285/60 R18 vs 265/70 R17

285/60 R18 vs 265/70 R17

265/70 R17 stays within the configured tolerance for 285/60 R18: +0.5% diameter and +0.5% speedometer effect.

Fitment verdict

265/70 R17 stays within the configured tolerance for 285/60 R18: +0.5% diameter and +0.5% speedometer effect.

Metric This size: 285/60 R18 Alternative: 265/70 R17 Difference Verdict
Overall diameter 31.46 in 31.61 in +0.5% Within tolerance
Section width 11.22 in 10.43 in -0.79 in Computed difference
Sidewall height 6.73 in 7.30 in +0.57 in Computed difference
Circumference 98.85 in 99.29 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% (+0.14 in) · US (~3%)
  • Within tolerance · Diameter +0.5%.
  • Speedo @ 60: 60 mph60.3 mph.
  • Sidewall +0.57 in · Width -0.79 in.
Diameter+0.5%+0.14 in
Speedo @ 60+0.5%60 mph60.3 mph
Sidewall+0.57 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
31.46 in 31.61 in+0.14 in
Sidewall
6.73 in 7.30 in+0.57 in
Width
11.22 in 10.43 in-0.79 in
Circumference
98.85 in 99.29 in+0.5%
Revs / mile
641 638
Speedo @ 60
60 mph 60.3 mph+0.5%
Δ⌀ +3.6 mm
  • Current285/60 R18
  • New265/70 R17
  • Grounded to the road: the axle rises +0.07 in.

Result report

285/60 R18 265/70 R17 · Within tolerance

Use this size when shopping: 265/70 R17

Use this size when shopping

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

Safe alternative sizes

SizeDiameterSpeedo @ 100Use this
−1″ 245/75R17+0.0%+0.0%
OE 285/60R18+0.0%+0.0%
+1″ 265/60R19+0.2%+0.2%
+2″ 265/55R20+0.0%+0.0%

285/60 R18 · 265/70 R17 · Methodology

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