275/55R20 vs 285/55R20
285/55R20 is 0.43 inches taller than 275/55R20 and 10 mm (0.4 in) wider.
+1.4% height. Inside the usual 3% rule for a swap.
| Measurement | 275/55R20 | 285/55R20 | Difference |
|---|---|---|---|
| Overall height | 31.9 in | 32.3 in | +0.43 in (+1.4%) |
| Section width | 10.8 in | 11.2 in | +0.39 in (+10 mm) |
| Sidewall height | 6.0 in | 6.2 in | +0.22 in |
| Circumference | 100.2 in | 101.6 in | +1.4 in |
| Revolutions per mile | 632 | 624 | −8 |
| Ride height | +0.22 in |
Speedometer
With 285/55R20 fitted, a speedometer set up for 275/55R20 shows the first number when you are really doing the second.
- 3030.4 mph
- 4545.6 mph
- 6060.8 mph
- 7576.0 mph
The two sizes
275/55R20 is 31.9 inches tall with a 6.0-inch sidewall. 285/55R20 is 32.3 inches tall with a 6.2-inch sidewall. A taller sidewall rides softer and gives more ground clearance; a shorter one turns in more sharply. Try other pairs in the tire size calculator.
More comparisons
Questions
Which is bigger, 275/55R20 or 285/55R20?
285/55R20 is taller: 32.3 inches against 31.9. 285/55R20 is wider, at 285 mm.
Can I replace 275/55R20 with 285/55R20?
On height, yes: the difference is 1.4%, inside the usual 3% rule. Check that the extra width clears the suspension and suits your rim width.
How much does the speedometer change?
With 285/55R20 on a vehicle set up for 275/55R20, the speedometer shows 60 mph at a true 60.8 mph, and 70 at 71.0.