Minuet

I’m thinking of going with 265/40r18 on the rear but my rim is only 8.5” wide. All the charts say 9” minimum…

I’m not going to be taking it on a track. It’s just a daily driver.

What are the ramifications of going ahead with the 265/40r18 on a 8.5” rim?
Will it work?

TIA

Neo

iTrader: (3)

You are basically trying to put a 10.4" wide tire on a surface that is 8.5" wide. You make the call. 9" is the minimum that the manufacturer is recommending. Remember that is the mimimum. On top of that , if you want to keep OEM spec, you should really be running 265/35r18 tires.

It sounds like you are trying to run a staggered setup on non-staggered rims. People have been known to push the limits of specs and I am sure some one will tell you it will "work" since they've done it. It is all down to your personal level of acceptable risk. I personally would not do it. I would just wait to get staggered rims to do such a setup. In the meantime, just go 245 all around and you get to still be able to rotate tires.

rominl

iTrader: (4)

not a good idea at all. the rim is too narrow and the tire, when mounted, will have a lot of side force. when running hot, the tire could easily got "dismounted" from the rim by itself. dangerous imho

there is a reason for recommendation

rheiy

The 265/40/18 ranges in size from about 26.4 to 26.6 depending on tire brand.. Stock spec is 25.7.
even with 265/35/18 (closer to oem size) on 8.5 inch rims, the tire will have that donut look. You should really have 9's but 9.5 or 10 is ideal

SoCalSC4

Actually, an 8.5" wheel is actually 9.5" wide overall... 8.5" is the measurement from "bead seat to bead seat," and does not include the rim flange thickness.

A 265 on an 8.5" wheel is still 1" too wide and will look like butt.

Neo

iTrader: (3)

Good info. Thanks Bob.