FD for an old MTB
10-14-19, 07:31 PM
#26
Senior Member
It appears, based on the second photo by the OP, that this FD has an adjuster for the spring tension. It's the allen bolt next to the inner cage, right above the chain in the 2nd photo. Depending on its current orientation, it may be possible to increase the return tension. There should be arrows on both the bolt and the body. Aligning the arrows is for standard (lower) tension, arrows at 180 degree is for higher tension.
If it's currently on lower setting, this adjustment may give you what you need to overcome the cable friction.
If it's currently on lower setting, this adjustment may give you what you need to overcome the cable friction.
10-15-19, 08:01 AM
#27
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It appears, based on the second photo by the OP, that this FD has an adjuster for the spring tension. It's the allen bolt next to the inner cage, right above the chain in the 2nd photo. Depending on its current orientation, it may be possible to increase the return tension. There should be arrows on both the bolt and the body. Aligning the arrows is for standard (lower) tension, arrows at 180 degree is for higher tension.
If it's currently on lower setting, this adjustment may give you what you need to overcome the cable friction.
If it's currently on lower setting, this adjustment may give you what you need to overcome the cable friction.
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Stuart Black
Plan Epsilon Around Lake Michigan in the era of Covid
Old School…When It Wasn’t Ancient bikepacking
Gold Fever Three days of dirt in Colorado
Pokin' around the Poconos A cold ride around Lake Erie
Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
10-15-19, 08:58 AM
#28
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IIRC, early 90s Treks had a weird FD cable routing strategy. At least some of them had a pinch bolt on the frame, as OP's does, and a stop for the housing on the actuating arm of the derailleur, and no pinch bolt on the derailleur.
It is very hard to tell form the OP's pictures, but I think that setup has been modified on their bike. It almost makes me think someone has added the pinch bolt on the derailleur where there would not have originally been one.
If you got a compatible bottom-pull derailleur, if you could swap the cable pinch bolt for the cable housing stop on the existing derailleur, that might work.
It is very hard to tell form the OP's pictures, but I think that setup has been modified on their bike. It almost makes me think someone has added the pinch bolt on the derailleur where there would not have originally been one.
If you got a compatible bottom-pull derailleur, if you could swap the cable pinch bolt for the cable housing stop on the existing derailleur, that might work.
10-15-19, 12:24 PM
#29
Senior Member
I think you are mistaken. I haven't run across any front derailer...or rear, for that matter...that has any kind of adjustment to the spring tension, especially not lower to middle of the line Shimano and not old stock. There's no Allen bolt on that derailer other than the cable anchor and the clamp.
A few RDs also had adjuster (eg: RD-6401, RD-M735). These were also 1990 vintage. These were the older design that used a coiling action spring, as opposed to the more modern pulling spring, (the spring that can be seen running the length of the parallelogram). The adjuster was a screw located on the parallelogram right under the cable anchor point.
FD-M550 LX Tension adjuster
Edit: Post #29 & photo was to show the return spring tension adjuster and is not related to the cable routing/attachment that others have explained.
Last edited by KCT1986; 10-15-19 at 03:22 PM. Reason: For clarity
10-15-19, 01:29 PM
#30
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Try routing your cable housing from the top tube cable stop to the cable stop on the derailleur (I think this is how the housing is routed in the first set of pictures), and anchor the inner cable to the bolt on the frame. Do not anchor the cable to the bolt on the derailleur. This was how these bikes came from the factory.
10-15-19, 01:36 PM
#31
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Here is how the connection was described in a different discussion:
https://groups.google.com/forum/#!to...ch/CJwcCaeZV9M
https://groups.google.com/forum/#!to...ch/CJwcCaeZV9M
I have a 1992 TREK 970 frame with top tube cable routing. There is a cable
housing stop for the front derailleur on both ends of the top tube. There is
no other stop before the cable housing reaches the front derailleur but there
is an anchor bolt beyond it on the bottom bracket shell just below the
chainstays.I have a picture of the built up bike and it appears the cable & housing goes
from the rear stop on the top tube to all the way to the front derailleur,
beyond that only the cable extends through the derailleur and appears to anchor
on the bolt down on the bottom bracket. The front derailleur does appear to
have some kind of housing stop on it.
housing stop for the front derailleur on both ends of the top tube. There is
no other stop before the cable housing reaches the front derailleur but there
is an anchor bolt beyond it on the bottom bracket shell just below the
chainstays.I have a picture of the built up bike and it appears the cable & housing goes
from the rear stop on the top tube to all the way to the front derailleur,
beyond that only the cable extends through the derailleur and appears to anchor
on the bolt down on the bottom bracket. The front derailleur does appear to
have some kind of housing stop on it.
10-15-19, 03:10 PM
#32
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Aha so housing pushes derailleur arm down. Interesting setup!
