2002 PT -> 17" rims -> speedo off?

[vk]

I know this has been somewhat answered in other questions, but there seems to be a lot of variables involved. I have a 2002 LE with the stock chrome wheels and was wondering if it was possible to go to a 17" rim and tire combo that wouldn't affect the speedometer or at least not affect it more than a few %. I know you can do the different sized rim and tire profile, so any ideas what would work (like would using the 2003+ GT rims give too much of a difference?)

[purple04]

The rims are not what affect the speedo, per se. The circumference of the tire is what is the final factor. Go to your tire store and they should have specs for tires that include revs per mile. Select a tire that is close or the same number of revolutions per mile to keep the speedo accurate.

[slartyblarfast]

The stock 17 inch tire size is 205 50 r17. You can go with a 235 45 and still be the same diameter. There are probably other sizes but these are the 2 that are closest. Go to Discount tire website and they have a tire size calculator that you can play with....

[Jimbo]

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

[Grouch]

The correct size for 17" wheels is 225/45/17 witch is what I have. There is less than a tenth of an inch difference from the stock 16". Your speedometer will only be off about 1 mph.

[1wedwudy]

I put 17" turbo wheels with stock badyears on mine and it didn't affect the speedo at all. I'm now running 215/55/17's and no problem.