E39 M5 wheel bearing, part number confusion...
Discussion
Morning all.
The LH front wheel bearing on my 5 is starting to give a gentle groan occasionally on RH corners, so I had a look at what it was going to cost...
I was pleased to see that BMW do a valueline bearing kit, which can be seen here:
http://bmwfans.info/parts-catalog/31222326578/
Now, the issue is, the bearing listed as part of that kit, 31 221 093 427 is the bearing listed against everything except the M5, which is bearing 31 222 229 360.
Has anyone any knowledge of whether this is a mistake? Are the bearings physically different between the M and non-M cars? Or are the bearings physically identical, but perhaps higher rated on the M and BMW later commonising the parts?
The M5 uprights are the standard V8 uprights, so are shared with the 540 and early 535. This would seem to indicate that the bolt positions are the same for the hub assemblies, but perhaps the offset of the wheel/disc mount flange is different on the M5?
The LH front wheel bearing on my 5 is starting to give a gentle groan occasionally on RH corners, so I had a look at what it was going to cost...
I was pleased to see that BMW do a valueline bearing kit, which can be seen here:
http://bmwfans.info/parts-catalog/31222326578/
Now, the issue is, the bearing listed as part of that kit, 31 221 093 427 is the bearing listed against everything except the M5, which is bearing 31 222 229 360.
Has anyone any knowledge of whether this is a mistake? Are the bearings physically different between the M and non-M cars? Or are the bearings physically identical, but perhaps higher rated on the M and BMW later commonising the parts?
The M5 uprights are the standard V8 uprights, so are shared with the 540 and early 535. This would seem to indicate that the bolt positions are the same for the hub assemblies, but perhaps the offset of the wheel/disc mount flange is different on the M5?
I seem to have managed to stumble upon the answer on a website named zeckhausen.
The bearings in terms of geometry, bolt pattern and such are identica. Looking at a picture, there seems to be a shape difference in the upright mounting flange, but it's not related to function, it just appears that the M5 unit is a little lighter.
The mechanical difference is in the disc mount face. The M5 part has 3 pins pressed into it, which locate into mating holes on the M5 disc. It still has the disc retaining screw too.
Effectively, the non M5 bearings will fit the M5, but won't have pins to engage, but the M5 bearing absolutely will not fit non M cars as the pins will prevent an incorrect disc being fitted.
I'm not sure what the pins are there for other than that. Alignment will be made via the hub spigot, assembly security via the retaining screw, and load bearing is always from the joint clamp load from the wheel bolts. Well, it at least explains why BMW are selling non M bearings for M5's.
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