Specific calculators, planners, and explainers for jobs that usually get buried in forums.
HTML-first, no account wall
Shareable URLs and direct outputs
Motorcycle tyre size comparison tool
Compare a current front and rear tyre pair against a proposed swap, then see what changes in sidewall height, overall diameter, circumference, ride height, effective gearing, and tire-only speed difference. It is built for modern metric motorcycle tire or tyre sizes such as 120/70ZR17 and 180/55ZR17.
What riders usually need to know
Size changes are rarely just about whether the tyre physically fits on the rim. A taller front can calm steering and lift the nose. A taller rear can raise the tail, lengthen rollout, and make gearing effectively taller. A much wider tyre can also create shape and clearance issues even if the simple diameter math looks acceptable.
That is why this page compares the whole pair and translates the result into fitment-style notes rather than only listing raw dimensions.
Useful for
- Comparing stock and replacement sizes before ordering a different tyre profile
- Estimating how a supermoto, ADV, or sport-touring wheel and tyre swap changes ride height and rollout
- Getting a quick tire-only sense of gearing and speed-reading drift before deeper fitment checks
Important limits
This is geometry only. It does not know your rim-width approvals, carcass shape, swingarm or fork clearance, chain run, mudguard clearance, ABS calibration, or manufacturer recommendations. Treat it as a planning tool, then confirm fitment with the bike and tyre maker.