TireFitLab

295/40 R20

What size is 295/40 R20?

295/40 R20 has an overall diameter of about 29.29 in, a section width of 11.61 in and a sidewall height of 4.65 in. It turns roughly 689 times per mile. Below are the exact figures plus plus/minus sizes that stay within the selected diameter tolerance.

Geometric comparison

265/45 R20 stays within the configured tolerance for 295/40 R20: +0.3% diameter and +0.3% speedometer effect.

Geometric comparison
Metric This size: 295/40 R20 Alternative: 265/45 R20 Difference Verdict
Overall diameter 29.29 in 29.39 in +0.3% Within tolerance
Section width 11.61 in 10.43 in -1.18 in Computed difference
Sidewall height 4.65 in 4.69 in +0.05 in Computed difference
Circumference 92.02 in 92.33 in +0.3% Within tolerance
Speedo 0.0% +0.3% +0.3% Within tolerance

Seasonal check

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What this geometry means

295/40 R20 has a low-profile proportion. The marking combines nominal section width 11.61 in, sidewall ratio 40% and rim diameter 20 inches. One sidewall is 4.65 in; both sidewalls make up 32% of the 29.29 in overall diameter, while the rim makes up 68%.

The closest diameter entry is 265/45 R20 at +0.3%. Relative to 295/40 R20, it changes nominal section width by -1.18 in, each sidewall by +0.05 in and radius by +0.05 in.

At the nominal 92.02 in circumference, 1,000 rotations cover 2.34 km (1.45 mi); the inverse rates are 428/km and 689/mi.

Width endpoints in that set are 235/55 R19 (-2.36 in) and 295/35 R21 (+0.00 in) relative to 295/40 R20.

Curated alternatives: 12 sizes, spanning -0.9% to +0.8% in nominal diameter versus 295/40 R20.

Section-width mix versus 295/40 R20: 11 narrower, 1 equal-width and 0 wider entries.

This is a nominal geometry comparison only. Vehicle clearance, wheel width and offset, load and speed ratings, and manufacturer approval still require separate checks.

Specification

Specification
Overall diameter 29.29 in
Section width 11.61 in
Sidewall height 4.65 in
Circumference 92.02 in
Revolutions 428 /km · 689 /mi

In-tolerance sizes

Alternative sizes that stay within the selected diameter tolerance:

In-tolerance sizes
Size Diameter Speedo Verdict
265/45 R20 +0.3% +0.3% ✓ OK
235/55 R19 -0.4% -0.4% ✓ OK
265/50 R19 +0.5% +0.5% ✓ OK
295/35 R21 -0.6% -0.6% ✓ OK
235/60 R18 -0.6% -0.6% ✓ OK
285/45 R19 -0.7% -0.7% ✓ OK
245/70 R16 +0.7% +0.7% ✓ OK
245/65 R17 +0.8% +0.8% ✓ OK
255/55 R18 -0.8% -0.8% ✓ OK
255/50 R19 -0.9% -0.9% ✓ OK
255/45 R20 -0.9% -0.9% ✓ OK
235/65 R17 -0.9% -0.9% ✓ OK

Compare sizes

Looks valid
Looks valid
Units
Requires verificationWithin tolerance · Diameter +0.3% (+0.10 in) · US (~3%)
  • Requires verification · This rating covers tire geometry only, not vehicle compatibility.
  • Diameter +0.3% · Ride-height change +0.05 in.
  • Speedometer reads low · 60 mph → 60.2 mph.
  • Sidewall +0.05 in · Width -1.18 in.
Diameter+0.3%+0.10 in
Speedo @ 60+0.3%60 mph → 60.2 mph
Sidewall+0.05 inWidth -1.18 in
Ride-height change+0.05 inDiameter ÷ 2
How this result is calculated

Computed from nominal tire-size geometry: diameter, circumference and speedometer error. It does not check vehicle placard approval, load/speed rating, rim-width range, wheel-arch, suspension or brake clearance.

Methodology

Before fitting

  • Check the vehicle placard and owner’s manual first.
  • Match or exceed the required load index and speed rating.
  • Confirm rim-width range, bolt pattern, hub bore, offset and fasteners.
  • Inspect wheel-arch, suspension and brake clearance under real vehicle load.
  • Check TPMS, cold pressure and local roadworthiness rules.
Diameter
29.29 in 29.39 in+0.10 in
Sidewall
4.65 in 4.69 in+0.05 in
Width
11.61 in 10.43 in-1.18 in
Circumference
92.02 in 92.33 in+0.3%
Revs / mile
689 686
Speedo @ 60
60 mph 60.2 mph+0.3%
Ride-height change
0.00 in +0.05 in
True distance per 100 indicated
100 mi 100.3 mi+0.3%
Δ⌀ +0.10 inΔ↔ -1.18 in
  • Current — 295/40 R20
  • New — 265/45 R20
  • Grounded to the road: the axle rises +0.05 in.

Result report

295/40 R20 265/45 R20 · Requires verification · Within tolerance

Plan budget for this size: 265/45 R20

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Plan budget for this size
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Budget$150–$210Per tireMid-range$195–$280Per tirePremium$280–$395Per tire

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

In-tolerance alternative sizes

In-tolerance alternative sizes
SizeDiameterSpeedo @ 100Use this
OE 295/40R20+0.0%+0.0%

More tools

Last reviewed: 2026-07-22

Technical check
2026-07-22
Content updated
2026-07-22
What changed
  • Added a localized engine-derived geometry signature and matching Markdown narrative.
Methodology