245/65R17 vs 255/65R17
255/65R17 is taller than 245/65R17 by 1.73% — a diameter difference of 0.51″.
What changes between 245/65R17 and 255/65R17
Switching from 245/65R17 to 255/65R17 changes overall diameter by +1.73%, a taller tire by 0.51 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″ (245mm → 255mm), which affects contact patch and fender-well clearance. Sidewall height shifts by +0.26″: a taller sidewall softens ride quality and adds off-road bump protection, with some loss of steering crispness. Revs per mile moves by -12, which translates directly to speedometer error — at an indicated 65 mph, actual speed becomes 66.1 mph. Both sizes share the same 17″ rim, so no wheel change is required — this is a pure tire-only swap.
| Spec | 245/65R17 | 255/65R17 |
|---|---|---|
| Overall diameter | 29.54″ | 30.05″ |
| Section width | 9.65″ (245 mm) | 10.04″ (255 mm) |
| Sidewall height | 6.27″ (65%) | 6.53″ (65%) |
| Rim diameter | 17″ | 17″ |
| Circumference | 92.8″ | 94.41″ |
| Revs per mile | 683 | 671 |
Interactive comparison
275/65R18 or "33" for inch aliases245/65R17
- Diameter
- 29.54″ / 750.3mm
- Section Width
- 9.65″
- Sidewall
- 6.27″ / 159.25mm
- Circumference
- 92.8″
- Revs/Mile
- 683
255/65R17
- Diameter
- 30.05″ / 763.3mm
- Section Width
- 10.04″
- Sidewall
- 6.53″ / 165.75mm
- Circumference
- 94.41″
- Revs/Mile
- 671
Speedometer & Diameter Impact
At an indicated 60 mph, your actual speed is 61.04 mph (98.23 km/h). Your speedometer reads 1.73% low versus actual speed.