Bicycle Mechanics - old suntour front derailler...how does it work?

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spanky4x4
04-21-05, 08:04 AM
mid 70's suntour FD. front of the cage says suntour,and below that sl . on the back of the cage it has the made by info an 4532. instead of a hinged clamp it has a bolt on each side of the clamp. the spring pulls the cage up on the big ring, and when you pull the cable it shifts to the little ring. now for the problem.

the frame this came off of had a cable stop welded/brazed on the down tube,and there is a corisponding stop on the derailler. the cable routing was free from the shifter to the stop,a short piece of housing to the FD and free to the anchor point. the anchor point is fixed and does not move. the built in cable stop is part of the arm that pulls the cage in for the little ring. when I cable it up the way it was, nothing moves,cause the anchor doesnt move. I am missing something but I cant figure it out. I have tried it on the old frame as well and get the same result.

the way it is set up now is old suntour power rachet bar ends, housing to bolt on cable stops on the downtube,free cable to a clamp on cable stop on downtube,short housing to built in cable stop on derailler,free cable to anchor.

hopefully someone can point me to what I am doing wrong. it matches the rear derailler(suntour vx),and period fuji branded sugino cranks wonderfully,is lighter then the suntour blaze part that came off this frame,and its pretty to look at. thanks


Rev.Chuck
04-21-05, 08:31 AM
The housing ends in the arm that shifts the cage, right?
Does the der move freely when you shift it by hand?
Is the housing long enough to allow the arm to move? It needs to have some slack so it can move up and down with the arm.

spanky4x4
04-21-05, 08:35 AM
The housing ends in the arm that shifts the cage, right?
Does the der move freely when you shift it by hand?
Is the housing long enough to allow the arm to move? It needs to have some slack so it can move up and down with the arm.
yes
yes
I think so.I'll try longer to see if thats it. but I dont understand howit would work. tha cable gets sgorter as you pull it with the shifter. if its solidly anchored how does it move? is the short piece of hosing move? I mean in relation to the frame cablestop and deraillier stop ?


John E
04-21-05, 09:36 AM
I have owned several of these "normal high" front derailleurs. Pulling back on the shift lever forces the top of the short piece of housing upward, thereby effecting the gear change. This system is not compatible with today's under-the-BB cable routing, as it absolutely requires a cable [housing] stop at the forward end of the short piece of cable housing.