225/50 R16 vs 225/40 R18
225/50 R16 vs 225/40 R18
225/40 R18 stays within the configured tolerance for 225/50 R16: +0.9% diameter and +0.9% speedometer effect.
Fitment verdict
225/40 R18 stays within the configured tolerance for 225/50 R16: +0.9% diameter and +0.9% speedometer effect.
| Metric | This size: 225/50 R16 | Alternative: 225/40 R18 | Difference | Verdict |
|---|---|---|---|---|
| Overall diameter | 24.86 in | 25.09 in | +0.9% | Within tolerance |
| Section width | 8.86 in | 8.86 in | 0.00 in | Computed difference |
| Sidewall height | 4.43 in | 3.54 in | -0.89 in | Computed difference |
| Circumference | 78.09 in | 78.81 in | +0.9% | Within tolerance |
| Speedo | 0.0% | +0.9% | +0.9% | Within tolerance |
Compare sizes
Looks valid
Looks valid
Units
✓ Within toleranceDiameter +0.9% (+0.23 in) · US (~3%)
- Within tolerance · Diameter +0.9%.
- Speedo @ 60: 60 mph → 60.6 mph.
- Sidewall -0.89 in · Width +0.00 in.
Diameter+0.9%+0.23 in
Speedo @ 60+0.9%60 mph → 60.6 mph
Sidewall-0.89 inWidth +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
- 24.86 in 25.09 in+0.23 in
- Sidewall
- 4.43 in 3.54 in-0.89 in
- Width
- 8.86 in 8.86 in+0.00 in
- Circumference
- 78.09 in 78.81 in+0.9%
- Revs / mile
- 811 804
- Speedo @ 60
- 60 mph 60.6 mph+0.9%
- Current —
225/50 R16 - New —
225/40 R18 - Grounded to the road: the axle rises +0.11 in.
Result report
225/50 R16 225/40 R18 · Within tolerance
Use this size when shopping: 225/40 R18
Geometric estimate. Always verify physical clearance (arches, suspension, brakes) before fitting.
Safe alternative sizes
| Size | Diameter | Speedo @ 100 | Use this |
|---|---|---|---|
−1″ 315/40R15 | +0.3% | +0.3% | |
OE 225/50R16 | +0.0% | +0.0% | |
+1″ 285/35R17 | -0.0% | -0.0% | |
+2″ 145/60R18 | -0.0% | -0.0% |
225/50 R16 · 225/40 R18 · Methodology
What changed
- Reviewed deterministic geometry, load/speed references, sitemap inclusion and localized page shell.