275/40R23 vs 285/40R23 tire size comparison

Change either size and everything below updates.

Start from your car make, model, year

Make Model Year

Width/AspectRRim

DiameterxWidthRRim

Width/AspectRRim

DiameterxWidthRRim

Width in mm · aspect = sidewall height as a % of width · rim in inches

Flotation (LT) sizes, all in inches: overall diameter × section width, then rim

Well within tolerance

+0.99% diameter

The overall diameter changes by less than 1.5%, so speedometer error is negligible and ride height barely moves.

10 mm wider: check inner clearance and that your rims are wide enough.

Tires in 285/40R23

Check price on Amazon · 285/40R23 Best-rated 285/40R23 tires

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Measurement	275/40R23	285/40R23	Diff	%
Overall diameter	31.66″804 mm	31.98″812 mm	+0.31″	+1.0%
Section width	275.0 mm	285.0 mm	+10.0 mm	+3.6%
Sidewall height	110.0 mm	114.0 mm	+4.0 mm	+3.6%
Rim diameter	23″	23″	0″	0.0%
Circumference	99.47″2526 mm	100.46″2552 mm	+0.99″	+1.0%
Revolutions per mileturns per distance; drives the odometer	637396 /km	631392 /km	−6	−1.0%
Ride height change	—	—	+0.16″ +4.0 mm

Speedometer reading

Speedo shows

60mph

97 km/h

Actual speed

60.6mph

98 km/h

Overlay

275/40R23285/40R23

How to use the tire size calculator

Put your current tire size — width, aspect ratio and rim diameter — into the first form, then your desired size into the second. You’ll get the difference between the new and the old size, plus the speedometer reading difference and your actual speed on the new set. Both metric and flotation (LT inch) sizes are supported.

The calculator helps you decide whether a set of tires and wheels will fit your car. To compare tires by brand and model instead, use our tire comparison tool; to look up factory sizes, browse by car make.