275/55 R20 Tyre Size — Meaning, Fitment & Alternatives
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What 275/55 R20 means
275/55 R20 is a 275 mm wide tyre with a sidewall 55% of that width (151 mm), on a 20-inch rim. Overall diameter works out at about 810 mm (31.9 in). It typically fits SUVs, 4x4s and pickups — vehicles in the class of the Land Cruiser, Ranger or RAV4 depending on exact size.
UK: check prices for 275/55 R20 tyres at Tirendo US: check 275/55 R20 prices at WheelHero
275/55 R20 broken down
| Code part | Value | Meaning |
|---|---|---|
| Width | 275 | Section width in millimetres, sidewall to sidewall |
| Profile (aspect ratio) | 55 | Sidewall height as a percentage of width — 151 mm here |
| R | Radial | Radial construction (standard on modern car tyres) |
| Rim | 20 | Wheel diameter in inches (508 mm) |
Computed dimensions
| Measure | Value |
|---|---|
| Overall diameter | 810 mm (31.9 in) |
| Circumference | 2546 mm (100.2 in) |
| Sidewall height | 151 mm |
| Revolutions per mile | ≈ 632 |
| Revolutions per km | ≈ 393 |
These are computed reference values from the size code arithmetic — actual measurements vary slightly by brand and model. Working in different units? Convert mm to inches with the unit converters at 247QuickTools.
Tyre Owner Essentials
Typical vehicles
Sizes in this family split between highway-terrain and all-terrain patterns. The same size can carry very different load ratings, so match the placard's load index, not just the size. To confirm the exact original-equipment sizes for your car, look up your car's full specs, including OE tyre sizes, at 247VehicleCheck.
Checking your current tread? Owners often keep a tread depth gauge in the glovebox — UK legal minimum is 1.6 mm across the central three-quarters of the tread.
Speed and load ratings commonly sold in 275/55 R20
Tyres in this size are usually sold in higher speed ratings — V (149 mph), W (168 mph) and Y (186 mph) — with load indices matched to performance and premium models. See the full speed rating table and load index table for what each code is rated to.
Alternative & equivalent sizes (±3% diameter)
Sizes within ±3% of this tyre's 810 mm overall diameter keep your speedometer and gearing close to accurate. Always check clearance, rim width compatibility and load rating before switching, and never mix constructions across an axle.
| Alternative size | Overall diameter | Difference |
|---|---|---|
| 255/70 R18 | 814 mm | +0.5% |
| 275/45 R22 | 806 mm | -0.5% |
| 275/65 R18 | 815 mm | +0.5% |
| 285/45 R22 | 815 mm | +0.6% |
| 265/75 R16 | 804 mm | -0.8% |
| 265/70 R17 | 803 mm | -1.0% |
| 305/40 R22 | 803 mm | -1.0% |
| 265/65 R18 | 802 mm | -1.1% |
| 285/60 R18 | 799 mm | -1.4% |
| 285/65 R18 | 828 mm | +2.1% |
Tyre pressure for 275/55 R20
Correct pressure depends on your vehicle and load, not on the tyre size alone — always follow the placard inside the driver's door or the handbook. Typical car pressures fall between 30 and 36 psi. For psi-to-bar maths, the calculators at 247Calculators can help. A monthly check with an accurate gauge catches slow leaks before they wear the shoulders.
Recommended Accessories
FAQ
What does 275/55 R20 mean?
275/55 R20 means the tyre is 275 mm wide, its sidewall is 55% of that width (151 mm), and it fits a 20-inch wheel. The R stands for radial construction.
What is the overall diameter of a 275/55 R20 tyre?
About 810 mm (31.9 inches), computed from the size code: 20-inch rim plus two sidewalls of 151 mm. Actual measurements vary slightly by brand.
Can I fit a different size instead of 275/55 R20?
Only if the alternative stays within about ±3%% of the original overall diameter, fits your rim width, clears the bodywork and meets the placard's load and speed ratings. When in doubt, keep the placard size.
What pressure should 275/55 R20 tyres run at?
Pressure is set by the vehicle, not the tyre size — check the placard inside the driver's door or your handbook. Typical car values fall between 30 and 36 psi.
Related pages on this site
Last updated:
Data: computed reference values (ETRTO tyre-size arithmetic), build date 22 July 2026. Reference only — always follow your vehicle manufacturer's placard or handbook.