265/45 R20

What size is 265/45 R20?

265/45 R20 has an overall diameter of about 29.39 in, a section width of 10.43 in and a sidewall height of 4.69 in. It turns roughly 686 times per mile. Below are the exact figures plus in-tolerance plus/minus sizes you can switch to safely.

Fitment verdict

265/50 R19 stays within the configured tolerance for 265/45 R20: +0.1% diameter and +0.1% speedometer effect.

Metric This size: 265/45 R20 Alternative: 265/50 R19 Difference Verdict
Overall diameter 29.39 in 29.43 in +0.1% Within tolerance
Section width 10.43 in 10.43 in 0.00 in Computed difference
Sidewall height 4.69 in 5.22 in +0.52 in Computed difference
Circumference 92.33 in 92.47 in +0.1% Within tolerance
Speedo 0.0% +0.1% +0.1% Within tolerance

Seasonal check

Planning a long summer drive?

Use the budget and running-cost tools before a trip, especially if the current tyres are worn or the replacement size changes diameter.

Estimate tyre budget

Specification

Overall diameter29.39 in
Section width10.43 in
Sidewall height4.69 in
Circumference92.33 in
Revolutions 426 /km · 686 /mi

In-tolerance sizes

Alternative sizes that stay within the safe diameter tolerance:

Size Diameter Speedo Verdict
265/50 R19 +0.1% +0.1% ✓ OK
295/40 R20 -0.3% -0.3% ✓ OK
245/70 R16 +0.4% +0.4% ✓ OK
245/65 R17 +0.5% +0.5% ✓ OK
245/60 R18 +0.6% +0.6% ✓ OK
235/55 R19 -0.7% -0.7% ✓ OK
305/40 R20 +0.7% +0.7% ✓ OK
295/35 R21 -0.9% -0.9% ✓ OK
235/60 R18 -1.0% -1.0% ✓ OK
285/45 R19 -1.0% -1.0% ✓ OK
255/55 R18 -1.2% -1.2% ✓ OK
255/50 R19 -1.2% -1.2% ✓ OK

Compare sizes

Looks valid
Looks valid
Units
✓ Within toleranceDiameter +0.1% (+0.04 in) · US (~3%)
  • Within tolerance · Diameter +0.1%.
  • Speedo @ 60: 60 mph60.1 mph.
  • Sidewall +0.52 in · Width +0.00 in.
Diameter+0.1%+0.04 in
Speedo @ 60+0.1%60 mph60.1 mph
Sidewall+0.52 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
29.39 in 29.43 in+0.04 in
Sidewall
4.69 in 5.22 in+0.52 in
Width
10.43 in 10.43 in+0.00 in
Circumference
92.33 in 92.47 in+0.1%
Revs / mile
686 685
Speedo @ 60
60 mph 60.1 mph+0.1%
Δ⌀ +1.1 mm
  • Current265/45 R20
  • New265/50 R19
  • Grounded to the road: the axle rises +0.02 in.

Result report

265/45 R20 265/50 R19 · Within tolerance

Use this size when shopping: 265/50 R19

Use this size when shopping

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

Safe alternative sizes

SizeDiameterSpeedo @ 100Use this
−1″ 165/80R19+0.0%+0.0%
OE 265/45R20+0.0%+0.0%
+1″ 355/30R21-0.0%-0.0%
+2″ 125/75R22-0.0%-0.0%

More tools

Last reviewed: 2026-06-28

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