235/60R20 vs 245/60R20
245/60R20 is taller than 235/60R20 by 1.52% — a diameter difference of 0.47″.
What changes between 235/60R20 and 245/60R20
Switching from 235/60R20 to 245/60R20 changes overall diameter by +1.52%, a taller tire by 0.47 inches. This lands inside the ±3% fitment safe zone, so most vehicles will accept the swap without rubbing, speedometer recalibration, or ABS/TPMS complications. Section width moves by +0.40″ (235mm → 245mm), which affects contact patch and fender-well clearance. Sidewall height shifts by +0.24″: a taller sidewall softens ride quality and adds off-road bump protection, with some loss of steering crispness. Revs per mile moves by -9, which translates directly to speedometer error — at an indicated 65 mph, actual speed becomes 66.0 mph. Both sizes share the same 20″ rim, so no wheel change is required — this is a pure tire-only swap.
| Spec | 235/60R20 | 245/60R20 |
|---|---|---|
| Overall diameter | 31.1″ | 31.57″ |
| Section width | 9.25″ (235 mm) | 9.65″ (245 mm) |
| Sidewall height | 5.55″ (60%) | 5.79″ (60%) |
| Rim diameter | 20″ | 20″ |
| Circumference | 97.71″ | 99.2″ |
| Revs per mile | 648 | 639 |
Interactive comparison
275/65R18 or "33" for inch aliases235/60R20
- Diameter
- 31.1″ / 790mm
- Section Width
- 9.25″
- Sidewall
- 5.55″ / 141mm
- Circumference
- 97.71″
- Revs/Mile
- 648
245/60R20
- Diameter
- 31.57″ / 802mm
- Section Width
- 9.65″
- Sidewall
- 5.79″ / 147mm
- Circumference
- 99.2″
- Revs/Mile
- 639
Speedometer & Diameter Impact
At an indicated 60 mph, your actual speed is 60.91 mph (98.03 km/h). Your speedometer reads 1.52% low versus actual speed.