285/70R17 vs 285/75R17
285/75R17 is 1.1 inches taller and 0.0 inches wider. When your speedometer says 60 mph, you'd really be doing 62.1.
I have 285/70R17
I'm looking at 285/75R17
Possible, with caveats
1.1 in taller. At 60 mph on the speedometer you'd really be doing 62.1.
- More than 3% taller. Expect a noticeable speedometer error, and check that it clears the fenders and suspension when turning. Trucks often need a leveling kit.
285/70R17 now 285/75R17 newTo scale
At an indicated 60 mph you're really doing 62.1 mph
+1.12″
Height
+0.00″
Width
+0.56″
Sidewall
All measurements
| 285/70R17 | 285/75R17 | Change | |
|---|---|---|---|
| Overall height | 32.71″ | 33.83″ | +1.12″ |
| Section width | 11.22″ | 11.22″ | +0.00″ |
| Sidewall height | 7.85″ | 8.42″ | +0.56″ |
| Wheel size | 17″ | 17″ | same |
| Distance per turn | 102.76″ | 106.28″ | +3.53″ |
| Turns per mile | 617 | 596 | −20 |
Speedometer after switching
Your speedometer is calibrated for 285/70R17. On 285/75R17:
| Speedometer says | You're really doing |
|---|---|
| 25 mph | 25.9 mph |
| 35 mph | 36.2 mph |
| 45 mph | 46.5 mph |
| 55 mph | 56.9 mph |
| 65 mph | 67.2 mph |
| 75 mph | 77.6 mph |
What changes on the vehicle
- Ride height goes up about 0.56″ (half the height difference).
- The tire turns 20 fewer times per mile, so your odometer will read low by about 3.4%.
- The sidewall is 0.56″ taller, on the same wheels.