185/55 R15
What size is 185/55 R15?
185/55 R15 has an overall diameter of about 23.01 in, a section width of 7.28 in and a sidewall height of 4.01 in. It turns roughly 876 times per mile. Below are the exact figures plus in-tolerance plus/minus sizes you can switch to safely.
- Overall diameter: 23.01 in.
- Section width: 7.28 in.
- Sidewall height: 4.01 in.
- Revolutions: 545 /km · 876 /mi.
- In-tolerance sizes: 175/65 R14 (-0.2%).
Fitment verdict
175/65 R14 stays within the configured tolerance for 185/55 R15: -0.2% diameter and -0.2% speedometer effect.
| Metric | This size: 185/55 R15 | Alternative: 175/65 R14 | Difference | Verdict |
|---|---|---|---|---|
| Overall diameter | 23.01 in | 22.96 in | -0.2% | Within tolerance |
| Section width | 7.28 in | 6.89 in | -0.39 in | Computed difference |
| Sidewall height | 4.01 in | 4.48 in | +0.47 in | Computed difference |
| Circumference | 72.29 in | 72.12 in | -0.2% | Within tolerance |
| Speedo | 0.0% | -0.2% | -0.2% | 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 | 23.01 in |
|---|---|
| Section width | 7.28 in |
| Sidewall height | 4.01 in |
| Circumference | 72.29 in |
| Revolutions | 545 /km · 876 /mi |
In-tolerance sizes
Alternative sizes that stay within the safe diameter tolerance:
| Size | Diameter | Speedo | Verdict |
|---|---|---|---|
| 175/65 R14 | -0.2% | -0.2% | ✓ OK |
| 165/70 R14 | +0.4% | +0.4% | ✓ OK |
| 185/60 R14 | -1.2% | -1.2% | ✓ OK |
| 195/55 R15 | +1.9% | +1.9% | ✓ OK |
| 185/65 R14 | +2.0% | +2.0% | ✓ OK |
Compare sizes
- Within tolerance · Diameter -0.2%.
- Speedo @ 60: 60 mph → 59.9 mph.
- Sidewall +0.47 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
- 23.01 in 22.96 in-0.06 in
- Sidewall
- 4.01 in 4.48 in+0.47 in
- Width
- 7.28 in 6.89 in-0.39 in
- Circumference
- 72.29 in 72.12 in-0.2%
- Revs / mile
- 876 879
- Speedo @ 60
- 60 mph 59.9 mph-0.2%
- Current —
185/55 R15 - New —
175/65 R14 - Grounded to the road: the axle rises -0.03 in.
Result report
185/55 R15 175/65 R14 · Within tolerance
Use this size when shopping: 175/65 R14
Geometric estimate. Always verify physical clearance (arches, suspension, brakes) before fitting.
Safe alternative sizes
| Size | Diameter | Speedo @ 100 | Use this |
|---|---|---|---|
−1″ 255/45R14 | +0.1% | +0.1% | |
OE 185/55R15 | +0.0% | +0.0% | |
+1″ 255/35R16 | +0.1% | +0.1% | |
+2″ 305/25R17 | -0.0% | -0.0% |
More tools
- How to read a tire size
- Plus sizing guide
- Speedometer error guide
- 185mm Section width guide
- /55 Aspect ratio guide
- Rim diameter 15"
- 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.