TireFitLab

265/70 R17 vs 285/65 R18

265/70 R17 vs 285/65 R18

285/65 R18 is outside the configured tolerance for 265/70 R17: +3.1% diameter and +3.1% speedometer effect.

Fitment verdict

285/65 R18 is outside the configured tolerance for 265/70 R17: +3.1% diameter and +3.1% speedometer effect.

Metric This size: 265/70 R17 Alternative: 285/65 R18 Difference Verdict
Overall diameter 31.61 in 32.59 in +3.1% Too tall
Section width 10.43 in 11.22 in +0.79 in Computed difference
Sidewall height 7.30 in 7.29 in -0.01 in Computed difference
Circumference 99.29 in 102.37 in +3.1% Too tall
Speedo 0.0% +3.1% +3.1% Outside tolerance

Compare sizes

Looks valid
Looks valid
Units
✕ Out of toleranceDiameter +3.1% (+0.98 in) · US (~3%)
  • Out of tolerance · Diameter +3.1%.
  • Speedo @ 60: 60 mph → 61.9 mph.
  • Sidewall -0.01 in · Width +0.79 in.
Diameter+3.1%+0.98 in
Speedo @ 60+3.1%60 mph → 61.9 mph
Sidewall-0.01 inWidth +0.79 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 32.59 in+0.98 in
Sidewall
7.30 in 7.29 in-0.01 in
Width
10.43 in 11.22 in+0.79 in
Circumference
99.29 in 102.37 in+3.1%
Revs / mile
638 619
Speedo @ 60
60 mph 61.9 mph+3.1%
Δ⌀ +24.9 mm
  • Current — 265/70 R17
  • New — 285/65 R18
  • Grounded to the road: the axle rises +0.49 in.

Result report

265/70 R17 285/65 R18 · Out of tolerance

Use this size when shopping: 285/65 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 · 285/65 R18 · Methodology

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