I just upgraded from the OEM Gen4 16" rims to 18 x 7.5s off an ’03 Infiniti M45. The original equipment Infiniti tire on this rim is a 235/45/18.

I'd like to run a wider tire but still stay reasonable as far as a change from the OEM overall diameter. The tire I’ve found to be most desirable to me is a 245/40/18.

In shopping for that size tire (245/40/18) I'm finding that the acceptable rim width is 8.0” to 9.0”.

What’s got me a little perplexed is the fact that in looking at some of the application tables for various tires, some state that the acceptable rim width for a 235/45/18 (the OEM size) is also 8.0” to 9.0”.

That being said and knowing that, in fact, the manufacturer put a 235/45/18 tire on a 7.5” wide rim, would everyone think it would be safe to install a 245/40/18 tire on a 7.5” wide rim?

 

i think it would be safe, but i wouldn't do it. 235 is pretty fat for a 7.5" by my standards (but i'm running 235 on a 9.5 so...).

i would just stick with 235/45.

 

i would stick with 235s. 235 40 or 235 45

 

I'm running 245/45 on an 18x7.5 wheel. I got way too much meat on the wheels. Go with 235/40.

 

It's been done before, but I wouldn't do it, so

 

stick with your current size.

btw, different tires from different companies have different specs depending on sidewall construction and stiffness - hence why some will fit that size and others say they won't.

 

im pretty sure it would be safe but juss like everybody else has said ud be better off stickin with the 235s... it's wide enough as it is...

 

I would NOT put that tire on a 7.5" rim. As the ratio increase (40 to 45) you get more leeway on the width of a rim you use. So you can use a 235 on a 7.5" rim in a 45 ratio, but shouldn't with a 40 ratio. Even more so with a wider 245mm tire. If you had a 50 ratio, you might be able to stick it on a 7.5" rim, but I wouldn't put a 40 on that rim. Safety and Specs aside, it wouldn't look good at all. You can put a 235/45+ or a 225 in any ratio on that 7.5" rim. You need an 8" rim for a 245/40. Keep in mind -wider tires are better traction, but lower gas mileage.

 

I just purchased some OEM 350Z Touring V.1 18's for the max. I was planning on getting some 225/45/18's for the front, and 245/45/18's for the back because of the offsets, should i instead get 235/45/18's for the back as you told turbobink?

 

What is the width of those rear rims? If it's 8 or 8.5" than either the 235 or 245 will probably fit. He was trying to install a 245/40/18 tire on a 7.5” wide rim -a wider tire, and smaller rim than your combination. FYI - a 225/45/18 is 26" diameter, a 235/45/18 is 26.5" diameter, and a 245/45/18 is 26.7" diameter. Your back wheel will be slightly larger than your front regardless.

 

dont do it. stick with 235/40-18.

 

I'm running 225/40R18.. 235 would be maximum I would go..

 

i currently run 235/40/18's i think its a good size n ride on the maxima!

Solo413

07 m35x
00 maxima

 

MY FRONT WHEELS R 18X8.5 +28 I GOT A 225/40/18