265/60 R18 vs 31x10.50 R15

31x10.50 R15 stays within the configured tolerance for 265/60 R18: +1.6% diameter and +1.6% speedometer effect.

Geometric comparison

31x10.50 R15 stays within the configured tolerance for 265/60 R18: +1.6% diameter and +1.6% speedometer effect.

Geometric comparison
Metric	This size: 265/60 R18	Alternative: 31x10.50 R15	Difference	Verdict
Overall diameter	30.52 in	31.00 in	+1.6%	Within tolerance
Section width	10.43 in	10.50 in	+0.07 in	Computed difference
Sidewall height	6.26 in	8.00 in	+1.74 in	Computed difference
Circumference	95.88 in	97.39 in	+1.6%	Within tolerance
Speedo	0.0%	+1.6%	+1.6%	Within tolerance

Compare sizes

Current tireLooks valid

New tireLooks valid

Market

Units

Not recommendedWithin tolerance · Diameter +1.6% (+0.48 in) · US (~3%)

Not recommended · This rating covers tire geometry only, not vehicle compatibility.
Diameter +1.6% · Ride-height change +0.24 in.
Speedometer reads low · 60 mph → 60.9 mph.
Sidewall +1.74 in · Width +0.07 in.

Diameter+1.6%+0.48 in

Speedo @ 60+1.6%60 mph → 60.9 mph

Sidewall+1.74 inWidth +0.07 in

Ride-height change+0.24 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: 30.52 in 31.00 in+0.48 in
Sidewall: 6.26 in 8.00 in+1.74 in
Width: 10.43 in 10.50 in+0.07 in
Circumference: 95.88 in 97.39 in+1.6%
Revs / mile: 661 651
Speedo @ 60: 60 mph 60.9 mph+1.6%
Ride-height change: 0.00 in +0.24 in
True distance per 100 indicated: 100 mi 101.6 mi+1.6%

Current — 265/60 R18
New — 31x10.50 R15
Grounded to the road: the axle rises +0.24 in.

Result report

265/60 R18 31x10.50 R15 · Not recommended · Within tolerance

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Markdown link

[265/60 R18 vs 31x10.50 R15 Tire size comparison](https://tirefitlab.com/tire-size-calculator/?from=265%2F60+R18&to=31x10.50+R15&market=us)

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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
−1″ `245/70R17`	-0.1%	-0.1%
OE `265/60R18`	+0.0%	+0.0%

265/60 R18 · 31x10.50 R15 · Methodology

Technical check: 2026-06-28

What changed

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

Methodology