33x12.50 R15 vs 275/70 R18

33x12.50 R15 vs 275/70 R18

275/70 R18 stays within the configured tolerance for 33x12.50 R15: +0.5% diameter and +0.5% speedometer effect.

Fitment verdict

275/70 R18 stays within the configured tolerance for 33x12.50 R15: +0.5% diameter and +0.5% speedometer effect.

Metric This size: 33x12.50 R15 Alternative: 275/70 R18 Difference Verdict
Overall diameter 33.00 in 33.16 in +0.5% Within tolerance
Section width 12.50 in 10.83 in -1.67 in Computed difference
Sidewall height 9.00 in 7.58 in -1.42 in Computed difference
Circumference 103.67 in 104.17 in +0.5% Within tolerance
Speedo 0.0% +0.5% +0.5% Within tolerance

Compare sizes

Looks valid
Looks valid
Units
✓ Within toleranceDiameter +0.5% (+0.16 in) · US (~3%)
  • Within tolerance · Diameter +0.5%.
  • Speedo @ 60: 60 mph60.3 mph.
  • Sidewall -1.42 in · Width -1.67 in.
Diameter+0.5%+0.16 in
Speedo @ 60+0.5%60 mph60.3 mph
Sidewall-1.42 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
33.00 in 33.16 in+0.16 in
Sidewall
9.00 in 7.58 in-1.42 in
Width
12.50 in 10.83 in-1.67 in
Circumference
103.67 in 104.17 in+0.5%
Revs / mile
611 608
Speedo @ 60
60 mph 60.3 mph+0.5%
Δ⌀ +4.0 mm
  • Current33x12.50 R15
  • New275/70 R18
  • Grounded to the road: the axle rises +0.08 in.

Result report

33x12.50 R15 275/70 R18 · Within tolerance

Use this size when shopping: 275/70 R18

Use this size when shopping

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

Safe alternative sizes

SizeDiameterSpeedo @ 100Use this
−1″ 345/70R14+0.0%+0.0%
OE 305/75R15+0.0%+0.0%
+1″ 335/65R16+0.4%+0.4%
+2″ 255/80R17+0.2%+0.2%

33x12.50 R15 · 275/70 R18 · Methodology

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