TireFitLab

245/70 R16 vs 33x12.50 R18

245/70 R16 vs 33x12.50 R18

33x12.50 R18 is outside the configured tolerance for 245/70 R16: +11.8% diameter and +11.8% speedometer effect.

Fitment verdict

33x12.50 R18 is outside the configured tolerance for 245/70 R16: +11.8% diameter and +11.8% speedometer effect.

Metric This size: 245/70 R16 Alternative: 33x12.50 R18 Difference Verdict
Overall diameter 29.50 in 33.00 in +11.8% Too tall
Section width 9.65 in 12.50 in +2.85 in Computed difference
Sidewall height 6.75 in 7.50 in +0.75 in Computed difference
Circumference 92.69 in 103.67 in +11.8% Too tall
Speedo 0.0% +11.8% +11.8% Outside tolerance

Compare sizes

Looks valid
Looks valid
Units
✕ Out of toleranceDiameter +11.8% (+3.50 in) · US (~3%)
  • Out of tolerance · Diameter +11.8%.
  • Speedo @ 60: 60 mph → 67.1 mph.
  • Sidewall +0.75 in · Width +2.85 in.
Diameter+11.8%+3.50 in
Speedo @ 60+11.8%60 mph → 67.1 mph
Sidewall+0.75 inWidth +2.85 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
29.50 in 33.00 in+3.50 in
Sidewall
6.75 in 7.50 in+0.75 in
Width
9.65 in 12.50 in+2.85 in
Circumference
92.69 in 103.67 in+11.8%
Revs / mile
684 611
Speedo @ 60
60 mph 67.1 mph+11.8%
Δ⌀ +88.8 mm
  • Current — 245/70 R16
  • New — 33x12.50 R18
  • Grounded to the road: the axle rises +1.75 in.

Result report

245/70 R16 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″ 335/55R15+0.0%+0.0%
OE 245/70R16+0.0%+0.0%
+1″ 265/60R17+0.1%+0.1%
+2″ 195/75R18+0.0%+0.0%

245/70 R16 · 33x12.50 R18 · Methodology

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