CALCULATOR · FREE免费 · Free
Tire Size Calculator
Enter tire width, aspect ratio and rim diameter to estimate sidewall height, overall diameter, circumference and revolutions per mile.
--Sidewall height · in
--Overall diameter · in
--Circumference · in
--Revs per mile · revs
Estimates only; verify on site before ordering or building.
Example
| Item | Value | Unit |
|---|---|---|
| Tire width | 225 | mm |
| Aspect ratio | 45 | % |
| Rim diameter | 17 | in |
| Sidewall height | 3.99 | in |
| Overall diameter | 24.97 | in |
| Circumference | 78.45 | in |
| Revs per mile | 807.6 | revs |
Where people go wrong
- Treating the aspect ratio as a sidewall measurement; it is a percentage of width.
- Confusing rim diameter with overall tire diameter.
- Changing size without checking speedometer error and fender clearance.
FAQ
What does 225/45R17 mean?
A 225 mm section width, a 45 percent aspect ratio and a 17 inch rim.
Why do revolutions per mile matter?
It affects the speedometer, odometer and shift logic; keep the difference under 3 percent when changing size.