275/45R21 vs 315/40R21

315/40R21 is 4.0 mm taller than 275/45R21 in overall diameter (+0.5%), 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 100.5 km/h.

Dimensions side by side

	275/45R21	315/40R21
Overall diameter	781 mm (30.7″)	785 mm (30.9″)
Section width	275 mm	315 mm
Sidewall height	124 mm	126 mm
Rim	21″	21″
Revolutions per km	408	405
In stock	30 tires from $216.00	19 tires from $319.00

What changes

Overall diameter: 315/40R21 is 4.0 mm taller (+0.5%).
Speedometer: reads 100 km/h at an actual 100.5 km/h with 315/40R21.
315/40R21 is 40 mm wider, so check clearance and the recommended rim width.
Choose a load index at least as high as the one on your door placard.

Vehicles that came with both sizes

Vehicles that use 275/45R21

Vehicles that use 315/40R21

See every alternate size for 275/45R21

Frequently asked questions

Can I use 315/40R21 instead of 275/45R21?

Usually, yes: 315/40R21 is within 3% of the overall diameter of 275/45R21 (+0.5%). 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 275/45R21 and 315/40R21?

With 315/40R21 instead of 275/45R21, the speedometer shows 100 km/h when you are actually doing 100.5 km/h.

Which vehicles came with both 275/45R21 and 315/40R21?

Both sizes were original equipment, on different trims or packages, on the 2020–2024 Mercedes-Benz GLE350, 2017–2024 Mercedes-Benz GLE 63 S, 2020–2024 Mercedes-Benz GLE 53, 2020–2024 Mercedes-Benz GLE63, 2020–2024 Mercedes-Benz GLE450, 2021–2024 Mercedes-Benz GLE53.