i have 4 245/45/18. right now i'm running 225/40/18 in front and 265/35/18 in rear and those fit fine. so will these fit?

 

You'll have better luck in the rims and tires section.

 

Depends on your offset...

245/45 is more for a 16" rim with a lowered car... which is what I am running with no problems.

My old setup was 18X9 and 18X10 running 225/35 and 285/30

I didn't have any clearance issues, but it was close.... running a 245 might cause the fenders to rub, and 45 is a bit thick also for 18's. I'd bet you're going to have some issues running those tires.

People stick with 17's because of the drivability factor. Driving on 18's is not too comfortable and it is prone to ruining the rims if you hit a large bump in the road...there are all kinds of posts in the tire section on offset and sizes. I do not see people running over 35 on most setups.

I wouldn't use that setup IMO.

 

i run the same rim size setup with 265s in the back +45 and 235s in the front +35 with no rubbing issues even in tight turning..

although i wouldnt recommend them if your roads are f'ed up, its basically for show..

 

I don't think the width is as much of a concern as the height of the tire... or the ratio rather. 45 is pretty large for 18's... I know people running 315 in the rear, no problems.. except they have a widebody. Anyway, 45 is large for an 18... I wouldn't recommend going over a 35 ratio.

 

The 245/45/18 will be roughly 20mm taller than the 225/40/18s, Its unlikely they will fit in the front.

 

The proper tire size is 245/35, NOT 245/45 18! Those will be a whopping TWO INCHES too tall!

 

You should check this out

http://www.miata.net/garage/tirecalc.html

it is a tyre size calcualtor.

The wheels you propose will give you speedo adjustment problems even if they do fit.

 

Doh Im an idiot. The sidewalls will be 20mm taller than the old tires, the diameter should be about 40mm taller. So yea, they wont fit.