TireFitLab

275/70 R18 vs 35x12.50 R18

275/70 R18 vs 35x12.50 R18

35x12.50 R18 is outside the configured tolerance for 275/70 R18: +5.6% diameter and +5.6% speedometer effect.

Fitment verdict

35x12.50 R18 is outside the configured tolerance for 275/70 R18: +5.6% diameter and +5.6% speedometer effect.

Metric This size: 275/70 R18 Alternative: 35x12.50 R18 Difference Verdict
Overall diameter 33.16 in 35.00 in +5.6% Too tall
Section width 10.83 in 12.50 in +1.67 in Computed difference
Sidewall height 7.58 in 8.50 in +0.92 in Computed difference
Circumference 104.17 in 109.96 in +5.6% Too tall
Speedo 0.0% +5.6% +5.6% Outside tolerance

Compare sizes

Looks valid
Looks valid
Units
✕ Out of toleranceDiameter +5.6% (+1.84 in) · US (~3%)
  • Out of tolerance · Diameter +5.6%.
  • Speedo @ 60: 60 mph → 63.3 mph.
  • Sidewall +0.92 in · Width +1.67 in.
Diameter+5.6%+1.84 in
Speedo @ 60+5.6%60 mph → 63.3 mph
Sidewall+0.92 inWidth +1.67 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
33.16 in 35.00 in+1.84 in
Sidewall
7.58 in 8.50 in+0.92 in
Width
10.83 in 12.50 in+1.67 in
Circumference
104.17 in 109.96 in+5.6%
Revs / mile
608 576
Speedo @ 60
60 mph 63.3 mph+5.6%
Δ⌀ +46.8 mm
  • Current — 275/70 R18
  • New — 35x12.50 R18
  • Grounded to the road: the axle rises +0.92 in.

Result report

275/70 R18 35x12.50 R18 · Out of tolerance

Use this size when shopping: 35x12.50 R18

Use this size when shopping

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

Safe alternative sizes

SizeDiameterSpeedo @ 100Use this
−1″ 315/65R17-0.1%-0.1%
OE 275/70R18+0.0%+0.0%
+1″ 225/80R19+0.0%+0.0%
+2″ 335/50R20+0.1%+0.1%

275/70 R18 · 35x12.50 R18 · Methodology

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