Tapered Bearings Question

[comet]

MCI 51W outer; 31W bearing and inner

[Jordan Nygaard]

Thanks for the quick response. By inner and outer do you mean inside and outside dimensions of the bearings?

[ahistand]

I have had no luck with finding the correct size bearings from my local bearing houses. I believe the correct size is 34w 51w and this refers to the size, inner and outer respectively of the bearing races in millimeters. Ed Korn sells them for like 36 bucks or something reasonable anyway.

[schrader7032]

Vech in Missisippi at Benchmark Works also carries the bearings.

Kurt in S.A.

[Dr. Curve]

I thought they were the same as the ones used in a /5. No?

[Allan.Atherton]

I thought they were the same as the ones used in a /5. No?
The tapered bearings fit the stem of the Earles fork. The stem of the US fork is smaller and requires adapters - steel rings that fit between the stem and the bearing.
See
http://members.aol.com/VechBMW/index.html
31 42 2 000 000--$49.95--tapered roller bearing set for steering head R5-R71 R24-R69S (US fork requires two adapter rings 31 42 2 000 001).
31 42 2 000 001--$40.00--adapter for use with 31 42 2 000 000 steering head bearings for 1969 US fork two required.
The /5 fork takes something else entirely:
07 11 9 985 070--$71.00--tapered roller bearing set of 2 for steering head R50/5-R100RT

[Dr. Curve]

Thanks Allen. I have lots of new bearings here at the shop for everything from 1970 on.........I will check those other numbers out. Are the bearings that go in the earls fork elbow joints the same as would be used in the triple tree............or are they ones that would later be used in the /5 triple tree. Seems that along the way we noticed that some bearings could be exchanged between a /2 and a /5 but if not.......thanks for letting me know right now.

[Allan.Atherton]

... Are the bearings that go in the earls fork elbow joints the same as would be used in the triple tree... or are they ones that would later be used in the /5 triple tree...
Earls fork pivot bearings are different part numbers and bearing numbers than tapered steering bearings. I think they are smaller, and may be plain roller bearings - I can't remember.
Another source of bearings is Ed Korn's Cycle Works at http://www.cycleworks.net/. They will be cheaper there than any other vintage BMW vendor. The bearings are faintly electro-etched with decent brand names, and are probably made in various plants world-wide. I believe he orders them in bulk and repackages them in generic boxes. The other approach is to buy bearings engraved with brand names and numbers, in official branded boxes, which is what I think Bench Mark Works and bearing stores sell. I have used both and don't know the difference aside from cost.

[VBMWMO]

Does anyone know the number stamped on the bearings so I can purchase them locally. I would like to replace the ball bearings in the steering head with tapered roller bearings that I have read about. Thanks in advance.. Jordan