31x10.50 R15 vs 33x12.50 R15
31x10.50 R15 vs 33x12.50 R15
33x12.50 R15 is outside the configured tolerance for 31x10.50 R15: +6.5% diameter and +6.5% speedometer effect.
Geometric comparison
33x12.50 R15 is outside the configured tolerance for 31x10.50 R15: +6.5% diameter and +6.5% speedometer effect.
| Metric | This size: 31x10.50 R15 | Alternative: 33x12.50 R15 | Difference | Verdict |
|---|---|---|---|---|
| Overall diameter | 31.00 in | 33.00 in | +6.5% | Too tall |
| Section width | 10.50 in | 12.50 in | +2.00 in | Computed difference |
| Sidewall height | 8.00 in | 9.00 in | +1.00 in | Computed difference |
| Circumference | 97.39 in | 103.67 in | +6.5% | Too tall |
| Speedo | 0.0% | +6.5% | +6.5% | Outside tolerance |
Compare sizes
Looks valid
Looks valid
Units
Not recommendedOut of tolerance · Diameter +6.5% (+2.00 in) · US (~3%)
- Not recommended · This rating covers tire geometry only, not vehicle compatibility.
- Diameter +6.5% · Ride-height change +1.00 in.
- Speedometer reads low · 60 mph → 63.9 mph.
- Sidewall +1.00 in · Width +2.00 in.
Diameter+6.5%+2.00 in
Speedo @ 60+6.5%60 mph → 63.9 mph
Sidewall+1.00 inWidth +2.00 in
Ride-height change+1.00 inDiameter ÷ 2
How this result is calculated
Computed from nominal tire-size geometry: diameter, circumference and speedometer error. It does not check vehicle placard approval, load/speed rating, rim-width range, wheel-arch, suspension or brake clearance.
MethodologyBefore fitting
- Check the vehicle placard and owner’s manual first.
- Match or exceed the required load index and speed rating.
- Confirm rim-width range, bolt pattern, hub bore, offset and fasteners.
- Inspect wheel-arch, suspension and brake clearance under real vehicle load.
- Check TPMS, cold pressure and local roadworthiness rules.
- Diameter
- 31.00 in 33.00 in+2.00 in
- Sidewall
- 8.00 in 9.00 in+1.00 in
- Width
- 10.50 in 12.50 in+2.00 in
- Circumference
- 97.39 in 103.67 in+6.5%
- Revs / mile
- 651 611
- Speedo @ 60
- 60 mph 63.9 mph+6.5%
- Ride-height change
- 0.00 in +1.00 in
- True distance per 100 indicated
- 100 mi 106.5 mi+6.5%
- Current —
31x10.50 R15 - New —
33x12.50 R15 - Grounded to the road: the axle rises +1.00 in.
Result report
31x10.50 R15 33x12.50 R15 · Not recommended · Out of tolerance
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Geometric estimate. Always verify physical clearance (arches, suspension, brakes) before fitting.
In-tolerance alternative sizes
| Size | Diameter | Speedo @ 100 | Use this |
|---|---|---|---|
OE 255/80R15 | +0.2% | +0.2% |
31x10.50 R15 · 33x12.50 R15 · Methodology
- Technical check
- 2026-06-28
What changed
- Checked generated routes, metadata, sitemap inclusion and localized page rendering.