255/70R17 vs 275/55R20
275/55R20 is 22.0 mm taller than 255/70R17 in overall diameter (+2.8%), within the usual 3% limit, so it can replace it where the wheels and clearance allow. With 275/55R20 fitted, the speedometer reads 100 km/h when you are doing 102.8 km/h.
Dimensions side by side
| 255/70R17 | 275/55R20 | |
|---|---|---|
| Overall diameter | 789 mm (31.1″) | 811 mm (31.9″) |
| Section width | 255 mm | 275 mm |
| Sidewall height | 179 mm | 151 mm |
| Rim | 17″ | 20″ |
| Revolutions per km | 403 | 392 |
| In stock | 14 tires from $213.00 | 58 tires from $195.00 |
What changes
- Overall diameter: 275/55R20 is 22.0 mm taller (+2.8%).
- Speedometer: reads 100 km/h at an actual 102.8 km/h with 275/55R20.
- 275/55R20 is 20 mm wider, so check clearance and the recommended rim width.
- Wheel size changes from 17″ to 20″: you need wheels in the new size.
- Choose a load index at least as high as the one on your door placard.
Vehicles that came with both sizes
Vehicles that use 255/70R17
Vehicles that use 275/55R20
See every alternate size for 255/70R17
Frequently asked questions
Can I use 275/55R20 instead of 255/70R17?
Usually, yes: 275/55R20 is within 3% of the overall diameter of 255/70R17 (+2.8%). Use wheels of the right size and width, match or exceed the original load index, and check clearance at full steering lock.
How much does the speedometer change between 255/70R17 and 275/55R20?
With 275/55R20 instead of 255/70R17, the speedometer shows 100 km/h when you are actually doing 102.8 km/h.
Which vehicles came with both 255/70R17 and 275/55R20?
Both sizes were original equipment, on different trims or packages, on the 2014–2018 Chevrolet Silverado, 2014–2018 GMC Sierra, 2009 Ford F150.