Why do GPS speed and indicated speed disagree?
Speedometers assume a stock circumference. A different tire changes revolutions per mile and throws the gauge off.
ATV Calculator
ATV Tire Circumference Calculator
Convert a tire diameter or a width/aspect/rim size into circumference and how many times the tire turns each mile or kilometre.
Results
Values update after you calculate. Empty or invalid inputs will not invent a number.
Enter the values and choose Calculate to see estimates.
How it works
Enter an overall diameter, or enter width, aspect, and rim so diameter can be derived. Circumference is π times diameter. Revolutions per mile are 63,360 divided by circumference in inches.
Circumference = π × diameter. Revolutions per mile = 63,360 ÷ circumference (inches).
These results are estimates for planning only. They are not OEM specifications, safety certifications, or professional mechanical, legal, or financial advice.
Tire Circumference Calculator FAQs
Can I measure diameter on the ATV?
Measure from ground to the top of the tire and double-check that the machine is on level ground with normal pressure.
Are revolutions per km useful?
Yes if you are calibrating a metric speedometer or comparing imported tire data.
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