Advan Racing sizing advice

scammy · 6 July 2015

So I installed slightly larger front fenders and am looking to fill them out a bit more I run the Nitto NT01 235-40-17 with no major rubbing issues inside the wheel wells. A 245 tire would be preferred but I drive to the track on these and do not trailer the car so need a semi slick and Nitto do not make a 245-40-17 in the NT01 only a

[FONT=swis721_btroman]245/45ZR17[/FONT]

235/40ZR17

371100

6.3

24.40

9.49

8.0-(8.5)-9.5

1323

@

51

These are the Advan Racing RG3 rims I have on now with the 38 offset

17x8.0J	114.3	5	54	$603.00	$650.00
45
38

I am wondering for those experts that know would this size with the 31 offset fill out the new guards a bit more they are the preferred sizing for the Nittos at 8'5 inchs, so I am not sure how the extra half an inch affects the clearance inside the wheel well for rubbing at full lock and the extra 7mm of offset?

17x8.5J	114.3	5	51	$609.00	$656.00
31

I would prefer not to run spacers and dont want another complete set of rims the rears are a perfect fit so thought if I just get a better front size of what I currently run for my new fenders.
Cheers

whrdnsx · 6 July 2015

Gday Cam
I use this calculator for comparisons;

http://www.willtheyfit.com

nsxtasy · 6 July 2015

Yup. You'll have an extra 5 mm of treadwidth on either side, but if you're changing the offset by 7 mm, that means it will be wider (i.e. need more lateral clearance) by 12 mm on one side, but slightly narrower on the other side. Plus the calculated outer diameter of the 245/40-17 tire will be 1.3 inches (32.5 mm) larger than the 235/40-17, so the tread will be further from the axle by half that distance (i.e. radius rather than diameter).