run on the front?):

Specification .. Sidewall . Radius . Diameter Circumference Revs/Mile Difference
295/30-18 ..... 3.5in .... 12.5in ... 25.0in ... 78.4in .......... 808 ....... 0.0%
315/30-18 ..... 3.7in .... 12.7in ... 25.4in ... 79.9in .......... 793 ....... 1.9%
335/30-18 ..... 4.0in .... 13.0in ... 25.9in ... 81.4in .......... 778 ....... 3.8%
335/25-18 ..... 3.3in .... 12.3in ... 24.6in ... 77.3in .......... 820 ....... -1.5%

 

There isn't one. At least the from the brands that we carry.