Why is my speedometer off after changing tire size?
A speedometer that reads inaccurately after a tire size change is caused by the difference in circumference between your new and factory tires. The bigger the size difference, the more noticeable the inaccuracy. A tuner, programmer, or shop recalibration can quickly correct the issue.
If your ATV or UTV has a digital speedometer, changing to a significantly different tire diameter can cause it to read inaccurately. The speedometer calculates speed based on how many wheel rotations happen per unit of time -- and that changes when tire diameter changes.
How big of a difference matters: Minor size changes (staying close to stock diameter) typically have a minimal effect. Going much larger -- for example, jumping from 26' tires to 30' tires -- can cause a more noticeable discrepancy.
What to do about it: Many modern UTVs and ATVs have a speedometer recalibration option in the settings menu. Some require a programmer or dealer recalibration. Check your machine's owner's manual or consult your dealer for the specific recalibration process for your make and model.
Have questions about tire size changes for your ATV or UTV? Contact our team and we can walk you through the implications before you buy.