Originally Posted by
Beemer
Firstly should the front changer cable route only go around the BB or should it then go around the chainstay joining piece? I ask this because the cable route to the Ultegra front changer clamp is just clearing the mechanism.
You mean looped behind the bridge between the chainstays just behind the BB? I've never seen any FD cable looped this way. Not sayin' it wouldn't work, but it seems an odd angle to have the cable go that far back.
Originally Posted by
Beemer
Secondly, the BB cable guide tubes have split wire retainers.
If they are what I think you are describing, i.e. cable guides riveted to the the bottom of the BB, then no you don't want to open them up. Thread the cable through them and run it directly up the back of the BB to the derailleur. If your derailleur is a type that requires a section of housing because the part that moves is the housing stop instead of the cable anchor on top, then you can't use those guides. You'll need to add a DT housing clamp anyway so run the housing any way that fits under or even on top of the BB. If your derailleur doesn't require the housing, then run it through the guides, and yes it may rub on the DT or be very close to it.