GENUINE BMW 3 SERIES 403 M SPORT 4 F30 F32 F36 ALLOY WHEEL 7850021 REAR 19x8.5J

Part number 7850021. We take parts off vehicles every week, and this page is updated with a link straight to the part as soon as another one arrives.

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What this part sells for

We last sold a part with this number on 2025-09-12 for GBP 59.00, delivered.

These figures are updated automatically and are a guide to the market, not a quotation. The price of the part we have in stock is on its own page.

About part number 7850021

An alloy wheel forms the outer metal structure that holds the tyre and connects the wheel hub to the road surface. As part of the steering and suspension system, it supports the weight of the vehicle and allows the road wheels to rotate smoothly. When the wheel is in good order and balanced correctly, the driver experiences a steady ride with precise handling and no unusual vibrations through the steering or chassis.

To confirm that this wheel matches your vehicle, you must check the original manufacturer part number on your existing unit. On a wheel of this type, the part number is usually stamped or cast into the inner face or the back of the spokes. You should match part number 7850021 exactly to ensure correct fitment, as the part number alone determines compatibility.

When replacing an alloy wheel, a technician usually fits a fresh tyre, a new air valve or tyre pressure monitoring sensor, and replacement balancing weights. Wheels are typically replaced after suffering heavy impact damage from deep potholes or kerbs, or when severe corrosion prevents a tyre from sealing properly around the rim.

About this kind of part: alloy wheels

An alloy wheel is a cast or forged aluminium wheel. Four numbers describe it and all four have to match the car: the diameter in inches, the rim width in inches followed by the letter J, the number of bolt holes with the circle they sit on in millimetres, and the offset, marked ET, which is how far the mounting face sits from the centre line. A casting number is marked on the back of the spokes or inside the rim, and that number is what identifies the exact wheel rather than one that merely looks the same.

Why people replace one

  • A kerb has taken the paint or the lacquer off the outer rim, which is cosmetic but shows from across the road.
  • A pothole has put a flat spot or a bend in the rim, which makes the steering shake at speed and will not balance out.
  • The lacquer has lifted and the aluminium underneath has gone white and powdery, which spreads once it starts.
  • One wheel of a set has been lost or damaged beyond use, and a matching single is needed rather than a new set of four.
  • A change of tyre size or a seasonal set means a second set of wheels is wanted.

Fitting it

  • The bolts or nuts must be the correct type for the wheel. A tapered seat and a radius seat are not interchangeable, and the wrong one will work loose.
  • Centre caps and the trim rings around the bolt holes are separate parts and are specific to the model.
  • A wheel fitted to a car with tyre pressure monitoring needs a sensor in the valve, and the sensor may need pairing to the car.
  • Wheel bolts must be tightened to the figure in the handbook, and checked again after a short distance.

Making sure it is the right one

  • Match the casting number from the back of the wheel. Two wheels can share a diameter, a width and a bolt pattern and still be different parts with a different offset.
  • The offset matters as much as the size. A wheel with the wrong ET figure will sit too far in or too far out, and can foul the suspension or the arch.
  • Check the bolt circle exactly. Five bolts on a 108 millimetre circle and five on a 110 millimetre circle look identical and will not both fit.
  • If a tyre is fitted, read its size from the sidewall and check it against the rim width. A tyre size that cannot sit on the rim in front of you means the rim marking has been misread.

What to look for in the photographs

A Casting number — Raised or stamped on the back of the spokes or inside the barrel. A wheel often carries several numbers in several places, and this is the one that identifies the part.
B Size and offset markings — Cast into the back of the wheel as a diameter, a width with the letter J, and an ET figure. All three have to match your car.
C Outer rim edge — Where kerb damage shows first. Look along the whole circumference, not just the part facing the camera.
D Bolt holes and seats — The seats the bolts tighten against. Check the shape of the seat as well as the number of holes.
E Centre bore and cap seat — The large central opening and the lip the centre cap clips into. The cap is a separate part.
F Face finish — Painted, machined, diamond-cut or polished. A diamond-cut face cannot be touched in without re-cutting, so the finish is part of what you are matching.

This section describes alloy wheels parts in general. The numbers and the photographs above are this part.

Free next-day delivery in the United Kingdom Sent with DPD on a tracked, next-day service. Most mainland addresses are next day; the Highlands and Islands, Northern Ireland, the Channel Islands and the Isle of Man can take a day longer.

Returns Thirty days to change your mind, and we pay the return postage in the United Kingdom and Germany.

Trade and VAT C.E.J Haime Group Limited is VAT registered in England and Wales, and every order comes with a full VAT invoice.

Not sure it is the right part? Send us your registration or VIN and we will check this part number against your own vehicle before you buy.

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