would i notice any negative impact if i went from the factory 17" wheels on my 2005 sedan with 235/50/17 tires, to a set of factory 18" wheels off a coupe, with 225/45/18's in front and 245/45/18's in the rear? other than financial? someone is selling a set of rims/tires off their coupe and they have about 5200 miles on them. I thought it might be a cheap mod if it won't cause any problems with the ride/balance of the car.

also, do i have to have two different tire sizes? could i eventually replace them with all the same size? say the 245/45/18's. thanks.

I have a similar question only in reverse, I want to get a set of 17" for the winter and mount a set of snow tires on them. If you’re thinking of selling your 17" wheels I might be interested in purchasing them from you, depending how much shipping is. (Seriously)

well, as soon as i get an answer on the question i have, i will decide what i am going to do, and then i can let you know. my 17" rims are in mint condition and the tires have about 10k miles on them. they are michelin pilot xgt z4's tires.

The coupe tires are a little too short (smaller in diameter) than our sedan. Your speedo will read like a 1 to 2 mph higher than normal. But I've seen other people install them; with the drop, the coupe's rims are nice.

About the same size when you need to replace them, I think it is a bad idea since the front rims and the rear rims are difference width.

Anyone has technical reasons behind this?

Ah... the tires are a different size, but are the wheels a different width?

the coupe wheels have different offset - they won't fit on a sedan.