I've got Evo 5's that I was previously running 235/40/18's on. The rims are 18X8 and I need new rubber this year as I picked up two nails late last year. Question is I am trying to find some used rubber to take me through this season and I have come across some 225/45/18 Potenza RE040 tires really cheap. Does this narrow of a tire look stupid on these rims (anybody have pics?) would I be more prone to bends using these tires?

 

I'd stick with 235 or go w/245's

 

that combination will give you a strange sized sidewall for 18s. 45 series sidewall on a 225 is gonna look weird, same with 235 or 245. the wider the tire, the more sidewall you will have. you can run those, it wont cause a problem, but its not gonna be the best looking tire, which a 235 or 245/40 would be.

 

Actually a 45 series tire would give you slightly more sidewall and help cushion the wheel a little more when you hit a pothole. As for 225 vs 235, the real determining factor in how a wheel looks is the width of the actual rim, as in 18X7.5 will look thinner than 18 X 8 which will look thinner than 18 X 8.5 - I have found over the years that going up 1 size (as in going from 225 to 235) will not have such a significant visual effect. Now you will notice the difference between 225 and 245 on the same wheel. I don't think a 45 series tire would look weird at all as I've seen plenty of pics of cars with them and they look just fine. 40 series is just a thinner sidewall which would probably look a little better. JMO

 

Would Buying a tire with a higher maximum PSI and inflating to 45psi or higher on a 235/40/18 have the same beneficial effects as going to a slightly larger sidewall. (comparing 235/40/18 to 235/45/18)