Hey need some input. I have a line a smoking deal on a set Michelin Pilot Sport PS2. The question I have is I am running 235 50 18's and the Michelins are 235 40 18's. How much of a difference will the side wall height be on the Michelins compared to current tires? Thanks for the help.

 

This is just one of a million tire size calculators available online.

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

 

I wouldn't do it by the way. That's almost 2 inches less in diameter. Your car will be 1 inch lower to the ground and your wheel well gap will be 1 inch more. It will look like crap unless you lower it and remember you are allready 1 inch closer to the ground.

 

The 40's won't have the rated load capacity of the 50's either - they are a much smaller tire in that respect also. You'd be significantly underinflated relative to what the 40's would need if you inflated them at or even somewhat above the sticker pressures on your car. And the TPMS would never pick it up unless the tire tech knows what pressures they would need and recalibrates the system accordingly. I'm not holding my breath on that one.

Don't do it.


Norm

 

dont do it