cavernmech

I am building up a new 29er mtn bike for myself. I need to order a couple of parts I dont currently have. One of these is a new front derailleur. I know I need a Top-Pull and I know its a 31.8 diameter. The one thing I am not sure of is what is the difference/purpose of Top Swing/Down Swing? This will be a 2 X 9 set-up using SRAM XO shifters and a X-9 rear mech.

kenhill3

Top swing has the derailler pivoting ABOVE the band clamp, down swing has the derailler pivoting BELOW the band clamp.

I researched this recently, by coincidence, and there is really no significant functional difference. The only thing that may determine choosing one over the other is interference problems as far as where the band clamp is on the seat tube- suspension pivot or rocker mounts may get in the way of one or the other band clamp locations.

cavernmech

Its an XL hardtail frame so no suspension placement issues. Thanks for the clarification.

wmodavis

I had purchased a Shimano component set and it had a top swing FD. The frame I fust finished building up had a weld at the base of the seat tube which interfered with mounting the FD. Fortunately the LBS where I purchased the components did an even trade and all is OK now. So it seems like the frame configuration is the real deciding factor. If both will work you get to decide for yourself.

ginsoakedboy

True. Function is the same -- the determining factor is whether you have interference or a non-traditional frame that determines where the clamp must be located.

I have XT components on both of my bikes, one with a top swing, and one bottom swing. They both function equally well. The seat tube on one bike is slightly flared toward the bottom where it meets the BB shell, so the top swing wouldn't work because the clamp wouldn't fit around the flared part of the tube. I had to use the bottom swing so that the clamp could go higher up the tube where it was perfectly round.