have fitted another couple of external bottom brackets today.... frames were not faced by me but assured by on one as made faced so i just dressed the paint off with a file.
but why the fuss to face them anyhow? two things on my mind. first, and most important, when you have screwed around 10mm of thread into a tight fitting shell there is no way that the bearing housing is going to move in those threads as you nip it up against the face? second, plastic spacers are going to squidge a bit anyhow and take up any misalignment?
of course sloppy threads / hamfisted cross threading / seriously misshapen shells are something else, but for the vast majority of frames is it needed?
most bearings i've had fail went because the water got to them and they had bugger all grease in them to start with. now loads of marine grease in when they are first fitted seems to make them really last.
views?
agreed
Yes....I think so too. Bike shop myth, if it were true we would use finely machined spacers made of alloy, for exact fit not offcuts from plumbing pipe! Fitted a hope BB last night and the spacers all squashed when I tightened it. They always fail because the grease gets washed out. I fitted another hope one 9 months ago and it is still sweet as, so took the plunge on another after killing yet another shimano one. Facing brakes I can see the point of if you have IS brakes like I do, however if you have post mount it's totally pointless.
I don't get it either
I would get it done, probably a cobblers is not the best place to do it...
yup cobblers, no need whatsoever.
(see thread below for other views)
I don't "get" bb facing either
It makes your friendly local bike shop some money for very little work 😈
Personally I never bother 'cause I can't see the point. Never had a problem.
splendid, that's that sorted out then.
no it's not cobblers ..if stw hadn't crashed recently i'd have linked to a recent thead. as usual it depends whether you want advice from em
not cobblers at all.
makes a difference but how much is debatable
maybe loads ...maybe only a little bit ..depends on how the bb shell is faced from new.
I've never ever faced a bb shell & I've never ever had any problems. Same with caliper mounts.
i had the one on my intense done because the paint was quite thick round the BB, but didnt bother on my anodised on one.
zero expertise here and would consider myself a dull old trail rider - probably clock up less miles in a month than some do in a week
in last 12 months put a HT11 on old Trek Easton frame to build a CX stylee fugley and a Race Face god knows what external BB on my Merlin Malt HT cos it was cheapish and old cassette bearing was shagged - both times they nipped up neat and from my point of view seem sweet - now i clean up a bit -tooth brush and whatever solvent comes to hand and use a torque wrench as to being square well ... it should be and if it isn't then the shaft isn't going to slide thru - essential no
or read this thread http://www.singletrackworld.com/forum/topic/bb-shell-to-face-or-not-to-face