How it works
A taller tire travels farther per turn. Equivalent ground-force multiplication changes by stock diameter divided by new diameter. The loss is one minus that ratio. To restore the same ideal gearing, increase mechanical reduction by new diameter divided by stock diameter. Weight and riding style are context for the supplier; they do not reveal engine torque, tire mass or clutch calibration.
Worked example
Changing from 30 to 35 inches lowers equivalent gearing by 14.29%. Restoring the original ratio needs a 16.67% ratio increase, equivalent to a 14.29% output-speed reduction. These describe the same target in different conventions. A marketed “15% reduction” must be checked against its manufacturer’s definition.
What this tool cannot recommend
No universal reduction range or “stock clutching OK” verdict can be calculated from these four inputs. A kit maker needs the exact year, engine, transmission, tire construction, installed modifications and use. A Honda DCT or Yamaha sequential transmission also differs from a belt CVT. The result is a question to take to the supplier, not an approval or installation prescription.
SuperATV’s model-specific reduction application guidance illustrates why available ratios and fitment must be checked for the actual machine. No affiliate recommendation is made by this calculation.
Frequently asked questions
Does a clutch kit change the fixed mechanical gear ratio?
A CVT calibration can change how the system shifts and operates; it does not itself establish a different fixed gearbox ratio. Check the product’s exact function.
Why are 14.29% and 16.67% both shown?
They use inverse definitions. A 35/30 ratio multiplier is 1.1667, while 30/35 output speed is 0.8571. Confirm how a supplier describes its reduction.
Does entering weight let the tool approve a clutch?
No. Weight is recorded as application context. Torque curve, tire mass, transmission design and manufacturer-specific guidance are still required.
Can I use the same kit advice for every UTV?
No. Exact year, trim and transmission matter. The planner deliberately does not label a kit necessary or stock calibration approved without that evidence.