TireFitLab

275/65 R18 vs 35x12.50 R18

275/65 R18 vs 35x12.50 R18

35x12.50 R18 is outside the configured tolerance for 275/65 R18: +9.1% diameter and +9.1% speedometer effect.

Fitment verdict

35x12.50 R18 is outside the configured tolerance for 275/65 R18: +9.1% diameter and +9.1% speedometer effect.

Metric This size: 275/65 R18 Alternative: 35x12.50 R18 Difference Verdict
Overall diameter 32.07 in 35.00 in +9.1% Too tall
Section width 10.83 in 12.50 in +1.67 in Computed difference
Sidewall height 7.04 in 8.50 in +1.46 in Computed difference
Circumference 100.77 in 109.96 in +9.1% Too tall
Speedo 0.0% +9.1% +9.1% Outside tolerance

Compare sizes

Looks valid
Looks valid
Units
✕ Out of toleranceDiameter +9.1% (+2.93 in) · US (~3%)
  • Out of tolerance · Diameter +9.1%.
  • Speedo @ 60: 60 mph → 65.5 mph.
  • Sidewall +1.46 in · Width +1.67 in.
Diameter+9.1%+2.93 in
Speedo @ 60+9.1%60 mph → 65.5 mph
Sidewall+1.46 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
32.07 in 35.00 in+2.93 in
Sidewall
7.04 in 8.50 in+1.46 in
Width
10.83 in 12.50 in+1.67 in
Circumference
100.77 in 109.96 in+9.1%
Revs / mile
629 576
Speedo @ 60
60 mph 65.5 mph+9.1%
Δ⌀ +74.3 mm
  • Current — 275/65 R18
  • New — 35x12.50 R18
  • Grounded to the road: the axle rises +1.46 in.

Result report

275/65 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″ 255/75R17-0.0%-0.0%
OE 275/65R18+0.0%+0.0%
+1″ 255/65R19-0.1%-0.1%
+2″ 255/60R20-0.1%-0.1%

275/65 R18 · 35x12.50 R18 · Methodology

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