275/40 R20 vs 275/45 R19

275/40 R20 vs 275/45 R19

275/45 R19 stays within the configured tolerance for 275/40 R20: +0.3% diameter and +0.3% speedometer effect.

Fitment verdict

275/45 R19 stays within the configured tolerance for 275/40 R20: +0.3% diameter and +0.3% speedometer effect.

Metric This size: 275/40 R20 Alternative: 275/45 R19 Difference Verdict
Overall diameter 28.66 in 28.74 in +0.3% Within tolerance
Section width 10.83 in 10.83 in 0.00 in Computed difference
Sidewall height 4.33 in 4.87 in +0.54 in Computed difference
Circumference 90.04 in 90.30 in +0.3% Within tolerance
Speedo 0.0% +0.3% +0.3% Within tolerance

Compare sizes

Looks valid
Looks valid
Units
✓ Within toleranceDiameter +0.3% (+0.08 in) · US (~3%)
  • Within tolerance · Diameter +0.3%.
  • Speedo @ 60: 60 mph60.2 mph.
  • Sidewall +0.54 in · Width +0.00 in.
Diameter+0.3%+0.08 in
Speedo @ 60+0.3%60 mph60.2 mph
Sidewall+0.54 inWidth +0.00 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 28.74 in+0.08 in
Sidewall
4.33 in 4.87 in+0.54 in
Width
10.83 in 10.83 in+0.00 in
Circumference
90.04 in 90.30 in+0.3%
Revs / mile
704 702
Speedo @ 60
60 mph 60.2 mph+0.3%
Δ⌀ +2.1 mm
  • Current275/40 R20
  • New275/45 R19
  • Grounded to the road: the axle rises +0.04 in.

Result report

275/40 R20 275/45 R19 · Within tolerance

Use this size when shopping: 275/45 R19

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 · 275/45 R19 · Methodology

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