Originally Posted by
HerrKaLeun
So if we assume they are faced in the factory, why then ever worry afterwards? You mention Surly, which mostly is steel. But I assume they face them at the factory if needed? And I assume they face it before painting so that the faced BB is painted and doesn't rust.
Once the bike arrives at LBS I have a hard time believing mechanics take off the BB and face. Or are you talking if someone just buys a frame and builds a bike from ground-up?
I kind of see the need for facing in the manufacturing process, but have a hard time seeing the need to face afterward assuming this is a quality frame.
I don't think you're following the process or who does what and when.
Paint is one of the things that is supposed to be removed by facing. Aluminum doesn't rust, so aluminum frames are likely to be shipped faced with bare aluminum exposed.
If you buy a steel frameset, I would expect that frameset to come with paint on the BB face to protect it from rust. And then I would face it to remove the paint and square the face just prior to bearing installation.
If I bought a complete bike that came with the BB installed, I would assume that the installation included proper frame prep, including facing. If Surly (or whoever) installed a BB without facing the frame, they didn't install the BB correctly.
Every frame needs to have as squarely faced BB. For reasons I pointed out, this happens at different points depending on how the frame is sold and what it is made of. To this day, some frames are going to require facing at the LBS because it was purposely left unfaced by the factory. And all of that is assuming that everyone is doing things the right way, and not just sticking cups in a frame that has angled BB faces.
At the last shop I worked at, we always pulled the BB anyway on new builds, so if the frame was unfaced it would be pretty obvious. Faced metal is square, flat and shiny. And when you thread in the cup you'll feel it not evenly seat against the shell face.