Tire size calibration
#1
JK Newbie
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Join Date: Jul 2010
Location: Calgary
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Tire size calibration
When calibrating for a new tire size. Do you input the tire manufacturers size ( unloaded) or do you input the measured tire size (loaded).
#2
JK Jedi
Originally Posted by mshahwan
When calibrating for a new tire size. Do you input the tire manufacturers size ( unloaded) or do you input the measured tire size (loaded).
#3
JK Jedi Master
Stick a piece of chalk in the tread.
Move the Jeep until there are two chalk marks on the pavement.
Measure the distance between the chalk marks.
Divide the measurement by 3.1416.
That's your tire diameter.
It removes the variables encountered with other methods.
#4
I was given this tip by H&S Performance. Measure from the ground to the center of the wheel. Multiply this by two and use it as your starting point. I got it right on the money first time when calibrating my Ram with it's 37's.
#7
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adjusting speedometer on a 2013 jksu
I just used AEV's Procal Module and the instructions that come with it say to measure. Never use the manufacturers dimensions. To the nearest quarter of an inch is as accurate as you need to be. Works great!
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#9
This seems like it could be inaccurate, the bottom half has load on it (the tire should have a little bulge) and the top half doesn't. I can't imagine it would be off all that far, but not the true diameter.
#10
JK Jedi Master
This is why the method in post #3 above is good. It removes such variables.