2021 BMW X7 tire size

Most common factory size

P285/45R21

Tire sizes by trim

Source marks: one source

2021 BMW X7 tire size by trim
Size	Trims	Width, mm	Sidewall, % of width	Rim, in	Diameter, in	Sidewall, in	Revs per mile
P285/45R21	xDrive40i AWD, M50i AWD, ALPINA XB7 AWD	285	45	21	31.10	5.05	649
P275/45R22	M50i Dark Shadow Edition AWD	275	45	22	31.74	4.87	635

What P285/45R21 means
Part	Number	Meaning
Type	P	Passenger car tire.
Width	285 mm	Tread width. 11.2 in.
Sidewall	45	Sidewall height is 45% of the width.
Construction	R	Radial tire.
Rim	21 in	Fits 21 in wheels.

Within 3% of the stock diameter. A common shop guideline, not a maker spec.

Sizes within 3% of P285/45R21
Size	Rim, in	Diameter, in	Change	Speedo reads at 60 mph
235/60R20	20	31.10	+0.0%	60.0 mph
255/55R20	20	31.04	-0.2%	60.1 mph
255/50R21	21	31.04	-0.2%	60.1 mph
255/45R22	22	31.04	-0.2%	60.1 mph
285/40R22	22	30.98	-0.4%	60.2 mph
285/50R20	20	31.22	+0.4%	59.8 mph
295/40R22	22	31.29	+0.6%	59.6 mph
275/50R20	20	30.83	-0.9%	60.5 mph

Sizes within 3% of P275/45R22
Size	Rim, in	Diameter, in	Change	Speedo reads at 60 mph
275/50R21	21	31.83	+0.3%	59.8 mph
285/40R23	23	31.98	+0.7%	59.6 mph
285/45R22	22	32.10	+1.1%	59.3 mph
295/40R22	22	31.29	-1.4%	60.9 mph
285/45R21	21	31.10	-2.0%	61.2 mph
265/50R22	22	32.43	+2.2%	58.7 mph
255/50R21	21	31.04	-2.2%	61.4 mph
255/45R22	22	31.04	-2.2%	61.4 mph

Checked against 292 factory sizes listed for 2009-2027 US models.

Tire pressure is on the driver door sticker. Not in this data.

Optional wheel packages may differ.