This part is listed by BMW as BMW part number 33008328143 (33 00 8 328 143) and is a larger and thicker rear wheel hub flange that can be used to upgrade the factory original hub for endurance racing (it replaces the original factory part #33402283220). The lightweight factory hub may develop cracks on the outer wheel hubcentric surface over multiple long, endurance-type events and use. We have not seen any failures on street-driven or lightly-tracked vehicles. The updated Motorsport part has a full hubcentric mounting surface for less stress*.
* note that just because this is an updated part from BMW Motorsport and beefier than the original, it's not indestructible and still subject to stress, cracks, and failures.
Note that the rear bearing also changed at the same time. A new bearing is a wise addition but the new bearing design is not required. The change seems to be a minor one.
This is a part that we buy directly from BMW Motorsport. It was originally designed by Motorsport engineers for competition use in a factory BMW racing program. As a part designed for competition use, it does not have a warranty. BMW Motorsport parts may sometimes be in short supply and orders are released at the discretion of BMW Motorsport. If a part is not in stock, contact us for the latest estimate on delivery time.
For full BMW fitment information or for assistance from one of our BMW experts, we recommend calling us at 877-639-9648.