275/40 R20 vs 295/35 R21

275/40 R20 vs 295/35 R21

295/35 R21 stays within the configured tolerance for 275/40 R20: +1.6% diameter and +1.6% speedometer effect.

Fitment verdict

295/35 R21 stays within the configured tolerance for 275/40 R20: +1.6% diameter and +1.6% speedometer effect.

Metric This size: 275/40 R20 Alternative: 295/35 R21 Difference Verdict
Overall diameter 28.66 in 29.13 in +1.6% Within tolerance
Section width 10.83 in 11.61 in +0.79 in Computed difference
Sidewall height 4.33 in 4.06 in -0.27 in Computed difference
Circumference 90.04 in 91.51 in +1.6% Within tolerance
Speedo 0.0% +1.6% +1.6% Within tolerance

Compare sizes

Looks valid
Looks valid
Units
✓ Within toleranceDiameter +1.6% (+0.47 in) · US (~3%)
  • Within tolerance · Diameter +1.6%.
  • Speedo @ 60: 60 mph61.0 mph.
  • Sidewall -0.27 in · Width +0.79 in.
Diameter+1.6%+0.47 in
Speedo @ 60+1.6%60 mph61.0 mph
Sidewall-0.27 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
28.66 in 29.13 in+0.47 in
Sidewall
4.33 in 4.06 in-0.27 in
Width
10.83 in 11.61 in+0.79 in
Circumference
90.04 in 91.51 in+1.6%
Revs / mile
704 692
Speedo @ 60
60 mph 61.0 mph+1.6%
Δ⌀ +11.9 mm
  • Current275/40 R20
  • New295/35 R21
  • Grounded to the road: the axle rises +0.23 in.

Result report

275/40 R20 295/35 R21 · Within tolerance

Use this size when shopping: 295/35 R21

Use this size when shopping

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

Safe alternative sizes

SizeDiameterSpeedo @ 100Use this
−1″ 175/70R19-0.1%-0.1%
OE 275/40R20+0.0%+0.0%
+1″ 195/50R21+0.1%+0.1%
+2″ 155/55R22+0.2%+0.2%

275/40 R20 · 295/35 R21 · Methodology

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