255/65R18 vs 265/65R18
265/65R18 is taller than 255/65R18 by 1.65% — a diameter difference of 0.51″.
What changes between 255/65R18 and 265/65R18
Switching from 255/65R18 to 265/65R18 changes overall diameter by +1.65%, 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″ (255mm → 265mm), which affects contact patch and fender-well clearance. Sidewall height shifts by +0.25″: 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 | 255/65R18 | 265/65R18 |
|---|---|---|
| Overall diameter | 31.05″ | 31.56″ |
| Section width | 10.04″ (255 mm) | 10.43″ (265 mm) |
| Sidewall height | 6.53″ (65%) | 6.78″ (65%) |
| Rim diameter | 18″ | 18″ |
| Circumference | 97.55″ | 99.16″ |
| Revs per mile | 650 | 639 |
Interactive comparison
275/65R18 or "33" for inch aliases255/65R18
- Diameter
- 31.05″ / 788.7mm
- Section Width
- 10.04″
- Sidewall
- 6.53″ / 165.75mm
- Circumference
- 97.55″
- Revs/Mile
- 650
265/65R18
- Diameter
- 31.56″ / 801.7mm
- Section Width
- 10.43″
- Sidewall
- 6.78″ / 172.25mm
- Circumference
- 99.16″
- Revs/Mile
- 639
Speedometer & Diameter Impact
At an indicated 60 mph, your actual speed is 60.99 mph (98.15 km/h). Your speedometer reads 1.65% low versus actual speed.