What Tire Size??

[prine68]

I just received my new Rushforth Livewires, I can't wait to get them on. My question is what is the best tire size for the rear, the front are 18x8 with 4.875 b/s and plan on going with 235/40, and the rear are 18x9 with 5.25 b/s. I had 17x9.5 and had 275/40's and had no issues, can I keep that size or should I drop down to 265/40's?

[JustinB]

245/40/18 and a 275/40/18.

[Taman]

If you have the extra 1/2" clearance issues near your wheel well lips, go for it. If you do, go to a 35 series tire. You live near me. I am at 90 and Randall rd. Drive over and you can bolt my rims up. 285/40/18. If they fit so should 275's. I have 245/40/18 on 18x8's.
https://static1.pt-content.com/images/pt/2010/06/photo-1.jpg

[prine68]

I had 245/45's on my 17x8 wheels with 4.75 b/s and had rubbing issues on the outer fender so I went with the 235/40 and they worked great. I'm a little worried about trying the 245 size again. Would the 4.875 b/s on the Rushforth's push the wheel out more or bring it in a little. All this b/s stuff confuses me. Thanks for the offer, if it comes down to that I might take you up on trying your wheels on.

[Taman]

It's worth the time before you buy tires. Bs space is measured from the backside lip to the mounting pad. So, the more back space the closer in the tires. Less back space pushes the tires out giving more inside clearance.
Offset is measured from the center of the rim in millimeters. A 8" rim with a 4" backspace would be 0mm offset. After that its positive or negative the amount different from center.

[alowerlevel]

Try playing around with this for a bit, should give you a better idea of everything http://www.rimsntires.com/rt_specs.jsp