"so do you understand the symptom I'm trying to describe? I've seen it on indexed systems as well, but never been able to really figure the problem or fix."
Yeah I thinkg I've got it. When you go to shift up or down in the front, but especially up to the bit ring the chain just kind of jumps around, wants to climb up, but just sort of slips, makes noise etc. right?
The problem with these old systems is no ramps or pins, only 4 profiled teeth to pick up the chain or allow the chain to drop easily. The key to snapping up the shift is to allow the front cage to move just a bit more than is recommended for a modern system, yet not let it move so much that you drop the chain off the crank. It's touchy but not hard to do. And there's no "perfect solution" for the porblem especially on older worn rings. It will never be near as good or as snappy as say a modern STI system. You just have to fiddle with it and get it as good as you can. Just a little side note. The shifting in the front with a friction thumby will be best when the rear is in the middle of the cassette. It will be at it's worst when in either the small or large cog in the rear when going for a cross chain configuration. Cross chaining on the old 5 speed/double set ups isn't that critical as the angle of the chain isn't that severe, and those ranges are usable when riding. So you still need to be able to make the shifts, but it can be a pain to get it to happen smoothly. Just work at it and get it the best you can. That's all you can do. Good Luck. :thumbsup:
Good Dirt
Yeah I thinkg I've got it. When you go to shift up or down in the front, but especially up to the bit ring the chain just kind of jumps around, wants to climb up, but just sort of slips, makes noise etc. right?
The problem with these old systems is no ramps or pins, only 4 profiled teeth to pick up the chain or allow the chain to drop easily. The key to snapping up the shift is to allow the front cage to move just a bit more than is recommended for a modern system, yet not let it move so much that you drop the chain off the crank. It's touchy but not hard to do. And there's no "perfect solution" for the porblem especially on older worn rings. It will never be near as good or as snappy as say a modern STI system. You just have to fiddle with it and get it as good as you can. Just a little side note. The shifting in the front with a friction thumby will be best when the rear is in the middle of the cassette. It will be at it's worst when in either the small or large cog in the rear when going for a cross chain configuration. Cross chaining on the old 5 speed/double set ups isn't that critical as the angle of the chain isn't that severe, and those ranges are usable when riding. So you still need to be able to make the shifts, but it can be a pain to get it to happen smoothly. Just work at it and get it the best you can. That's all you can do. Good Luck. :thumbsup:
Good Dirt