265/65R18 vs 275/65R18
275/65R18 is 0.51 in (13.0 mm) taller than 265/65R18 (+1.62%). Ground clearance at the axle changes by about +0.26 in. At an indicated 60 mph you would really be going 61.0 mph.
Side by side
Solid blue = 265/65R18, dashed orange = 275/65R18. Drawn to scale.
| Measurement | A265/65R18 | B275/65R18 | Change |
|---|---|---|---|
| Overall diameter | 31.56 in801.7 mm | 32.07 in814.7 mm | +0.51 in+13.0 mm+1.62% |
| Section width | 10.43 in265.0 mm | 10.83 in275.0 mm | +0.39 in+10.0 mm+3.77% |
| Sidewall height | 6.78 in172.3 mm | 7.04 in178.8 mm | +0.26 in+6.5 mm+3.77% |
| Circumference | 99.16 in2518.6 mm | 100.77 in2559.5 mm | +1.61 in+40.8 mm+1.62% |
| Aspect ratio | 65.0% | 65.0% | 0.0 pts |
| Revolutions per mile | 639.0 | 628.8 | -10.2-1.60% |
Open this comparison in the calculator to change either size.
Speedometer error
| Speedometer shows | Actual speed | Change |
|---|---|---|
| 20 mph | 20.3 mph | +0.3 mph |
| 30 mph | 30.5 mph | +0.5 mph |
| 40 mph | 40.6 mph | +0.6 mph |
| 50 mph | 50.8 mph | +0.8 mph |
| 60 mph | 61.0 mph | +1.0 mph |
| 70 mph | 71.1 mph | +1.1 mph |
| 80 mph | 81.3 mph | +1.3 mph |
What changes
275/65R18 is 0.39 in (10.0 mm) wider, and its sidewall is 0.26 in taller. Both mount on a 18 in wheel.
Each mile, 265/65R18 turns about 639 times and 275/65R18 about 629 times. Fewer turns per mile means the speedometer and odometer read low by roughly 1.6% unless they are recalibrated.
These figures are calculated from the size alone. Actual tires vary by brand and model, and fitment depends on your wheels and suspension, so check with a tire shop before buying.