275/65R20 vs 275/70R18
275/70R18 is 24.0 mm shorter than 275/65R20 in overall diameter (−2.8%), within the usual 3% limit, so it can replace it where the wheels and clearance allow. With 275/70R18 fitted, the speedometer reads 100 km/h when you are doing 97.2 km/h.
Dimensions side by side
| 275/65R20 | 275/70R18 | |
|---|---|---|
| Overall diameter | 866 mm (34.1″) | 842 mm (33.1″) |
| Section width | 275 mm | 275 mm |
| Sidewall height | 179 mm | 193 mm |
| Rim | 20″ | 18″ |
| Revolutions per km | 368 | 378 |
| In stock | 3 tires from $387.00 | 3 tires from $270.00 |
What changes
- Overall diameter: 275/70R18 is 24.0 mm shorter (−2.8%).
- Speedometer: reads 100 km/h at an actual 97.2 km/h with 275/70R18.
- Wheel size changes from 20″ to 18″: 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 275/65R20
Vehicles that use 275/70R18
See every alternate size for 275/65R20
Frequently asked questions
Can I use 275/70R18 instead of 275/65R20?
Usually, yes: 275/70R18 is within 3% of the overall diameter of 275/65R20 (−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 275/65R20 and 275/70R18?
With 275/70R18 instead of 275/65R20, the speedometer shows 100 km/h when you are actually doing 97.2 km/h.
Which vehicles came with both 275/65R20 and 275/70R18?
Both sizes were original equipment, on different trims or packages, on the 2005–2024 Ford F250, 2006–2024 Ford F350, 2020–2024 GMC Sierra, 2020–2024 Chevrolet Silverado.