Quick question: My 4 tires are almost due for a replacement on an '08 G35x on stock 17" wheels. There are no suspension mods and I plan to keep the stock wheels. The question is, can I go from the 225/55 17 to a 235/50 17, considering the difference in sidewall, radius and diameter are 1/3 of an inch?

Thanks

 

I dont see the problem in that. Wider is better.

 

Your speedometer will be off by about 1.8% according to the tire calculator:

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

 

A 245/50-17 would be nearly identical to stock diameter; just 0.4% deviation. That's less than the change in diameter your stock tires exhibit when their tread is worn down about half way.

 

wish i had considered going wider last month when i got tires!

 

Love that calculater

 

That's a good calculator. I used to use it.
I use this one now. This one lets you set OEM size manually or by choosing your vehicle, you can also enter more than one alternate tire size AND it will show you if a certain tire size exists or not.
http://www.1010tires.com/TireSizeCalculator.asp
it IS a Canadian site so there may be the odd variance.

 

Excellent! Seems like the difference between the 225mm and the 245mm tires is very minimal. I would assume they would fit on the stock 17" wheels? A 20mm difference hopefully shouldn't create any issues with rubbing and so on...

 

Actually, the width difference between 225mm and 245mm is a very noticeable 8/10 of an inch, but with the lower profile, 50 series vs. 55 series, the overall difference in diameter is indeed very minimal.

They will fit your stock 7.5" rim width just fine, and there shouldn't be any rubbing either.

 

FYI, my buddy with an 08 G35x just went with the 245's with the stock 17 inch tires, and while the tires fit without rubbing and are within the range of acceptable wheel width, there was quite a bit of tire bulge.

 

What brand and model of tire were they? I know that between makes and models, tire fitment does vary, but for that size, the normal rim width is spec'd at 7.5". so I don't know why it should have been bulged.

 

He went with the 245/50/17 Continental Extreme Contact DWS on the stock G35x rims. These tires have a minimum recommended wheel width of 7.5".
Next time I see him, I can take a pic for you guys.

 

Hmmm, from what I can see, Tirerack specs show a 6.5 to 8.5 range for recommended rim width, with a 7.5 measured rim width ( also known as "design rim width"; ie. the size it most naturally fits on), so I don't know where you got the info that 7.5 was a minimum.


http://www.tirerack.com/tires/tires....=yes&tab=Specs

 

Disregard my "minimum" comment. I was incorrect and was going off memory.

However, the 245/50/17's of that exact tire definitely have a signifigant tire buldge. I'll still work on a picture for you next time I see him.

 

Thanks for the feedback everyone. For now at least I'm getting a set of Firestone Winterforce snow tires to get me through the winter in 225/55 17. Afterwards I'll get a set of summer tires in 245 width.