Top Pull or Bottom Pull Derailleur?

[jckid]

How do I determine if I need a top pull or bottom pull front derailleur?

[Marburg]

Figure out how your front der cable is routed. If it comes at the derailleur from the bottom (i.e. wraps around the BB then comes up the seat tube, as on most road bikes) you need bottom pull. If it approaches the der from the top (some/many cross and mountain bikes) you need top-pull.

Just don't ask me to explain top- and bottom-swing. I can't keep that junk straight.

[Dude]

top swing and bottom swing is pretty simple. If the clamp is below the fr der cage, it is top swing (the cage is swinging above the clamp). If the clamp is above the cage, it is bottom swing. All road derailleurs are bottom pull, bottom swing.

[aaronbarker]

I was building a cane creek cross bike frame trying to use what i had in spare parts. only having a bottom-pull front D, I ended up getting a 'helper pulley' set-up ordered from the QBP catalog to route the top pull oriented cable down to the pulley and then back up to the front D. It's a 1" dia. pulley that clamps to the seatpost tube just above the BB shell. I've seen a similar set-up on some cross-commuter bikes with the pulley actually factory-attached to the seatpost just above the BB shell. Fun problem to solve for me.....

have fun,
aaron