235/55R20 vs 235/65R18
235/65R18 is 4.0 mm shorter than 235/55R20 in overall diameter (−0.5%), within the usual 3% limit, so it can replace it where the wheels and clearance allow. With 235/65R18 fitted, the speedometer reads 100 km/h when you are doing 99.5 km/h.
Dimensions side by side
| 235/55R20 | 235/65R18 | |
|---|---|---|
| Overall diameter | 767 mm (30.2″) | 763 mm (30.0″) |
| Section width | 235 mm | 235 mm |
| Sidewall height | 129 mm | 153 mm |
| Rim | 20″ | 18″ |
| Revolutions per km | 415 | 417 |
| In stock | 46 tires from $194.00 | 57 tires from $155.00 |
What changes
- Overall diameter: 235/65R18 is 4.0 mm shorter (−0.5%).
- Speedometer: reads 100 km/h at an actual 99.5 km/h with 235/65R18.
- 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 235/55R20
Vehicles that use 235/65R18
See every alternate size for 235/55R20
Frequently asked questions
Can I use 235/65R18 instead of 235/55R20?
Usually, yes: 235/65R18 is within 3% of the overall diameter of 235/55R20 (−0.5%). 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 235/55R20 and 235/65R18?
With 235/65R18 instead of 235/55R20, the speedometer shows 100 km/h when you are actually doing 99.5 km/h.
Which vehicles came with both 235/55R20 and 235/65R18?
Both sizes were original equipment, on different trims or packages, on the 2017–2024 Cadillac XT5, 2019–2024 Chevrolet Blazer, 2020–2024 Cadillac XT6, 2017–2023 GMC Acadia, 2012, 2021–2023 Nissan Murano, 2016–2022 Lexus RX.