How the calculation works
Approximate clearance change = (new tire diameter − current tire diameter) ÷ 2. Estimated new clearance = current measured clearance + the change.
Worked example
Moving from 30-inch to 32-inch tires adds 2 inches of diameter and about 1 inch of theoretical clearance. With 12 inches entered as current clearance, the new estimate is 13 inches.
Measure the same reference point
Record the lowest relevant point on the machine on level ground with the same load, pressure, and suspension settings. Published clearance may use different conditions or a different point. Comparing your measured baseline is more useful than combining unrelated specifications.
Understand the half-diameter rule
The axle center rises by approximately the increase in tire radius. The simple half-diameter calculation assumes other geometry is unchanged. Independent suspension and changes in operating conditions can make the lowest part of the chassis behave differently. Check actual clearance after an approved installation.
Frequently asked questions
Does this include suspension lift?
No. The estimate includes only tire-diameter change. Suspension changes require a separate model-specific evaluation.
Will a taller tire rub?
This tool cannot answer that. Check full steering and suspension travel, offset, and approved wheel/tire combinations.
Can clearance decrease?
Yes. A smaller tire diameter produces a negative change. If the entries imply below-zero clearance, the tool asks you to verify them.