minus sizing

Fiqure the diameter of what you are rolling on now:

Or just measure it.

For the new tire on 13" rim:

For the new tire on 14" rim:

I may help us to know what vehicle you're going to try this on, for example, will a 13 or 14 inch wheel fit over the brake caliper??

SteveL

Now I'm thinking 195/70/14 might be a better choice.

Well, I had posted a reply to this via Google but it didn't take for some reason so I'm trying again...

This is purely theoretical/hypothetical but the target vehicle would be a 2008 Scion xB. In theory I would put some kind of 14" rim with

Or you could just use someone's online tire size calculator.

There is one here:

Punching in

We get:

Specification Sidewall Radius Diameter Circumference Revolutions Speedometer Odometer Difference

Very close, good job! :)

Thanks for the link. That's a good calculator. I used this one also:

The thing is, 215/65/14 doesn't appear to be a real tire size. I don't see any listed in that size on tirerack.com or other sites. And besides, when you decrease sidewall, you usually increase width slightly, and conversely I would think that when minus sizing one would decrease width slightly, hence the 195 width as opposed to the

If you want to see how the right height, speedometer readings, etc, change this site is easy to use for that..

Keep in mind the smaller wheels may not clear the brakes.

That's a nice one too. But I like how the powerdog one gives you the sidewall result also.

Yes, this was mentioned earlier. Good point!