255/50 R20
What size is 255/50 R20?
255/50 R20 has an overall diameter of about 30.04 in, a section width of 10.04 in and a sidewall height of 5.02 in. It turns roughly 671 times per mile. Below are the exact figures plus in-tolerance plus/minus sizes you can switch to safely.
- Overall diameter: 30.04 in.
- Section width: 10.04 in.
- Sidewall height: 5.02 in.
- Revolutions: 417 /km · 671 /mi.
- In-tolerance sizes: 255/65 R17 (+0.0%).
Fitment verdict
255/65 R17 stays within the configured tolerance for 255/50 R20: 0.0% diameter and 0.0% speedometer effect.
| Metric | This size: 255/50 R20 | Alternative: 255/65 R17 | Difference | Verdict |
|---|---|---|---|---|
| Overall diameter | 30.04 in | 30.05 in | 0.0% | Within tolerance |
| Section width | 10.04 in | 10.04 in | 0.00 in | Computed difference |
| Sidewall height | 5.02 in | 6.53 in | +1.51 in | Computed difference |
| Circumference | 94.37 in | 94.41 in | 0.0% | Within tolerance |
| Speedo | 0.0% | 0.0% | 0.0% | 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 | 30.04 in |
|---|---|
| Section width | 10.04 in |
| Sidewall height | 5.02 in |
| Circumference | 94.37 in |
| Revolutions | 417 /km · 671 /mi |
In-tolerance sizes
Alternative sizes that stay within the safe diameter tolerance:
| Size | Diameter | Speedo | Verdict |
|---|---|---|---|
| 255/65 R17 | +0.0% | +0.0% | ✓ OK |
| 235/65 R18 | -0.0% | -0.0% | ✓ OK |
| 235/70 R17 | -0.3% | -0.3% | ✓ OK |
| 285/35 R22 | -0.6% | -0.6% | ✓ OK |
| 275/45 R20 | -1.0% | -1.0% | ✓ OK |
| 265/40 R22 | +1.0% | +1.0% | ✓ OK |
| 265/45 R21 | +1.2% | +1.2% | ✓ OK |
| 265/50 R20 | +1.3% | +1.3% | ✓ OK |
| 305/40 R20 | -1.4% | -1.4% | ✓ OK |
| 245/70 R17 | +1.5% | +1.5% | ✓ OK |
| 245/60 R18 | -1.5% | -1.5% | ✓ OK |
| 265/60 R18 | +1.6% | +1.6% | ✓ OK |
Compare sizes
- Within tolerance · Diameter +0.0%.
- Speedo @ 60: 60 mph → 60.0 mph.
- Sidewall +1.51 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
- 30.04 in 30.05 in+0.01 in
- Sidewall
- 5.02 in 6.53 in+1.51 in
- Width
- 10.04 in 10.04 in+0.00 in
- Circumference
- 94.37 in 94.41 in+0.0%
- Revs / mile
- 671 671
- Speedo @ 60
- 60 mph 60.0 mph+0.0%
- Current —
255/50 R20 - New —
255/65 R17 - Grounded to the road: the axle rises +0.01 in.
Result report
255/50 R20 255/65 R17 · Within tolerance
Use this size when shopping: 255/65 R17
Geometric estimate. Always verify physical clearance (arches, suspension, brakes) before fitting.
Safe alternative sizes
| Size | Diameter | Speedo @ 100 | Use this |
|---|---|---|---|
−1″ 255/55R19 | +0.0% | +0.0% | |
OE 255/50R20 | +0.0% | +0.0% | |
+1″ 255/45R21 | -0.0% | -0.0% | |
+2″ 255/40R22 | -0.0% | -0.0% |
More tools
- How to read a tire size
- Plus sizing guide
- Speedometer error guide
- 255mm Section width guide
- /50 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.