255/35 R18
What size is 255/35 R18?
255/35 R18 has an overall diameter of about 25.03 in, a section width of 10.04 in and a sidewall height of 3.51 in. It turns roughly 806 times per mile. Below are the exact figures plus in-tolerance plus/minus sizes you can switch to safely.
- Overall diameter: 25.03 in.
- Section width: 10.04 in.
- Sidewall height: 3.51 in.
- Revolutions: 501 /km · 806 /mi.
- In-tolerance sizes: 195/65 R15 (-0.2%).
Fitment verdict
195/65 R15 stays within the configured tolerance for 255/35 R18: -0.2% diameter and -0.2% speedometer effect.
| Metric | This size: 255/35 R18 | Alternative: 195/65 R15 | Difference | Verdict |
|---|---|---|---|---|
| Overall diameter | 25.03 in | 24.98 in | -0.2% | Within tolerance |
| Section width | 10.04 in | 7.68 in | -2.36 in | Computed difference |
| Sidewall height | 3.51 in | 4.99 in | +1.48 in | Computed difference |
| Circumference | 78.63 in | 78.48 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 | 25.03 in |
|---|---|
| Section width | 10.04 in |
| Sidewall height | 3.51 in |
| Circumference | 78.63 in |
| Revolutions | 501 /km · 806 /mi |
In-tolerance sizes
Alternative sizes that stay within the safe diameter tolerance:
| Size | Diameter | Speedo | Verdict |
|---|---|---|---|
| 195/65 R15 | -0.2% | -0.2% | ✓ OK |
| 225/45 R17 | -0.2% | -0.2% | ✓ OK |
| 225/40 R18 | +0.2% | +0.2% | ✓ OK |
| 205/55 R16 | -0.6% | -0.6% | ✓ OK |
| 225/50 R16 | -0.7% | -0.7% | ✓ OK |
| 225/35 R19 | +0.7% | +0.7% | ✓ OK |
| 195/60 R16 | +0.7% | +0.7% | ✓ OK |
| 195/70 R14 | -1.1% | -1.1% | ✓ OK |
| 215/55 R16 | +1.1% | +1.1% | ✓ OK |
| 235/45 R17 | +1.2% | +1.2% | ✓ OK |
| 205/60 R15 | -1.4% | -1.4% | ✓ OK |
| 235/40 R18 | +1.5% | +1.5% | ✓ OK |
Compare sizes
- Within tolerance · Diameter -0.2%.
- Speedo @ 60: 60 mph → 59.9 mph.
- Sidewall +1.48 in · Width -2.36 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
- 25.03 in 24.98 in-0.05 in
- Sidewall
- 3.51 in 4.99 in+1.48 in
- Width
- 10.04 in 7.68 in-2.36 in
- Circumference
- 78.63 in 78.48 in-0.2%
- Revs / mile
- 806 807
- Speedo @ 60
- 60 mph 59.9 mph-0.2%
- Current —
255/35 R18 - New —
195/65 R15 - Grounded to the road: the axle rises -0.02 in.
Result report
255/35 R18 195/65 R15 · Within tolerance
Use this size when shopping: 195/65 R15
Geometric estimate. Always verify physical clearance (arches, suspension, brakes) before fitting.
Safe alternative sizes
| Size | Diameter | Speedo @ 100 | Use this |
|---|---|---|---|
−1″ 255/40R17 | +0.0% | +0.0% | |
OE 255/35R18 | +0.0% | +0.0% | |
+1″ 255/30R19 | -0.0% | -0.0% | |
+2″ 255/25R20 | -0.0% | -0.0% |
More tools
- How to read a tire size
- Plus sizing guide
- Speedometer error guide
- 255mm Section width guide
- /35 Aspect ratio guide
- Rim diameter 18"
- 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.