255/70R18 vs 265/70R18
265/70R18 is taller than 255/70R18 by 1.72% — a diameter difference of 0.55″.
What changes between 255/70R18 and 265/70R18
Switching from 255/70R18 to 265/70R18 changes overall diameter by +1.72%, a taller tire by 0.55 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″ (255mm → 265mm), which affects contact patch and fender-well clearance. Sidewall height shifts by +0.27″: 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 66.1 mph. Both sizes share the same 18″ rim, so no wheel change is required — this is a pure tire-only swap.
| Spec | 255/70R18 | 265/70R18 |
|---|---|---|
| Overall diameter | 32.06″ | 32.61″ |
| Section width | 10.04″ (255 mm) | 10.43″ (265 mm) |
| Sidewall height | 7.03″ (70%) | 7.3″ (70%) |
| Rim diameter | 18″ | 18″ |
| Circumference | 100.7″ | 102.44″ |
| Revs per mile | 629 | 619 |
Interactive comparison
275/65R18 or "33" for inch aliases255/70R18
- Diameter
- 32.06″ / 814.2mm
- Section Width
- 10.04″
- Sidewall
- 7.03″ / 178.5mm
- Circumference
- 100.7″
- Revs/Mile
- 629
265/70R18
- Diameter
- 32.61″ / 828.2mm
- Section Width
- 10.43″
- Sidewall
- 7.3″ / 185.5mm
- Circumference
- 102.44″
- Revs/Mile
- 619
Speedometer & Diameter Impact
At an indicated 60 mph, your actual speed is 61.03 mph (98.22 km/h). Your speedometer reads 1.72% low versus actual speed.