EthensCobalt

I want to get a thread with the most info about the best tire fitment and best performance with the tire, the brand is not needed just the tire sizes here folks.
What is the widest tire that can be put on the stock 18s
Whats the biggest sidewall ?
stock is 215/45/18
what about 225/40/18? will this even fit ? or can we go bigger to like 235

2fastforyouraSS

thats a good size i have my stock ones on the back and two 215/40R/18s on the front they work great i would recommend them or like u said the 225's

Cobalt Mav

I have 225/45, but I've talked to someone who fit 235/40 with no problems

EthensCobalt

ok im havin an argument with my brother about the tire sizes and what they mean he works at a autocenter
he says that the 215 is the tire height the 45 is the width however a 40 is larger width right

stealththx

215 is the width and 45 is the sidewall height. It is a little more complicated than that but that is the basic explanation. I run 225/40s and it handles/looks excellent.

2K5SS/SC?

215 is the width and the 45 is the aspect ratio (i.e. sidewall thickness). The lower the aspect ratio, the thinner the sidewall thickness is.

edit- damn you beat me to it stealththx!

EthensCobalt

thats what i thought ........ sams teaches him the other way around