Tire dimensions
 

Hey guys, need to get new tires for the Mazda3. right now it has P205/50R17 . sadly not many tires are made in that size, any ideas what i can do, could i change from a 50 to a 55 or 45 without any problems?

RE: Tire dimensions
 

You could run a 215/45R17 just fine on your stock rim. If you had a 7" wide rim you could go with a 225/45R17 (That's what I'm running now.)

A 225 will fit on your 6.5" wide rim, but it may crown a little and I know they aren't recommended for a wheel less than 7"

RE: Tire dimensions
 

so the tire is a little wider and about the same height right? if i go with the 215/45R17 will i have to get the speedometer recalibrated, i heard somewhere you have to do that when you change tire sizes.

i measured and it looks like i have a 7" rim, not sure if thats right or not, its the stock rim.

RE: Tire dimensions
 

If it's the stock Mazda3 wheel then you've got a 17x6.5", I'm running Mazda6 wheels which are 17x7"

You can run the 215/45R17 with no problem. No need to get the speedo calibrated as it's only a difference of 1.8%

Go to this link and play with the numbers a little and you'll understand it better. If you're speedo was reading 70mph, you'd actually be going ~68.75mph...i.e. not enough to worry about

http://www.discounttire.com/dtcs/infoTireMath.dos

RE: Tire dimensions
 

how can you change the width of the tire from a 205 to 215 and still have it fit on a 6.5" rim?

RE: Tire dimensions
 

Tires can be mounted on a variety of different wheel sizes. Some just work better than others.

The difference from a 205 to a 215 is 10mm, less than 0.5", so no problem, if you bump up to a 225 (20mm wider than stock) the tire can tend to crown (think like the shape of a motorcycle tire). Each tire manufacturer recommends specific wheel widths for their tires, but they tend to specify a range not a specific value(6-6.5" wide, 6.5-7" wide, etc.)