Originally Posted by
ParkingMeter
It only has to be done once, and it's usually cheap insurance for better bearing life and performance. HTH.
Agreed. I chase and face my BB and face my headtubes on every one of my own bikes and most of the bikes I sell. It does take some time, so it's not realistic for a shop to do it on every bike they sell. I would request it free on a bike $1000+ if it's not already done in the first place.
Yes, cartridge BBs will work fine on a painted BB shell. Remember though, even if the BB threads on straight, you can still have gaps between the shell and BB cup for water, dirt, sand, etc. to invade.
The headtube is just as bad if it's not faced. I've had more than a few bikes come through that felt like you were steering through a mixture of sand, mud, and glue. Surprisingly, one of these was a Gary Fisher Hi-Fi Deluxe. Simply prepping the headtube and reinstalling the headset did the trick.
Best case scenario in unprepped frames? Slightly increased bearing wear/overhaul intervals.