Originally Posted by
Smokinapankake
So the boss on the rear of the seat tube is a mount for a front derailleur cable pulley (missing). Cable comes down, wraps around the pulley, and back up to front derailleur, mimicking an under the BB cable routing. Fairly common practice in those halcyon days of MTB innovation.
Yes, the scoring on the BB shell is concerning. Not sure what to do about it though. I haven’t had a lot of time to really dig into this frame yet, but I’ll be sure to keep you all updated as things move along. For now I’m just soaking in the experience!
Perhaps some frame builders could pipe up. My hazy knowledge of metallurgy makes me think it would be easy to fill and touch up with gloss paint, reducing the chance of a stress riser that could crack the BB. I once pounded over and into a railway crossing and my BB that split right across the bottom, parallel to the spindle.