305/45R22 vs 33x12.50R22
33x12.50R22 is a safe swap for 305/45R22 by the usual ±3% rule: the diameter differs by +0.59%.
Side by side
| 305/45R22 | 33x12.50R22 | Difference | |
|---|---|---|---|
| Overall diameter | 32.81" | 33.00" | +0.19" (+0.59%) |
| Section width | 305 mm | 318 mm | +13 mm |
| Sidewall | 5.40" | 5.50" | +0.10" |
| Rim | 22" | 22" | same |
| Circumference | 103.1" | 103.7" | +0.6" |
| Revs per mile | 615 | 611 | -4 |
| Ride height | — | — | +0.10" |
| Speedometer reads 60 mph | 60.0 | 60.4 | +0.4 mph |
Speedometer and odometer
With 33x12.50R22 on a car calibrated for 305/45R22, the speedometer reads 59.6 mph when you're really doing 60, and the odometer under-counts by 0.6%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.2 mph |
| 45 mph | 45.3 mph |
| 60 mph | 60.4 mph |
| 70 mph | 70.4 mph |
| 80 mph | 80.5 mph |
Other sizes close to 305/45R22
Questions
Can I replace 305/45R22 with 33x12.50R22?
33x12.50R22 is a safe swap for 305/45R22 by the usual ±3% rule: the diameter differs by +0.59%.
What's the difference between 305/45R22 and 33x12.50R22?
33x12.50R22 is 0.19" taller and 13 mm wider; the sidewall is +0.10". At an indicated 60 mph you'd actually be doing 60.4 mph.
Will 33x12.50R22 fit on 305/45R22 wheels?
Both use a 22" rim, so the wheel diameter matches; check the wheel's width range for a 318 mm tire and the fender clearance.