275/60R20 vs 285/60R20
285/60R20 is taller than 275/60R20 by 1.43% — a diameter difference of 0.47″.
What changes between 275/60R20 and 285/60R20
Switching from 275/60R20 to 285/60R20 changes overall diameter by +1.43%, 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 +0.39″ (275mm → 285mm), which affects contact patch and fender-well clearance. Sidewall height shifts by +0.23″: a taller sidewall softens ride quality and adds off-road bump protection, with some loss of steering crispness. Revs per mile moves by -8, which translates directly to speedometer error — at an indicated 65 mph, actual speed becomes 65.9 mph. Both sizes share the same 20″ rim, so no wheel change is required — this is a pure tire-only swap.
| Spec | 275/60R20 | 285/60R20 |
|---|---|---|
| Overall diameter | 32.99″ | 33.46″ |
| Section width | 10.83″ (275 mm) | 11.22″ (285 mm) |
| Sidewall height | 6.5″ (60%) | 6.73″ (60%) |
| Rim diameter | 20″ | 20″ |
| Circumference | 103.65″ | 105.13″ |
| Revs per mile | 611 | 603 |
Interactive comparison
275/65R18 or "33" for inch aliases275/60R20
- Diameter
- 32.99″ / 838mm
- Section Width
- 10.83″
- Sidewall
- 6.5″ / 165mm
- Circumference
- 103.65″
- Revs/Mile
- 611
285/60R20
- Diameter
- 33.46″ / 850mm
- Section Width
- 11.22″
- Sidewall
- 6.73″ / 171mm
- Circumference
- 105.13″
- Revs/Mile
- 603
Speedometer & Diameter Impact
At an indicated 60 mph, your actual speed is 60.86 mph (97.94 km/h). Your speedometer reads 1.43% low versus actual speed.