235/60R18 vs 245/60R18
245/60R18 is taller than 235/60R18 by 1.62% — a diameter difference of 0.47″.
What changes between 235/60R18 and 245/60R18
Switching from 235/60R18 to 245/60R18 changes overall diameter by +1.62%, 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 -11, which translates directly to speedometer error — at an indicated 65 mph, actual speed becomes 66.1 mph. Both sizes share the same 18″ rim, so no wheel change is required — this is a pure tire-only swap.
| Spec | 235/60R18 | 245/60R18 |
|---|---|---|
| Overall diameter | 29.1″ | 29.57″ |
| Section width | 9.25″ (235 mm) | 9.65″ (245 mm) |
| Sidewall height | 5.55″ (60%) | 5.79″ (60%) |
| Rim diameter | 18″ | 18″ |
| Circumference | 91.43″ | 92.91″ |
| Revs per mile | 693 | 682 |
Interactive comparison
275/65R18 or "33" for inch aliases235/60R18
- Diameter
- 29.1″ / 739.2mm
- Section Width
- 9.25″
- Sidewall
- 5.55″ / 141mm
- Circumference
- 91.43″
- Revs/Mile
- 693
245/60R18
- Diameter
- 29.57″ / 751.2mm
- Section Width
- 9.65″
- Sidewall
- 5.79″ / 147mm
- Circumference
- 92.91″
- Revs/Mile
- 682
Speedometer & Diameter Impact
At an indicated 60 mph, your actual speed is 60.97 mph (98.13 km/h). Your speedometer reads 1.62% low versus actual speed.