tinnerman88

I have an xB with ICW 786 rims.The wheels are 18" diameter w/ 42 offset and 35 series tires on 'em.My box is also lowered roughly an inch courtesy of TEIN H-Tech springs.....What I wanna know is can I squeeze 40 series tires on the wheels?If anyone has this set-up,can you let me know how its workin out?

Iheartdabox

I have the TEIN ss w/pillow mount and I run 40 series on 18's. I'm dropped way more than what you are and the only time I rub is when I hit a serious....and I mean serious bump on the freeways. So IMO, you could do it.

psyawnexbea

40 series tires on 18" rims actually gives you a diameter that is closer to the stock rim/tire combination than 18" rims with 35 series tires (so long as go with a tire that isn't very wide; i.e. 215/40/18 If you go with a wide tire like 225 or 235, you still shouldn't get rubbing, however it will raise the car noticably. Also, if you ever decided to run s-techs, you could run into rubbing issues with the wider tires.

RTon20s

This is absolutely not true. The calculated diameter of the stock tire is 23.74. The calculated diameter of a 215/35/18 is 23.93. Moving up to a 215/40/18 bumps the diameter up to 24.77. That is a full inch larger than stock.

Now if you take into consideration that the stock JDM tire (and speedometer and odometer calibration) is 185/65/15 you get a diameter of 24.46. Even then the diameter of even the narrowest 40 series tire on an 18" wheel exceeds the JDM stock limit. Moving to a wider tire in a 40 series will only make the discrepancy greater.

So is this to say you shouldn't run a larger tire? No. The car can handle it, and the speedo and odo won't really be much further off than it already is with stock tires. Just keep in mind that the more you unsprung weight you have, the worse off you are. And the larger your tire diameter, the more work it is for your engine. For many though, the added "security" of a 40 series tire is worth it.