Or can i just bang in the external BB as it is?

Never usually face frames and have never suffered in the past because of it but the shell is totally painted on the Inbred so don't know if it makes any difference as it is usually paint free.

I will bow to the collective wisdom of the STW massive…..
Cheers.

Yes

Depends on your attitude to stuff is. If you'll be hacked off that your BB might not last quite as long then do it (notice the word might, it might also be fine).

On hack bikes I tend to carefully file any excess off myself, haven't had any problems yet, and actually those bikes tend to get more mileage than the ones kept for 'best'

Or can i just bang in the external BB as it is?

Suspect "banging" it in might not be the best option mate, might ruin the threads on the BB and/or the BB shell! 😉

Sorry…

Seriously though, it is wise to get BB shells faced for external BB bearing life, though I think it's less critical since Shimano seem to have been supplying plastic spacers with the BB's rather than the metal ones they used to.

Wise to get it done if you're keeping the frame long term though, and even more so the head tube and disc brake mounts (if you're running IS mount calipers). Headset bearing life is probably way more critical to a good fit coming from a flat tube surface than BB bearing life.

Pop down the LBS, see what they charge, last time I had to get a frame done they charged me £20 for head tube, BB shell and disc mount faced all in one… Not bad really when you consider it.

Oh, and I ordered a Purple one by the way… Mandatory pics when you've finished the build please!

Well you could buy a BB from France interestingly, it seems that none of the shimano BB I have seen install here seems to have the problem the UK ones have. Plus none of them have been installed on a faced frame…

You could also get a Rotor BB. They have self aligning bearings

+1 for MaverickBoy, it's £20 for the whole shebang FFS. just get it done.

A

well I dunno, but I contacted orange and they advised me not to have my P7 bb shell faced.

Can someone point out to me where Shimano say frames need facing. Except in a few exceptional cases it's a load of rubbish.

Though for those that do believe in frame facing, I do bike-blessings – it's only a tenner (£20 for the deluxe one) and it might make a difference so "just get it done". I can even do it via the web so just drop me an email.

Hoi clubber bike blessing is my business 😉

clubber – Member

Can someone point out to me where Shimano say frames need facing. Except in a few exceptional cases it's a load of rubbish.

Though for those that do believe in frame facing, I do bike-blessings – it's only a tenner (£20 for the deluxe one) and it might make a difference so "just get it done". I can even do it via the web so just drop me an email.

Clubber +1

Screw in the bearings and then see if the axles goes through nice and square (i.e. aligns with the opposing bearing) – if it does, no need for facing!

Can anyone that faces bbs state that they've found one that was off? (bar paint)

In all the frames I have bought in the last few years all have arrived faced (although obviously not checked physically) 2 Kinesis XC2's and an Orange Five. All have NO issues with BB longevity (Hope BB's and XTR). So I would say on modern frames are all faced now the Ext BB is STD 🙂

And just to add once again, almost all facing tools (there are a couple of exceptions but they're so unusual as to ignore) only ensure that the face is square to the BB thread. They do NOTHING to ensure that the BB cups on each side are actually in line with eachother.

If you trust the manufacturer to get the threads in line then why don't you trust them to get the faces straight? Getting faces straight is pretty easy from a manufacturing POV, especially if the BB is turned whereas getting the threads on each side in line is much harder.

I can face it for you with a lump hammer, can also drive the bearings in at the same time, payment will be free and I'll bring the dwarfs in the fire engine 😀

Can anyone that faces bbs state that they've found one that was off

PP did – IIRC it was a Sanderson that he said was a good mm or two off in place but as I stated, I just don't believe that it's common.

Are not bottom bracket shells cut from steel tube? If so the tube must be assumed to be tubular given the manufacturing process in place. The cutting won't be done by some YTS lad with a hacksaw, but on a proper rig, and probably computer controlled. So why then should the opposite faces be anything other than parallel to each other? Why then is there a need to use a tool that cannot be guaranteed to have parallel faces to alter what until the last few years was always considered to be perfectly acceptable.

It's the "I'm sh*t scared of everything" brigade who have pushed the absolute need to have BB cups faced.

No, I reckon it's the distributors who wanted to avoid warranty claims on failed BBs so claimed that it was because the frames hadn't been faced.

Typical bike industry bs.

read somewhere that the welding process can ever so slightly change the shape/angles of the BB tube when they are welded in.

having said that, i've never bothered. i scraped the paint from the ends of the BB shell, but never bothered facing it.

Well i had it done this morning at my very friendly LBS for the princely sum of £5. They also chased the threads through in the BB shell as the Raceface BB was not screwing in easily (it did afterwards).

They looked at the Headtube and disc mounts and said not to bother as they seemed fine as they were. Just got to build the rest of it up now and try to get the whole slidy dropout thing working as i've not had one before.

Sliding d/o are easy – the biggest thing is to do them up very tight or they will move! Do that though and they're great.

I never quite saw the reason for facing the frame for external BBs. By the time the BB gets up to the face of the frame there is 30mm or so already screwed into a close fitting tube. I can't see how the frame face being uneven would throw it out of line, even if its massively over tightened. Seems to me its far more important that the threads each side are in line, like someone above said.

swamp boy, if you ever screw in a bb you'll see how much play there is in the threads.

However it seems bizarre to me that the shell will distort.