225/75R15 vs 235/75R15
235/75R15 is a safe swap for 225/75R15 by the usual ±3% rule: the diameter differs by +2.09%.
Speedometer and odometer
With 235/75R15 on a car calibrated for 225/75R15, the speedometer reads 58.8 mph when you're really doing 60, and the odometer under-counts by 2.1%.
| Speedo shows | Actual speed |
|---|---|
| 30 mph | 30.6 mph |
| 45 mph | 45.9 mph |
| 60 mph | 61.3 mph |
| 70 mph | 71.5 mph |
| 80 mph | 81.7 mph |
Other sizes close to 225/75R15
Questions
Can I replace 225/75R15 with 235/75R15?
235/75R15 is a safe swap for 225/75R15 by the usual ±3% rule: the diameter differs by +2.09%.
What's the difference between 225/75R15 and 235/75R15?
235/75R15 is 0.59" taller and 10 mm wider; the sidewall is +0.30". At an indicated 60 mph you'd actually be doing 61.3 mph.
Will 235/75R15 fit on 225/75R15 wheels?
Both use a 15" rim, so the wheel diameter matches; check the wheel's width range for a 235 mm tire and the fender clearance.