285/50 R20 vs 265/70 R17

265/70 R17 stays within the configured tolerance for 285/50 R20: +1.2% diameter and +1.2% speedometer effect.

Geometric comparison

265/70 R17 stays within the configured tolerance for 285/50 R20: +1.2% diameter and +1.2% speedometer effect.

Geometric comparison
Metric	This size: 285/50 R20	Alternative: 265/70 R17	Difference	Verdict
Overall diameter	31.22 in	31.61 in	+1.2%	Within tolerance
Section width	11.22 in	10.43 in	-0.79 in	Computed difference
Sidewall height	5.61 in	7.30 in	+1.69 in	Computed difference
Circumference	98.08 in	99.29 in	+1.2%	Within tolerance
Speedo	0.0%	+1.2%	+1.2%	Within tolerance

Compare sizes

Current tireLooks valid

New tireLooks valid

Market

Units

Not recommendedWithin tolerance · Diameter +1.2% (+0.39 in) · US (~3%)

Not recommended · This rating covers tire geometry only, not vehicle compatibility.
Diameter +1.2% · Ride-height change +0.19 in.
Speedometer reads low · 60 mph → 60.7 mph.
Sidewall +1.69 in · Width -0.79 in.

Diameter+1.2%+0.39 in

Speedo @ 60+1.2%60 mph → 60.7 mph

Sidewall+1.69 inWidth -0.79 in

Ride-height change+0.19 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: 31.22 in 31.61 in+0.39 in
Sidewall: 5.61 in 7.30 in+1.69 in
Width: 11.22 in 10.43 in-0.79 in
Circumference: 98.08 in 99.29 in+1.2%
Revs / mile: 646 638
Speedo @ 60: 60 mph 60.7 mph+1.2%
Ride-height change: 0.00 in +0.19 in
True distance per 100 indicated: 100 mi 101.2 mi+1.2%

Current — 285/50 R20
New — 265/70 R17
Grounded to the road: the axle rises +0.19 in.

Result report

285/50 R20 265/70 R17 · Not recommended · Within tolerance

Copy/print uses this page state only; TireFitLab does not create an account or store a server-side report.

Embed or cite this result

HTML iframe

<iframe src="https://tirefitlab.com/embed/tire-comparison/?from=285%2F50+R20&to=265%2F70+R17&market=us" title="285/50 R20 vs 265/70 R17 Tire size comparison" loading="lazy" width="720" height="330" style="width:100%;max-width:720px;border:0" referrerpolicy="strict-origin-when-cross-origin"></iframe>

Markdown link

[285/50 R20 vs 265/70 R17 Tire size comparison](https://tirefitlab.com/tire-size-calculator/?from=285%2F50+R20&to=265%2F70+R17&market=us)

Open embed preview

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

In-tolerance alternative sizes

In-tolerance alternative sizes
Size	Diameter	Speedo @ 100	Use this
OE `285/50R20`	+0.0%	+0.0%

285/50 R20 · 265/70 R17 · Methodology

Technical check: 2026-06-28

What changed

Checked generated routes, metadata, sitemap inclusion and localized page rendering.

Methodology