245/60 R18
What size is 245/60 R18?
245/60 R18 has an overall diameter of about 29.57 in, a section width of 9.65 in and a sidewall height of 5.79 in. It turns roughly 682 times per mile. Below are the exact figures plus in-tolerance plus/minus sizes you can switch to safely.
- Overall diameter: 29.57 in.
- Section width: 9.65 in.
- Sidewall height: 5.79 in.
- Revolutions: 424 /km · 682 /mi.
- In-tolerance sizes: 305/40 R20 (+0.1%).
Fitment verdict
305/40 R20 stays within the configured tolerance for 245/60 R18: +0.1% diameter and +0.1% speedometer effect.
| Metric | This size: 245/60 R18 | Alternative: 305/40 R20 | Difference | Verdict |
|---|---|---|---|---|
| Overall diameter | 29.57 in | 29.61 in | +0.1% | Within tolerance |
| Section width | 9.65 in | 12.01 in | +2.36 in | Computed difference |
| Sidewall height | 5.79 in | 4.80 in | -0.98 in | Computed difference |
| Circumference | 92.91 in | 93.01 in | +0.1% | Within tolerance |
| Speedo | 0.0% | +0.1% | +0.1% | 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 | 29.57 in |
|---|---|
| Section width | 9.65 in |
| Sidewall height | 5.79 in |
| Circumference | 92.91 in |
| Revolutions | 424 /km · 682 /mi |
In-tolerance sizes
Alternative sizes that stay within the safe diameter tolerance:
| Size | Diameter | Speedo | Verdict |
|---|---|---|---|
| 305/40 R20 | +0.1% | +0.1% | ✓ OK |
| 245/65 R17 | -0.1% | -0.1% | ✓ OK |
| 245/70 R16 | -0.2% | -0.2% | ✓ OK |
| 265/50 R19 | -0.5% | -0.5% | ✓ OK |
| 275/45 R20 | +0.6% | +0.6% | ✓ OK |
| 265/45 R20 | -0.6% | -0.6% | ✓ OK |
| 285/35 R22 | +0.9% | +0.9% | ✓ OK |
| 295/40 R20 | -1.0% | -1.0% | ✓ OK |
| 235/70 R17 | +1.3% | +1.3% | ✓ OK |
| 235/55 R19 | -1.3% | -1.3% | ✓ OK |
| 295/35 R21 | -1.5% | -1.5% | ✓ OK |
| 235/65 R18 | +1.5% | +1.5% | ✓ OK |
Compare sizes
- Within tolerance · Diameter +0.1%.
- Speedo @ 60: 60 mph → 60.1 mph.
- Sidewall -0.98 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
- 29.57 in 29.61 in+0.03 in
- Sidewall
- 5.79 in 4.80 in-0.98 in
- Width
- 9.65 in 12.01 in+2.36 in
- Circumference
- 92.91 in 93.01 in+0.1%
- Revs / mile
- 682 681
- Speedo @ 60
- 60 mph 60.1 mph+0.1%
- Current —
245/60 R18 - New —
305/40 R20 - Grounded to the road: the axle rises +0.02 in.
Result report
245/60 R18 305/40 R20 · Within tolerance
Use this size when shopping: 305/40 R20
Geometric estimate. Always verify physical clearance (arches, suspension, brakes) before fitting.
Safe alternative sizes
| Size | Diameter | Speedo @ 100 | Use this |
|---|---|---|---|
−1″ 355/45R17 | +0.0% | +0.0% | |
OE 245/60R18 | +0.0% | +0.0% | |
+1″ 335/40R19 | -0.1% | -0.1% | |
+2″ 305/40R20 | +0.1% | +0.1% |
More tools
- How to read a tire size
- Plus sizing guide
- Speedometer error guide
- 245mm Section width guide
- /60 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.