285/40R22 vs 315/40R21

315/40R21 is 2.0 mm shorter than 285/40R22 in overall diameter (−0.3%), within the usual 3% limit, so it can replace it where the wheels and clearance allow. With 315/40R21 fitted, the speedometer reads 100 km/h when you are doing 99.7 km/h.

Dimensions side by side

	285/40R22	315/40R21
Overall diameter	787 mm (31.0″)	785 mm (30.9″)
Section width	285 mm	315 mm
Sidewall height	114 mm	126 mm
Rim	22″	21″
Revolutions per km	404	405
In stock	18 tires from $399.00	19 tires from $319.00

What changes

Overall diameter: 315/40R21 is 2.0 mm shorter (−0.3%).
Speedometer: reads 100 km/h at an actual 99.7 km/h with 315/40R21.
315/40R21 is 30 mm wider, so check clearance and the recommended rim width.
Wheel size changes from 22″ to 21″: you need wheels in the new size.
Choose a load index at least as high as the one on your door placard.

Vehicles that came with both sizes

Vehicles that use 285/40R22

Vehicles that use 315/40R21

See every alternate size for 285/40R22

Frequently asked questions

Can I use 315/40R21 instead of 285/40R22?

Usually, yes: 315/40R21 is within 3% of the overall diameter of 285/40R22 (−0.3%). Use wheels of the right size and width, match or exceed the original load index, and check clearance at full steering lock.

How much does the speedometer change between 285/40R22 and 315/40R21?

With 315/40R21 instead of 285/40R22, the speedometer shows 100 km/h when you are actually doing 99.7 km/h.

Which vehicles came with both 285/40R22 and 315/40R21?

Both sizes were original equipment, on different trims or packages, on the 2017–2024 Mercedes-Benz GLE 63 S, 2019–2024 Lamborghini Urus, 2020–2024 Mercedes-Benz GLE 53, 2020–2024 Mercedes-Benz GLE450, 2021–2024 Mercedes-Benz GLE53, 2020–2024 Mercedes-Benz GLE580.