TireFitLab

265/70 R17 vs 33x12.50 R18

265/70 R17 vs 33x12.50 R18

33x12.50 R18 is outside the configured tolerance for 265/70 R17: +4.4% diameter and +4.4% speedometer effect.

Fitment verdict

33x12.50 R18 is outside the configured tolerance for 265/70 R17: +4.4% diameter and +4.4% speedometer effect.

Metric This size: 265/70 R17 Alternative: 33x12.50 R18 Difference Verdict
Overall diameter 31.61 in 33.00 in +4.4% Too tall
Section width 10.43 in 12.50 in +2.07 in Computed difference
Sidewall height 7.30 in 7.50 in +0.20 in Computed difference
Circumference 99.29 in 103.67 in +4.4% Too tall
Speedo 0.0% +4.4% +4.4% Outside tolerance

Compare sizes

Looks valid
Looks valid
Units
✕ Out of toleranceDiameter +4.4% (+1.39 in) · US (~3%)
  • Out of tolerance · Diameter +4.4%.
  • Speedo @ 60: 60 mph → 62.6 mph.
  • Sidewall +0.20 in · Width +2.07 in.
Diameter+4.4%+1.39 in
Speedo @ 60+4.4%60 mph → 62.6 mph
Sidewall+0.20 inWidth +2.07 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
31.61 in 33.00 in+1.39 in
Sidewall
7.30 in 7.50 in+0.20 in
Width
10.43 in 12.50 in+2.07 in
Circumference
99.29 in 103.67 in+4.4%
Revs / mile
638 611
Speedo @ 60
60 mph 62.6 mph+4.4%
Δ⌀ +35.4 mm
  • Current — 265/70 R17
  • New — 33x12.50 R18
  • Grounded to the road: the axle rises +0.70 in.

Result report

265/70 R17 33x12.50 R18 · Out of tolerance

Use this size when shopping: 33x12.50 R18

Use this size when shopping

Geometric estimate. Always verify physical clearance (arches, suspension, brakes) before fitting.

Safe alternative sizes

SizeDiameterSpeedo @ 100Use this
−1″ 305/65R16+0.0%+0.0%
OE 265/70R17+0.0%+0.0%
+1″ 345/50R18-0.1%-0.1%
+2″ 355/45R19-0.1%-0.1%

265/70 R17 · 33x12.50 R18 · Methodology

Last reviewed: 2026-06-28
What changed
  • Reviewed deterministic geometry, load/speed references, sitemap inclusion and localized page shell.