245/35 R20 vs 255/40 R19

255/40 R19 stays within the configured tolerance for 245/35 R20: +1.0% diameter and +1.0% speedometer effect.

Geometric comparison

255/40 R19 stays within the configured tolerance for 245/35 R20: +1.0% diameter and +1.0% speedometer effect.

Geometric comparison
Metric	This size: 245/35 R20	Alternative: 255/40 R19	Difference	Verdict
Overall diameter	26.75 in	27.03 in	+1.0%	Within tolerance
Section width	9.65 in	10.04 in	+0.39 in	Computed difference
Sidewall height	3.38 in	4.02 in	+0.64 in	Computed difference
Circumference	84.04 in	84.92 in	+1.0%	Within tolerance
Speedo	0.0%	+1.0%	+1.0%	Within tolerance

Compare sizes

Current tireLooks valid

New tireLooks valid

Market

Units

Requires verificationWithin tolerance · Diameter +1.0% (+0.28 in) · US (~3%)

Requires verification · This rating covers tire geometry only, not vehicle compatibility.
Diameter +1.0% · Ride-height change +0.14 in.
Speedometer reads low · 60 mph → 60.6 mph.
Sidewall +0.64 in · Width +0.39 in.

Diameter+1.0%+0.28 in

Speedo @ 60+1.0%60 mph → 60.6 mph

Sidewall+0.64 inWidth +0.39 in

Ride-height change+0.14 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: 26.75 in 27.03 in+0.28 in
Sidewall: 3.38 in 4.02 in+0.64 in
Width: 9.65 in 10.04 in+0.39 in
Circumference: 84.04 in 84.92 in+1.0%
Revs / mile: 754 746
Speedo @ 60: 60 mph 60.6 mph+1.0%
Ride-height change: 0.00 in +0.14 in
True distance per 100 indicated: 100 mi 101.0 mi+1.0%

Current — 245/35 R20
New — 255/40 R19
Grounded to the road: the axle rises +0.14 in.

Result report

245/35 R20 255/40 R19 · Requires verification · Within tolerance

Plan budget for this size: 255/40 R19

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Plan budget for this size

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Markdown link

[245/35 R20 vs 255/40 R19 Tire size comparison](https://tirefitlab.com/tire-size-calculator/?from=245%2F35+R20&to=255%2F40+R19&market=us)

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Budget$125–$175Per tire Mid-range$160–$230Per tire Premium$230–$325Per tire

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

In-tolerance alternative sizes

In-tolerance alternative sizes
Size	Diameter	Speedo @ 100
−1″ `245/40R19`	-0.1%	-0.1%
OE `245/35R20`	+0.0%	+0.0%
+1″ `245/30R21`	+0.1%	+0.1%

245/35 R20 · 255/40 R19 · Methodology

Technical check: 2026-06-28

What changed

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

Methodology