275/70R18 vs 285/70R18
285/70R18 is 0.55 inches taller than 275/70R18 and 10 mm (0.4 in) wider.
+1.7% height. Inside the usual 3% rule for a swap.
| Measurement | 275/70R18 | 285/70R18 | Difference |
|---|---|---|---|
| Overall height | 33.2 in | 33.7 in | +0.55 in (+1.7%) |
| Section width | 10.8 in | 11.2 in | +0.39 in (+10 mm) |
| Sidewall height | 7.6 in | 7.9 in | +0.28 in |
| Circumference | 104.2 in | 105.9 in | +1.7 in |
| Revolutions per mile | 608 | 598 | −10 |
| Ride height | +0.28 in |
Speedometer
With 285/70R18 fitted, a speedometer set up for 275/70R18 shows the first number when you are really doing the second.
- 3030.5 mph
- 4545.7 mph
- 6061.0 mph
- 7576.2 mph
The two sizes
275/70R18 is 33.2 inches tall with a 7.6-inch sidewall. 285/70R18 is 33.7 inches tall with a 7.9-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, 275/70R18 or 285/70R18?
285/70R18 is taller: 33.7 inches against 33.2. 285/70R18 is wider, at 285 mm.
Can I replace 275/70R18 with 285/70R18?
On height, yes: the difference is 1.7%, 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 285/70R18 on a vehicle set up for 275/70R18, the speedometer shows 60 mph at a true 61.0 mph, and 70 at 71.2.