This ring is what holds the bearing in place inside the hub assembly. While not always a replacement part it's a good idea to have one on hand in case the original is damaged or is flung to parts unknown during removal.
This is a Genuine BMW locking ring with a two year warranty. Buying a Genuine part will usually be more expensive than an OEM or aftermarket brand but you are assured that it meets BMW's designs for fitment, performance, and longevity. It will also be the very latest design, incorporating any updates or revisions that an aftermarket brand typically will ignore.
BMW Fitments:
1 Series
E82 / E88 (08-13) > 128i
2 Series
F22 / F23 (2014-2021) > 228i
F22 / F23 (2014-2021) > 228i xDrive
F22 / F23 (2014-2021) > 230i
F22 / F23 (2014-2021) > 230i xDrive
F22 / F23 (2014-2021) > M235i
F22 / F23 (2014-2021) > M235i xDrive
F22 / F23 (2014-2021) > M235i-Racing
F22 / F23 (2014-2021) > M240i
F22 / F23 (2014-2021) > M240i xDrive
F22 / F23 (2014-2021) > M240i-Racing
3 Series
E30 (84-91) > 318i
E30 (84-91) > 318is
E30 (84-91) > 325e
E30 (84-91) > 325i
E30 (84-91) > 325is
E30 (84-91) > 325ix
E30 (84-91) > M3
3 Series
E36 (92-99) > 318i M42
E36 (92-99) > 318i M44
E36 (92-99) > 318ic M42
E36 (92-99) > 318ic M44
E36 (92-99) > 318is M42
E36 (92-99) > 318is M44
E36 (92-99) > 323ic
E36 (92-99) > 323is
E36 (92-99) > 325i
E36 (92-99) > 325ic
E36 (92-99) > 325is
E36 (92-99) > 328i
E36 (92-99) > 328ic
E36 (92-99) > 328is
3 Series
E46 (99-05) > 323Ci
E46 (99-05) > 323i
E46 (99-05) > 325Ci
E46 (99-05) > 325i
E46 (99-05) > 328Ci
E46 (99-05) > 328i
3 Series
E90 / E91 / E92 / E93 (06-13) > 325i
E90 / E91 / E92 / E93 (06-13) > 328i
3 Series
F30 / F31 / F34 (2012-2019) > 320i
F30 / F31 / F34 (2012-2019) > 328i
4 Series
F32 / F33 / F36 (14-20) > 428i
5 Series
E34 (89-95) > 525i M20
E34 (89-95) > 525i M50
Z Series
E36/7 / E36/8 Z3 (96-02) > Z3 2.5
E36/7 / E36/8 Z3 (96-02) > Z3 2.8 97-98
E36/7 / E36/8 Z3 (96-02) > Z3 2.8 99-00
E36/7 / E36/8 Z3 (96-02) > Z3 3.0
Z Series
E85 / E86 Z4 (03-08) > Z4 2.5i M54
E85 / E86 Z4 (03-08) > Z4 3.0i M54
E85 / E86 Z4 (03-08) > Z4 3.0i N52
E85 / E86 Z4 (03-08) > Z4 3.0si N52
Z Series
E89 Z4 (2009-2016) > Z4 sDrive28i
E89 Z4 (2009-2016) > Z4 sDrive30i
E89 Z4 (2009-2016) > Z4 sDrive35i
E89 Z4 (2009-2016) > Z4 sDrive35is