Shimano GC Shimano BB-7200 GB-100 DURA ACE Bottom Bracket 68mm 116mm 35xP1 French (LN)

[woodbutchmaster]

If the lockring g stays locked why have it faced?

It stayed locked well enough, in fact it took several hours of immersion in white spirit before it eventually came loose.
What concerned me was that because the ring did not fit flush to the edge of the b/b, it left a gap through which water had penetrated and consequently the thread of the b/b shell had corroded .

 

[midlife]

Water usually finds a way in , the gap between the axle and the cup is probably the easiest portal, Google campagnolo rifled cups to see a hopeless attempt to stop it. Sealed bb's have no lockring if you are looking to replace.

 

[woodbutchmaster]

Water usually finds a way in , the gap between the axle and the cup is probably the easiest portal, Google campagnolo rifled cups to see a hopeless attempt to stop it. Sealed bb's have no lockring if you are looking to replace.

Yes thats the conclusion l have come to, try to sell the Shimano b/b and buy a sealed unit , not very 1970's but much less of a problem in the long run.

 

[rogerzilla]

Facing is good anyway, because these BBs have a low tolerance for misalignment. The only BBs that really don't need the shell facing are the type with no lockrings or flanges, held in by friction or Loctite. Many cartridge BBs only need the RH side of the shell facing.

 

[woodbutchmaster]

Facing is good anyway, because these BBs have a low tolerance for misalignment. The only BBs that really don't need the shell facing are the type with no lockrings or flanges, held in by friction or Loctite. Many cartridge BBs only need the RH side of the shell facing.

Thanks for the info. The rebuild project is now on a back-burner until the autumn because the guy who will be doing the respray is fully booked until September ( he really is very good , he resprayed a side panel on my Ducati and l can't tell the difference between it and the other side) only the best is good enough !

I know, its outside of cycle chat normal boundaries ...but hey it is still a bike