Headset and Bottom Bracket 'facings'?

FalconRider

Hi again,

I'm building a Whyte 46 from a brand new frame and I've been doing research, including watching videos, about fitting Headsets and Bottom Brackets.

Some of the 'experts' mention the issue of 'facing' the external surfaces of the frame but most don't refer to it at all.

My understanding of the term 'facing' is that it is the filing down of the external surfaces of the frame to bear metal to provide a smooth face to accept the Headset or Bottom Bracket.

Is this correct?

But is it actually necessary? What would happen if I don't bother to do this?

My Whyte frame appears to be superbly machined and I can't quite see how taking a file to the frame is likely to improve it. The opposite (damage) seems far more likely.

OK, there is some spray paint around the external surface of both the Headset and Bottom Bracket 'cups' but it's been evenly applied and can only be a few microns thick.

Do I need to worry about this issue at all with a quality frame?

If so, can anyone point me in the direction of some instructions on exactly how to 'face' these surfaces and what precautions need to be taken to avoid damaging the frame.

Thanks in advance.

FalconBirder

switchback18

You probably only ever need to face BB shells for external BB's. Once it's done it's done. If you want to be sure about the headset working smoothly I'd get that faced, especially if you're fitting an expensive one - seems a shame to cancel out the quality by having it misaligned.
However, I'd phone Whyte and ask them if this is something they've already done at the factory, then you'll know for certain.

nicklouse

i would run a facing tool over any frame i was building. just to see if it is needed.

but as mentioned above once it is done it does not need redoing.

the reason to do it is that the tools used make sure that the faces that the bearings press on are parallel to each other and are perpendicular to the axis of rotation.

this promotes the bearings to run true.

stumpyjon

To get it faced take it to your LBS, it'll take a couple of minutes. As Nick pointed out in a similar thread the tools required to face BB's are between £300 & £600 quid. My LBS did it for me for nothing as well as installing ny headset cups, crown race and star washer (but then again I had just spent £800 quid with them in parts ). Shouldn't cost too much or take very long anyway. It's not difficult to do any of these thins with the correct tools, they're just expensive, as are cock ups not not doing it correctly.

dennisn

FalconRider wrote:

Hi again,

the term 'facing' is that it is the filing down of the external surfaces of the frame to bear metal to provide a smooth face to accept the Headset or Bottom Bracket.

Is this correct?

But is it actually necessary? What would happen if I don't bother to do this?

Do I need to worry about this issue at all with a quality frame?


FalconBirder

The "facing or filing" part is not so much to provide a smooth surface as to assure that
the two surfaces are parallel with each other so the bearings run square and not
at an angle to each other. To be honest I have never done it or had it done to any bike
I have ever owned(and I go back a bit). It was never much of an issue until outboard
bottom brackets came out. Now however maybe "stumpyjon" is right on the money in that
the shop can do it quickly and cheaply and you will have a bit of peace of mind. As far as
the head tube goes you might as well get it done also as long as it's in the shop. Just
remember that while it my be called "filing" by some, it is only correctly done with tools
costing several hundred dollars(see the Park Tools website) and definitely NOT with
a hand file.

Dennis Noward