I know that mazda3's can fit 17x7 wheels..
What's the widest wheel size that can fit our car?
Will 17x7.5 rims be ok or will it cause problems?

 

it should not but if you decide to lower your car be careful your tires might rub you wheel wells, but 17x7.5 is fine

 

Depends on the backspacing as well.

 

I've been told that a 7.5" rim with a 52.5mm backspace is optimal (I've had some disagree with me....)

My info is based on a fit study performed by a Mazdaspeed engineer checking to see which wheel sizes actually fit.

He also said that if you go with a rim that wide, you will probably need to roll the fender lips to avoid rubbing.

I fit a 225/45R17 on a 17x7....I really don't see you fitting a wider tire than that, so the wider wheel doesn't give you much (although the dish on the 7.5" wheels tends to be deeper, which looks cool.)

 

hey sslature. i was autocrossing two weekends ago with a man running 245mm width tires on 17'x7' wheels and said he had not rubbing issues at all. i was alittle perplexed by how he was managing to do so, and when i asked him about it he just said its based on the wheel offset. i failed to ask him, but what offset could his wheels have been? im running 215mm width tires on a 17'x7' wheel with a 40mm offset

 

My 225's rub on the front inner fenderwell, on the inside edge of the tire (about the 3 o'clock position) with a 60mm offset. (only at full lock).

I suppose you could run a 50mm offset and add 10mm to the inside and outside edges of the tire. I'd think you would need to roll the edges of the rear fender lips to clear them.

Most likely he does rub at full lock at the same spot as mine, but may not realize it. It would probably be easier to run those on a 7" wide rim rather than a 7.5" rim as it will keep the tire a little but thinner with the smaller rim.

I bet he hooks up and corners real nice....

 

on my 3 i got a set of 18 x 7.5 with a 225 40 18zr tire , and i got my ride lowered and i dont rub any where in the wells

 

Quite possible if you have the proper offset.

What offset are your wheels? (I would suspect somewhere in the 48-52mm range)

Try this, turn your steering wheel full lock left, do a complete 360 degree circle at full lock.

Take off your left front tire and see if you rub at what would be the 3 o'clock position if you are looking at the tire.

I thought I didn't rub for a while too, but I turned out to be wrong.

 

Would 215/50/17 tires be okay with the 17x7.5 rims? or should I go for a thinner wall, like a 45 wall?

 

that should be A-OK. im running the same tire size on my stock wheels. and on my aftermarket wheels i have a 45 wall. so either way you go, youll be fine.