[DragBean]

Yes aardvarcus. That is correct. I was originally thinking r13 meant an outside d of 26 but no.

The tires I'm replacing on the front drive train are 175/70r13 meaning fresh tires have an od of 22.5" if the math is 13+2×3.23×12×.60×175/1000
The tires are currently about 21.35 inches with load on them.

Does this mean mile odometer is counting miles short? Does the odometer compensate for changing tire sizes?

Also the current tread style seems pretty good (see pic) but the tires are only rated for 44 psi max. I'd have to get a similar tread and width to not negatively effect my mpg but if i get something with a higher psi rating and go a little bigger i should improve mpg a noticeable amount I'm thinking.

@fbov - so all the weight from the car gets transfer to the rims where the center bore contacts the axle? The lug bolts don't take the force?

Also there is the possibility of just using the dinged rim and getting new tires (it's not too bad, but I think it is probably permanently off balanced and may leak air) What do you think? The tread is so worn down that I'm losing almost an 1 & 1/4 from the new size (does that sound right?)

I think the max outside tire diameter I want to go with is 23" (compared to current 21 3/8")