285/65R17 vs 255/75R17
255/75R17 is taller than 285/65R17 by 1.50% — a diameter difference of 0.47″.
What changes between 285/65R17 and 255/75R17
Switching from 285/65R17 to 255/75R17 changes overall diameter by +1.50%, 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 -1.18″ (285mm → 255mm), 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 -10, which translates directly to speedometer error — at an indicated 65 mph, actual speed becomes 66.0 mph. Both sizes share the same 17″ rim, so no wheel change is required — this is a pure tire-only swap.
| Spec | 285/65R17 | 255/75R17 |
|---|---|---|
| Overall diameter | 31.59″ | 32.06″ |
| Section width | 11.22″ (285 mm) | 10.04″ (255 mm) |
| Sidewall height | 7.29″ (65%) | 7.53″ (75%) |
| Rim diameter | 17″ | 17″ |
| Circumference | 99.23″ | 100.72″ |
| Revs per mile | 639 | 629 |
Interactive comparison
275/65R18 or "33" for inch aliases285/65R17
- Diameter
- 31.59″ / 802.3mm
- Section Width
- 11.22″
- Sidewall
- 7.29″ / 185.25mm
- Circumference
- 99.23″
- Revs/Mile
- 639
255/75R17
- Diameter
- 32.06″ / 814.3mm
- Section Width
- 10.04″
- Sidewall
- 7.53″ / 191.25mm
- Circumference
- 100.72″
- Revs/Mile
- 629
Speedometer & Diameter Impact
Narrower tire — verify wheel widthAt an indicated 60 mph, your actual speed is 60.9 mph (98 km/h). Your speedometer reads 1.50% low versus actual speed.