What size tyres does the BMW iX take?

It runs 255/50 R21. The exact fitment for your car is on The driver's door jamb, on the lower B-pillar.

Can I fit a cheaper tyre to a BMW iX?

Only at 255/50 R21 109H XL or better. That is the figure to hold: a tyre below the load index, the speed rating or the construction class is not a cheaper one, it is the wrong one.

What pressure should a BMW iX run?

38 psi cold on the fitment above, from the placard. Check it monthly and check it cold, because a warm tyre reads high and an underinflated one costs range every mile you drive.

Do I need the ★ marking?

Not legally. The ★ version can carry a different compound or an acoustic foam liner that the same tread pattern in the shops does not, so if the car is quiet now and you fit the unmarked version, expect to notice.

BMW iX tyres

The BMW iX runs one fitment, 255/50 R21 109H XL. XL is not optional here; it is what the car was type approved on.

Every fitment

Generation	Trim	Wheel	Tyre size	Load index	Speed	Construction	Marking	Pressure
2021 onwards	xDrive50	21in	255/50 R21	109	H	XL	★	38 psi

What you are looking for, drawn. The real one is on the driver's door jamb, on the lower b-pillar, and its figures are the ones that count.

Your own placard is the authority. You will find it on the the driver's door jamb, on the lower B-pillar. Where it disagrees with this page, it wins. Match or exceed the size, load index, speed rating and construction class it gives, and use its pressure figure rather than anything printed on the tyre.

What changes on this car

An H rating on a car this quick surprises people. It is what BMW type approved the 21 inch fitment on, and it is the figure a replacement has to meet rather than beat.

Load index 109 is 1030 kilos a corner. The iX is one of the heaviest things on this site and the load figure is the one to check first, ahead of anything on the label.

A 21 inch wheel costs range, ride and tyre choice all at once. There is a 20 inch option and it is the more sensible car.

No tyres listed against this fitment yet. Product specifications are published from each manufacturer's own data and that work is not finished for 255/50 R21. Match or exceed every figure in the table above and you cannot go far wrong.

Where these figures come from

Michelin's own vehicle fitment tool, michelinman.com/auto/browse-tires/by-vehicle (2025 iX xDrive50 with Sport package, 255/50R21 XL 109H) checked 30 September 2026
Michelin's BMW iX model index across the 2025 and 2026 years checked 30 September 2026

Every figure here comes from one tyre maker's own fitment data, checked across different years or trims. That is a second look rather than a second opinion, so check the label on your door jamb before you buy.

Spotted something wrong? A correction to a fitment is the most useful thing you can send us and it goes to the front of the queue. Tell us.

Fit tyres for a living? Trade accounts get volume pricing on every tyre we list. Open an account.

Common questions

What size tyres does the BMW iX take?: It runs 255/50 R21. The exact fitment for your car is on The driver's door jamb, on the lower B-pillar.
Can I fit a cheaper tyre to a BMW iX?: Only at 255/50 R21 109H XL or better. That is the figure to hold: a tyre below the load index, the speed rating or the construction class is not a cheaper one, it is the wrong one.
What pressure should a BMW iX run?: 38 psi cold on the fitment above, from the placard. Check it monthly and check it cold, because a warm tyre reads high and an underinflated one costs range every mile you drive.
Do I need the ★ marking?: Not legally. The ★ version can carry a different compound or an acoustic foam liner that the same tread pattern in the shops does not, so if the car is quiet now and you fit the unmarked version, expect to notice.