I know this may be a dumb question I read somewhere that when you upgrade your wheels/tires you do something called plus sizing to keep the numbers proportional. Can someone please explain this to me and how would I plus size my R 195/55-15 to 16" or 17" wheels? Thanks in advance for any help.


[Modified by ITRyder, 4:41 AM 7/10/2001]

 

Plus sizing is when you increase the diameter of the wheel and but keeping the same rolling diameter of the orginal.

195-55-15
215-45-16
205-40-17
215-35-18

Is the typical sizes too keep stock rolling diameter. Truthfully dont do 17's, go with a set of 16's if you do upgrade.

 

Boba is correct.

To clarify a liitle.

The first number you see is the durability of the tire (I believe).
195 is softer than 215

The second number is the width of the sidewall.
The lower the number, the less sidewall (or lower profile).

The last number is obviously the size of the inner diameter that the tire is covering or the simply put...the size of the wheel the tire has to cover.

You may have already known all of this, but I thought I'd offer it in case you were unclear.

If you've been readin the posts on this board for a while, you'll know that the general consensus is that 16" is the max size wheel for the ITR in regards to performance. IMO, rightfully so.

 

__________________________________________________ _
The first number you see is the durability of the tire (I believe).
195 is softer than 215
__________________________________________________ _

Actually, the first number is the width of the tire in millimeters.

Here's a link for tire sizing info...
http://www.tirerack.com/tires/tiretech/size.htm

Here's a link from tirerack that explains plus sizing...
http://www.tirerack.com/wheels/tech/plusone.htm


[Modified by CPR, 10:43 AM 7/10/2001]

 

So 215-45-16 is the correct size when upgrading to a 16" wheel. Would it not be wise to go with 205 instead? It seems it is so much easier to get tires in 205/16/45 than 215.

 

This makes Life easy
http://www.miata.net/garage/tirecalc.html

 

215/45 is the correct size if you go to 16's. But money wise its better to go with the 205's.

The problem I see with going to 16's are the tire choices. They seem more limited than the 15's and 17's. I'm still looking for a good autox/street tire in 215/45/16's.. I'll probably try Michelin Pilot Sport 215/45/16's next..

Err. Correction.. I'll probably try the Falken Azenis 215/45/16's next.. Much cheaper and suppodly a good autox tire too.


[Modified by arren123, 10:12 AM 7/10/2001]