Measuring tire circumference

Any hardware store would have it. Another way is pi r squared. So if your tire is 22.5 x pi ~~ 22.5x3.14= 70.65/12 = 5.88 feet around in circumference.

 

Probably be easier to use a piece of string or something similar and then measure it with a tape measure.

If you're not looking for the exact number, which will shrink as tires wear down, I'm sure google will easily find you the number you want based on tire size.

 

22.5 is the rim size, not the tire size. A LP22.5 is going to be roughly 40", an 11R22.5 or LP24.5 will be in the 42" neighborhood, and an 11R24.5 is going to be around 44" tall. Actual circumference will vary with tread patterns and wear, which is probably why he wants an actual measurement....more precise than doing the math based upon diameter...for better pairing of tires when rotating or possibly replacing one or more of them.

 

http://quartermax.com/retractable-tire-rollout-tape-measure/
There's also a tool made that looks like a sliding t-square where you hold it up to a tire and squeeze the tool into the treads and the gauge tells you your measurement. I'll try to find a pic

 

yep you're right, just measured my steer which was put on yesterday-- about 40 inches. roughly 10.5 feet around in circumference. Best way I agree would be to run a string around it then stretch the string out and measure the string.

 

Stagger stick
http://www.speedwaymotors.com/Stagger-Stick-65-to-115-Inches,2665.html
Might not be big enough for a truck tire tho...

 

I just used a regular tape measure to do mine when I had a set of tires shaved to be equal. I think it was a 10 foot tape, quarter inch wide.

 

Good gawd what's goin on in schools these days? I learned p r squared in 4th grade.

 

No insult meant at OP, btw.