265/70 R17 vs 275/55 R20

265/70 R17 vs 275/55 R20

275/55 R20 stays within the configured tolerance for 265/70 R17: +1.0% diameter and +1.0% speedometer effect.

Fitment verdict

275/55 R20 stays within the configured tolerance for 265/70 R17: +1.0% diameter and +1.0% speedometer effect.

Metric This size: 265/70 R17 Alternative: 275/55 R20 Difference Verdict
Overall diameter 31.61 in 31.91 in +1.0% Within tolerance
Section width 10.43 in 10.83 in +0.39 in Computed difference
Sidewall height 7.30 in 5.95 in -1.35 in Computed difference
Circumference 99.29 in 100.25 in +1.0% Within tolerance
Speedo 0.0% +1.0% +1.0% Within tolerance

Compare sizes

Looks valid
Looks valid
Units
✓ Within toleranceDiameter +1.0% (+0.30 in) · US (~3%)
  • Within tolerance · Diameter +1.0%.
  • Speedo @ 60: 60 mph60.6 mph.
  • Sidewall -1.35 in · Width +0.39 in.
Diameter+1.0%+0.30 in
Speedo @ 60+1.0%60 mph60.6 mph
Sidewall-1.35 inWidth +0.39 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 31.91 in+0.30 in
Sidewall
7.30 in 5.95 in-1.35 in
Width
10.43 in 10.83 in+0.39 in
Circumference
99.29 in 100.25 in+1.0%
Revs / mile
638 632
Speedo @ 60
60 mph 60.6 mph+1.0%
Δ⌀ +7.7 mm
  • Current265/70 R17
  • New275/55 R20
  • Grounded to the road: the axle rises +0.15 in.

Result report

265/70 R17 275/55 R20 · Within tolerance

Use this size when shopping: 275/55 R20

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 · 275/55 R20 · Methodology

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