How the calculation works
Equivalent effective reduction ratio = baseline reduction × stock tire diameter ÷ new tire diameter. Reduction change = (stock diameter ÷ new diameter − 1) × 100. Travel-per-revolution change = (new diameter ÷ stock diameter − 1) × 100.
Worked example
With a baseline 10:1 reduction and a change from 30-inch to 32-inch tires, the equivalent ratio is 9.375:1, a 6.25% reduction in mechanical advantage at the ground. Travel per wheel revolution increases 6.67%.
Taller gearing versus lower gearing
A larger tire makes effective gearing taller: more distance per wheel revolution and less ideal tractive force for the same axle torque. A smaller tire makes it lower: less travel per revolution and more ideal mechanical advantage. These are geometric comparisons, not guaranteed acceleration or top-speed results.
Choose a comparable baseline
Use the same gear and operating basis for each comparison. If you do not know the overall reduction, leave the illustrative 10:1 value to understand the percentage change; do not describe it as your machine’s ratio. Actual CVT ratios can vary continuously, so a single overall number may not represent an entire ride.
Frequently asked questions
Does a 6.67% taller tire mean 6.67% less torque?
No. Travel increases by the diameter ratio, while equivalent ground-force multiplication changes by its reciprocal. The percentage changes have different denominators.
Will top speed increase?
Not necessarily. Available power, gearing, speed limiting, terrain, and CVT behavior can prevent a theoretical speed gain.
Can this choose clutch parts?
No. Use model-specific manufacturer guidance or qualified service support for clutch and drivetrain changes.
Reading this estimate
The mechanical gears stay unchanged. Equivalent reduction multiplies your baseline ratio by old tire diameter divided by new diameter. A smaller equivalent number is taller effective gearing; the tool is not a clutch tune or an acceleration prediction.
Why do diameter and reduction percentages differ?
They use inverse ratios. For 30 to 32 inches, travel grows 6.67% while equivalent reduction drops 6.25%. Label which percentage you are discussing.
Supporting explanation reviewed October 8, 2026.