275/55 R20
What size is 275/55 R20?
275/55 R20 has an overall diameter of about 31.91 in, a section width of 10.83 in and a sidewall height of 5.95 in. It turns roughly 632 times per mile. Below are the exact figures plus in-tolerance plus/minus sizes you can switch to safely.
- Overall diameter: 31.91 in.
- Section width: 10.83 in.
- Sidewall height: 5.95 in.
- Revolutions: 393 /km · 632 /mi.
- In-tolerance sizes: 275/65 R18 (+0.5%).
Fitment verdict
275/65 R18 stays within the configured tolerance for 275/55 R20: +0.5% diameter and +0.5% speedometer effect.
| Metric | This size: 275/55 R20 | Alternative: 275/65 R18 | Difference | Verdict |
|---|---|---|---|---|
| Overall diameter | 31.91 in | 32.07 in | +0.5% | Within tolerance |
| Section width | 10.83 in | 10.83 in | 0.00 in | Computed difference |
| Sidewall height | 5.95 in | 7.04 in | +1.08 in | Computed difference |
| Circumference | 100.25 in | 100.77 in | +0.5% | Within tolerance |
| Speedo | 0.0% | +0.5% | +0.5% | Within tolerance |
Seasonal check
Planning a long summer drive?
Use the budget and running-cost tools before a trip, especially if the current tyres are worn or the replacement size changes diameter.
Specification
| Overall diameter | 31.91 in |
|---|---|
| Section width | 10.83 in |
| Sidewall height | 5.95 in |
| Circumference | 100.25 in |
| Revolutions | 393 /km · 632 /mi |
In-tolerance sizes
Alternative sizes that stay within the safe diameter tolerance:
| Size | Diameter | Speedo | Verdict |
|---|---|---|---|
| 275/65 R18 | +0.5% | +0.5% | ✓ OK |
| 275/45 R22 | -0.5% | -0.5% | ✓ OK |
| 285/45 R22 | +0.6% | +0.6% | ✓ OK |
| 265/70 R17 | -1.0% | -1.0% | ✓ OK |
| 305/40 R22 | -1.0% | -1.0% | ✓ OK |
| 265/65 R18 | -1.1% | -1.1% | ✓ OK |
| 285/60 R18 | -1.4% | -1.4% | ✓ OK |
| 285/65 R18 | +2.1% | +2.1% | ✓ OK |
| 285/50 R20 | -2.2% | -2.2% | ✓ OK |
| 305/45 R22 | +2.8% | +2.8% | ✓ OK |
| 31x10.50 R15 | -2.9% | -2.9% | ✓ OK |
| 31x10.50 R16 | -2.9% | -2.9% | ✓ OK |
Compare sizes
- Within tolerance · Diameter +0.5%.
- Speedo @ 60: 60 mph → 60.3 mph.
- Sidewall +1.08 in · Width +0.00 in.
How this result is calculated
Computed from nominal tire-size geometry: diameter, circumference and speedometer error. It does not check wheel-arch, suspension or brake clearance.
Methodology- Diameter
- 31.91 in 32.07 in+0.17 in
- Sidewall
- 5.95 in 7.04 in+1.08 in
- Width
- 10.83 in 10.83 in+0.00 in
- Circumference
- 100.25 in 100.77 in+0.5%
- Revs / mile
- 632 629
- Speedo @ 60
- 60 mph 60.3 mph+0.5%
- Current —
275/55 R20 - New —
275/65 R18 - Grounded to the road: the axle rises +0.08 in.
Result report
275/55 R20 275/65 R18 · Within tolerance
Use this size when shopping: 275/65 R18
Geometric estimate. Always verify physical clearance (arches, suspension, brakes) before fitting.
Safe alternative sizes
| Size | Diameter | Speedo @ 100 | Use this |
|---|---|---|---|
−1″ 205/80R19 | +0.0% | +0.0% | |
OE 275/55R20 | +0.0% | +0.0% | |
+1″ 185/75R21 | +0.0% | +0.0% | |
+2″ 315/40R22 | +0.0% | +0.0% |
More tools
- How to read a tire size
- Plus sizing guide
- Speedometer error guide
- 275mm Section width guide
- /55 Aspect ratio guide
- Rim diameter 20"
- Load index chart
- Speed rating chart
- Rim width and tyre fitment guide
- Wheel offset guide
- Wheel spacers guide
- Tyre pressure for heavy loads and towing
What changed
- Reviewed deterministic geometry, load/speed references, sitemap inclusion and localized page shell.