275/45 R20
What size is 275/45 R20?
275/45 R20 has an overall diameter of about 29.74 in, a section width of 10.83 in and a sidewall height of 4.87 in. It turns roughly 678 times per mile. Below are the exact figures plus in-tolerance plus/minus sizes you can switch to safely.
- Overall diameter: 29.74 in.
- Section width: 10.83 in.
- Sidewall height: 4.87 in.
- Revolutions: 421 /km · 678 /mi.
- In-tolerance sizes: 285/35 R22 (+0.4%).
Fitment verdict
285/35 R22 stays within the configured tolerance for 275/45 R20: +0.4% diameter and +0.4% speedometer effect.
| Metric | This size: 275/45 R20 | Alternative: 285/35 R22 | Difference | Verdict |
|---|---|---|---|---|
| Overall diameter | 29.74 in | 29.85 in | +0.4% | Within tolerance |
| Section width | 10.83 in | 11.22 in | +0.39 in | Computed difference |
| Sidewall height | 4.87 in | 3.93 in | -0.94 in | Computed difference |
| Circumference | 93.44 in | 93.79 in | +0.4% | Within tolerance |
| Speedo | 0.0% | +0.4% | +0.4% | 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 | 29.74 in |
|---|---|
| Section width | 10.83 in |
| Sidewall height | 4.87 in |
| Circumference | 93.44 in |
| Revolutions | 421 /km · 678 /mi |
In-tolerance sizes
Alternative sizes that stay within the safe diameter tolerance:
| Size | Diameter | Speedo | Verdict |
|---|---|---|---|
| 285/35 R22 | +0.4% | +0.4% | ✓ OK |
| 305/40 R20 | -0.5% | -0.5% | ✓ OK |
| 245/60 R18 | -0.6% | -0.6% | ✓ OK |
| 245/65 R17 | -0.7% | -0.7% | ✓ OK |
| 235/70 R17 | +0.7% | +0.7% | ✓ OK |
| 245/70 R16 | -0.8% | -0.8% | ✓ OK |
| 235/65 R18 | +1.0% | +1.0% | ✓ OK |
| 255/50 R20 | +1.0% | +1.0% | ✓ OK |
| 255/65 R17 | +1.0% | +1.0% | ✓ OK |
| 265/50 R19 | -1.0% | -1.0% | ✓ OK |
| 265/45 R20 | -1.2% | -1.2% | ✓ OK |
| 295/40 R20 | -1.5% | -1.5% | ✓ OK |
Compare sizes
- Within tolerance · Diameter +0.4%.
- Speedo @ 60: 60 mph → 60.2 mph.
- Sidewall -0.94 in · Width +0.39 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
- 29.74 in 29.85 in+0.11 in
- Sidewall
- 4.87 in 3.93 in-0.94 in
- Width
- 10.83 in 11.22 in+0.39 in
- Circumference
- 93.44 in 93.79 in+0.4%
- Revs / mile
- 678 676
- Speedo @ 60
- 60 mph 60.2 mph+0.4%
- Current —
275/45 R20 - New —
285/35 R22 - Grounded to the road: the axle rises +0.06 in.
Result report
275/45 R20 285/35 R22 · Within tolerance
Use this size when shopping: 285/35 R22
Geometric estimate. Always verify physical clearance (arches, suspension, brakes) before fitting.
Safe alternative sizes
| Size | Diameter | Speedo @ 100 | Use this |
|---|---|---|---|
−1″ 195/70R19 | +0.0% | +0.0% | |
OE 275/45R20 | +0.0% | +0.0% | |
+1″ 185/60R21 | -0.0% | -0.0% | |
+2″ 245/40R22 | -0.1% | -0.1% |
More tools
- How to read a tire size
- Plus sizing guide
- Speedometer error guide
- 275mm Section width guide
- /45 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.