I have the sedan lx and I am putting on 17x7s and it said that the tire size to go with 205-45-17, but I thought the transmision in our cars were the same! So if I go with the 17s like the MSP shouldn't I run the same size tire? I personally would like a wider tire (205-45-17) but dam they get pricy. And isn't going to the 215s gona make my speedo off! SO, has anyone done this and what do ya think?
Thanks
Bryan

 

Go to: www.miata.net/garage/tirecalc.html

The OEM wheel/tire size is 195/55-15 on the LX. It looks like your best match in terms of minimal speedo error would be: 205/40-17.

 

Definitely get the 40 series. The 215/45-17 the MP3/MSP uses is nearly an inch taller than your OEM tire, which is like gearing your final drive much taller (=slower!). The 205/40-17 is nearly a dead-even match for your 195/55-15's in overall diameter. Even so, expect a much harsher ride over small pavement inperfections, and a little bit slower acceleration with the larger wheels due to rotating mass, regardless of your tire size choice.