Does anyone know if this tire fitment will work, you know it's less costly to chech than to buy and find out the hard way. On the front of my 2004 XKR: stock 245ZR40-19 and on the rear 275ZR35-19 Hankooks.

 

Did your 2004 XKR come with Atlas 19" rims ? as I'm looking to get a set for my 2001 XKR and wondered if they are a good fit.

 

My 2003 has 19 inch rims, too, and I put 285/30's on the rear. I left the front stock with 255/35's. Miata.net has a nifty little calculator which shows you how different tire sizes affect the the overall diameter of the tire. I assume you're trying to keep the diameter the same so it doesn't mess up the speedometer. My rims handled the wider tires with no problem. I probably could have even gone 20 or 30mm wider, the sidewall on the 285's barely protrudes past the edge of the rim. Another 20mm would only be about 7/16ths of an inch wider on each side of the rim. But if I had done that I would have had to use an even lower aspect ratio sidewall.

Here's the tire size calculator at miata.net:

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

 

simonnallan: Yes my car came with the wheels, they seem to fit fine.

 

Thanks Rev, I do want to keep the diameter the same because I would like to replace the rear springs with Miata springs so as to achieve less lean and more stability during cornering. it's good to talk to another FSM devotee.