Does anyone know what the proper name for those plastic top hat shaped sleeve that the axle runs through on external BB (mine's a Race Face by the way, but Shimano are similar) and where to get them?

CRC and ukbikestore are out of stock but you get the point.

http://www.chainreactioncycles.com/Models.aspx?ModelID=39505

silverfish

http://www.silverfish-uk.com/products/468-race_face_bike_components_x-type_bearing_cap.php?r=1m6d5b7s0

No idea what they're called, but you get one free with every external BB from what I remember!

Sorry. IGMC.

Thanks for that – I thought that might be the fellow, but the photo doesn't show the profile. If, as on Hope BBs, the axle runs directly through the bearing, is there not a danger of the bearing seizing on the axle? I can't decide whether to replace the whole BB with a 'better' one or just put some good quality bearings, suitably packed with grease, in the existing Raceface cups.

BETD bearing abandon the plastic sleave as well, never really made sense to me having it their in the first place

If your carefull they can be removed and refitted, I wasnt and mullered mine so bough a new BB.

There's a killing to be made I'm sure if an engineering firm was to make a set of bearing cups that took bearings and a top hat bushing and sold a good supply of spares.

i.e.
Sell an almost identical BB to the £20 superstar one for £50 but with SKF/FAG etc bearings.

Then suppourt it with bearing kits for £22 (about retail price for SKF bearings) and relacement top hats if they get destroyed for a reasnoble cost (say £5).

My main gripe with the hope ones is the lack of a top hat. Might go for an acros one as £60 for 2 years is about what I'd spend on shimano ones and I'm confident I could destroy one inside 2 years!