255/40 R19 vs 235/50 R18
255/40 R19 vs 235/50 R18
235/50 R18 stays within the configured tolerance for 255/40 R19: +0.8% diameter and +0.8% speedometer effect.
Fitment verdict
235/50 R18 stays within the configured tolerance for 255/40 R19: +0.8% diameter and +0.8% speedometer effect.
| Metric | This size: 255/40 R19 | Alternative: 235/50 R18 | Difference | Verdict |
|---|---|---|---|---|
| Overall diameter | 27.03 in | 27.25 in | +0.8% | Within tolerance |
| Section width | 10.04 in | 9.25 in | -0.79 in | Computed difference |
| Sidewall height | 4.02 in | 4.63 in | +0.61 in | Computed difference |
| Circumference | 84.92 in | 85.61 in | +0.8% | Within tolerance |
| Speedo | 0.0% | +0.8% | +0.8% | Within tolerance |
Compare sizes
Looks valid
Looks valid
Units
✓ Within toleranceDiameter +0.8% (+0.22 in) · US (~3%)
- Within tolerance · Diameter +0.8%.
- Speedo @ 60: 60 mph → 60.5 mph.
- Sidewall +0.61 in · Width -0.79 in.
Diameter+0.8%+0.22 in
Speedo @ 60+0.8%60 mph → 60.5 mph
Sidewall+0.61 inWidth -0.79 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
- 27.03 in 27.25 in+0.22 in
- Sidewall
- 4.02 in 4.63 in+0.61 in
- Width
- 10.04 in 9.25 in-0.79 in
- Circumference
- 84.92 in 85.61 in+0.8%
- Revs / mile
- 746 740
- Speedo @ 60
- 60 mph 60.5 mph+0.8%
- Current —
255/40 R19 - New —
235/50 R18 - Grounded to the road: the axle rises +0.11 in.
Result report
255/40 R19 235/50 R18 · Within tolerance
Use this size when shopping: 235/50 R18
Geometric estimate. Always verify physical clearance (arches, suspension, brakes) before fitting.
Safe alternative sizes
| Size | Diameter | Speedo @ 100 | Use this |
|---|---|---|---|
−1″ 255/45R18 | +0.0% | +0.0% | |
OE 255/40R19 | +0.0% | +0.0% | |
+1″ 255/35R20 | -0.0% | -0.0% | |
+2″ 255/30R21 | -0.0% | -0.0% |
255/40 R19 · 235/50 R18 · Methodology
What changed
- Reviewed deterministic geometry, load/speed references, sitemap inclusion and localized page shell.