I have an 07 "S" with factory 17" tires. My high performance summer tires are killing me in the Michigan snow and ice. I am looking for a set of tires and wheels for winter.

Can someone enlighten me as to the formula to determine what tires will fit what vehicle? Someone is selling a set of 2010 clubman 15" wheels....will they fit my car?

what factory tires/wheels are not compatible with what years and models of cars?....please help me understand!

Also other than adjusting for speedometer inaccuracies would there be any significant problem with going from a 17 to a 15 inch tire?

Also while we are on the subject....what is the point of a larger tire? I mean the "contact patch" on a 15 vs 17" tire is basically the same....isnt it?

 

Hi Vic,

15's will fit on your Clubman, you just need to make sure the bolt pattern of your current 17's is the same bolt pattern of the 15 inch rims you plan to obtain. Once you know that the bolt pattern is identical (not sure what it is for Clubman's, but for 02 to 06 Mini's, it's 4x100), you can then move to tires.

I have summer tires that are 17's, and my winters are 15's, so no, there is no significant problem going from one to another.

As far as the contact patch is concerned, that's based on the tire size itself. If you look at the 3 sets of numbers emblazoned on the side of your tire, they'll read something like 205/45/17. The first number is the width (or contact patch) of the tire, basically how much rubber meets the road. The second number is the height of the sidewall, or how much tire you can see from where the tire meets the pavement, to the outer edge of the rim. And the last number indicates the size rim the tire will fit.

A great site to help see what type of 15 inch tire will match your 17, go here: http://www.miata.net/garage/tirecalc.html

Enter in your stock tire size, and then play with the numbers on the 15 to have the circumference match your 17. As a general rule of thumb, for a winter tire, you'd normally go thinner than your summer tire. The less rubber moving through snow, the better your traction. The wider your tire, the more snow/slush the tire will push from beneath it. So if your summer tire is a 205, go with a 195 for a winter tire.

Take care,
-Dave

 

I would not try to go from 17s to 15s on an S, even if they cleared the calipers (which I'm not sure about). I think 16s would be a better fit for the S. Your factory 17s are 7" wide; factory 16s are 6.5" wide. Somewhat narrower tires than your current 17" size would probably work better in snow and slush. Try to choose a winter tire size that has a diameter and revolutions per mile that are about the same as the OEM tire size for your 17s. Otherwise, your speedometer and odometer might be even more inaccurate than they are now. My best advice, however, is to get advice from Tire Rack.

The factory 15" wheels are 5.5" wide, so they would take a narrower tire, with a higher aspect ratio (taller sidewall) to get to the same tire diameter that your 17s have. Theoretically, the narrow contact patch should work well in the snow. In dry weather, however, a wider/larger contact patch provides more grip. Bigger/wider wheels and tires weigh more (and it's unsprung rotating mass), however, so there is a point of diminishing returns in terms of performance.

 

Wider tires provide more lateral grip when cornering. Narrower tires provide more straight line grip when accelerating or braking.

 

Not sure I understand, do you have a 07 MCS Covertible (R52) if so, then yes most 15's should fit.

If you have 07 MCS Hardtop (R56) then no oem 15's will fit and very few aftermarket 15' wheels will fit. The R56 has the old R53 "JCW Brakes" which are bigger than oem R53 MCS.

+1

 

Thanks for all the replies.

I have an 07 S hatchback/hardtop

 

Looks baby - it's all about looks at the expense of ride comfort quality due to less side wall.