a 235-45-17 will be approximately 25.33 inches tall or a circumference of 79.6 inches, versus a 235-50-17 at 26.252" or a circumference of 82.4.

What are the measurements of the stock 215/55/17 tire?

approximately 26.311. (82.65). These sizes are based on theoretical values and actual sizes will vary by manufacturer.

So they are both a bit smaller than the stock tire and each wider. The advantages of the wider tire would be better handling and traction... correct.

Ronnie--
Yes, you are correct. An additional advantage of a smaller sidewall (what has been recommended so far) is lower sidewall flex, and therefore better handling. Front tires will last a bit longer too, or at least wear evenly, since they won't have the tendency to roll over onto the sidewall under hard cornering.

Not with Z springs

That being said, would the 45 or 50 series tire be better?

Go with the 45s. Then, in due time, if you think the wheel gap is too large we can drop you with a set of Eibachs (P/N 6363.140). One of the cheapest first mods you can do (around $200 with a DIY install). Call me up if you have any questions.
Cheers,
SK

I'll touch base with you before I buy the tires.
Thanks for the help.

I would suggest using a calculator to get the proper fitment. My '00 TL came from the factory with 205/60R16 tires. I wanted a bit more meat, so I used this website's chart:
http://www.tirereview.com/?type=cc&i...3c73d=179#plus

to come up with my meatier 215/55R16s and I was super happy. Not a squeak outta those tires the entire time, and they stuck!

you will definitely have to drop it a bit if you go with 235-45-17 .... personally i prefer 225-50-17 whcih is a better compromise if you want a smaller sidewall then the OEM 215-55-17..... and want to remain on OE suspension.

I just ordered the Kumho Ecsta SPT 225/50/17 tires all around for my 05. Should be a good upgrade over the stock Goodyears.

i got 235/45/r17's all around and im on s-techs so far no ribbing issues what so ever. Very happy with the overall look =o)

Unbelievable! 42 replies and not a single Tire Size Calculator link... http://www.miata.net/garage/tirecalc.html. C'mon guys... technology is your friend!

Enter the stock size 215/55/17 and the alternative size you're comparing, and the tool will tell you how much taller/shorter, wider/narrower, etc. and also how much your speedo will be off.

Have fun!

Keep the diameter & width close to stock.

You never want to significantly change the diameter no matter what.

Width depends on rim.

.