255/35R18 vs 275/35R18
275/35R18 is 14.0 mm taller than 255/35R18 in overall diameter (+2.2%), within the usual 3% limit, so it can replace it where the wheels and clearance allow. With 275/35R18 fitted, the speedometer reads 100 km/h when you are doing 102.2 km/h.
Dimensions side by side
| 255/35R18 | 275/35R18 | |
|---|---|---|
| Overall diameter | 636 mm (25.0″) | 650 mm (25.6″) |
| Section width | 255 mm | 275 mm |
| Sidewall height | 89 mm | 96 mm |
| Rim | 18″ | 18″ |
| Revolutions per km | 500 | 490 |
| In stock | 13 tires from $116.00 | 8 tires from $280.00 |
What changes
- Overall diameter: 275/35R18 is 14.0 mm taller (+2.2%).
- Speedometer: reads 100 km/h at an actual 102.2 km/h with 275/35R18.
- 275/35R18 is 20 mm wider, so check clearance and the recommended rim width.
- Choose a load index at least as high as the one on your door placard.
Vehicles that came with both sizes
Vehicles that use 255/35R18
Vehicles that use 275/35R18
See every alternate size for 255/35R18
Frequently asked questions
Can I use 275/35R18 instead of 255/35R18?
Usually, yes: 275/35R18 is within 3% of the overall diameter of 255/35R18 (+2.2%). 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 255/35R18 and 275/35R18?
With 275/35R18 instead of 255/35R18, the speedometer shows 100 km/h when you are actually doing 102.2 km/h.
Which vehicles came with both 255/35R18 and 275/35R18?
Both sizes were original equipment, on different trims or packages, on the 2022–2024 Cadillac CT4, 2016–2019 Cadillac ATS-V, 2016–2019 Cadillac ATS.