Do tires become shorter when mounted onto the wheel?
 

For instance... If you have a 28.0" tall brand new drag radial, and you get it mounted to the wheel, does it stretch it some (like stretching a rubber band) and make it say ~27.0-27.5" then? Or something like that? Or does it stay exactly 28.0" tall still? This with about 20-25psi in it once the wheel is in obviously.

Sorry if it's a dumb question! Thanks in advance. for the help.

Not a dumb question. If you look at the specs, you'll see the "rim width" spec for the tire, which tells you what the beads' width is for the unmounted tire. If you mount it on a wheel of that width, the diameter won't change at all. If you mount it on a wider or narrower tire, the diameter might change a teeny bit because the sidewalls are on a slightly different angle. However, I doubt it's more than 1/10".

Thank you for the quick response! I definitely appreciate it.

So, if I put a 9.5" in a tire the says 9" rim width it will make the tire a tiny bit shorter due to it stretching it somewhat?

And also at 20-25PSI not 30-35

There's a very small effect on diameter due to wheel width changes. I think for most tires the correlation runs something like this: an increase in the wheel width decreases the tire OD by 5% of the increase in wheel width.

IOW, mounting a given tire on a wheel 1" wider than the measuring width wheel for that tire could be expected to cause the tire OD to decrease by 0.05". On a 1" narrower than measuring width wheel, the tire OD would increase by about the same 0.05". Basically negligible.


Norm

Sorry I missed the follow-up question on 3/3, but I agree with Norm's answer.

Thank you both so much for helping a newbie like me out. I just wanted to check before making a tire purchase. Thanks again!