oghondaman

I'm gonna install 18x7.5 50mm offset wheels.I have a comptech drop.I've noticed most people use 225/40/18 tires.Why? Why not 225/45/18? Do 40's handle better?Ride quality?Looks? I'd appreciate comments.Thanks

EricL

You can use the 225/45-18 or 225/40-18.

Some of the 225/40-18s have low load ratings in the 225/40-18 size (it depends on make and model):

SO-3 has a load rating of 88 (that's pretty low and I'd hesitate to do that if I was carry a few people around at higher speeds).

http://www.tirerack.com/tires/Spec.j...+Pole+Position

Toyo T1-S has a load rating of 92 in the 225/40-18 (it has a reinforced casing).

(There are lots of different make and models of tires being run by members here. Depending on which one you select, your load rating might be fine or too low)


225/45-18 will have speedo reading about 2% too slow
225/40-18 will have speedo reading about 1.5% too fast

(I left out any discussion of the 235/40-18...)


OEM stock tire load rating is 93.

gsrblack

if speedo is reading 2% too slow vs. 1.5% too fast...which tire is wearing faster?

EricL

IMO, it’s not a significant factor.

The compound, construction differences, and a driving quirks would "bury" the minor differences. (I don't know too many people that buy performance tires and drive down a straight path forever...)

Nashua_Night_Hawk

You may be able to install 18x7.5 and 235/40/18... however u need to check the inner clearance... +48 would be ideal... and I have +45 and no problem...

EricL

+50 is even better...