I had 225/40/18 tires and the car drove like crap in comparison with the stock wheels which are back on the car 225/50/17. Yes, the tires were balanced but I never got an alignment. I believe it had something to do with the tire size. Luckily the tires had a defect and I’m getting new tires. However, I can’t decide between 245/40/18 or 235/45/18. Does anyone have a suggestion that is knowledgeable in this area as to which choice would be best for 18 by 8 wheels? I have the rims for sale in the sales thread, but I might keep them since no one has offered to buy them.
Thanks

 

You need to try to stay close to the OEM size for best results IMHO

check this site to find the right size

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

 

I have 225/40 18, which are the recommended size. But I like the OEM 235/45 17 better as well. But I think 45 series in 18 will slightly affect the speedo readings.

Which is why I'm going to go with the G35 17's on 235/45 17..... I should have dropped first though. I hate the gap.

 

To my knowledge OEM is 225/50/17. And the smaller the diameter difference the better, which would mean that 245/40/18 is best.

 

Stock on my 2002 GLE is 215/55/17 and I believe it is the same on the SE as well. There aren't too many tires made in this size so many of us are running 225/50/17 as it is a comparable size to stock.

 

standard size on the 2002 SE is 225/50/17. Mine came this way.

As for the 18" tire question, the best tire to run is a 235/40 if your wheel is 8" wide. with 8.5" wide wheels, you can run a 245/40 or a 235/40.

 

What brand of tires do you have?