Tire sizes on stock wheels

[mordant80]

Alright, I can't seem to find a straight answer for this. The stock wheels are 18x7. I set of 225/45/18 will fit for sure but that would make the tire a lil taller than stock which I don't want. I would prefer 225/40/18 which would be closer to the stock tire height not to mention there is a MUCH greater selection of tires in this size. However one of the guys at tirerack was saying that the sidewalls would not be able to handle bumps and such with the weight of the car on the 225/40 size. So my question is.. is anyone running 225/40/18's on the stock rims and what are your experiences. Have there been any problems?

 

[Mid_Life_Crisis]

Alright, I can't seem to find a straight answer for this. The stock wheels are 18x7. I set of 225/45/18 will fit for sure but that would make the tire a lil taller than stock which I don't want. I would prefer 225/40/18 which would be closer to the stock tire height not to mention there is a MUCH greater selection of tires in this size. However one of the guys at tirerack was saying that the sidewalls would not be able to handle bumps and such with the weight of the car on the 225/40 size. So my question is.. is anyone running 225/40/18's on the stock rims and what are your experiences. Have there been any problems?

Depends on the particular tire. My winter tires are Kuhmo all seasons in 225/40/18 and they are fine on the stock rims.
My summer tires are Falken RT615 in 225/40/18 and the manufacturer calls for a minimum 7.5 inch rim. Check the manufacturer website for rim recommendations. Falken gives min, max, and recommended rim width for each tire they make. I believe the guys who designed the tires.

 

[mordant80]

Are you running those falkens on the stock wheels or did you get something wider for them? I was leaning towards those or maybe the kuhmo ecsta mx. From what I've seen most of the 225/40's call for a minimum of 7.5. Just hoping I can get away with it with no problems. On my last car I had 225/50/16's on a 6 inch rim that had 195's stock. Actually worked out quite well.