Bicycle Mechanics - front derailleur compatibility

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tim00gle
09-05-09, 09:53 PM
Quick question, I've got an old trek 1400 that has all stock parts (older 7-speed 105, uniglide, originally DT shifters) but I've upgraded with Shimano 600 8 speed STI levers. I got the back working with the alternate cable routing method, but the front shifter definitely does not have enough cable pull to shift the front.
First off, is this normal? If it is, can I expect the shifting to work if I update the FD with a modern part like this?
http://cgi.ebay.com/Shimano-FD-2200-Braze-on-Front-Derailleur_W0QQitemZ370244187023QQcmdZViewItemQQptZCycling_Parts_Accessories?hash=item563445f38f&_trksid=p3286.c0.m14
operator
09-05-09, 10:53 PM
Lets ascertain that you're following a known method for setting up a FD properly, or that you know how to do it.
Panthers007
09-05-09, 11:10 PM
This is my Copy & Paste for the majority of FD problems:
___________________________________________________________________________________
Take the cable off the FD. Now install it from scratch as per Park Tool Repair:
http://www.parktool.com/repair/readhowto.asp?id=75
And BicycleTutor:
http://bicycletutor.com/adjust-front-derailer/
When you have it properly trimmed and are ready for the cable - a new one wouldn't hurt - you want to pull the cable taut - not too tight, taut. Then apply 48 to 60 inch-pounds to the pinch-bolt. Then put it through it's paces.
It's always easier and faster to install a FD from square-one, than it is to make adjustments with it already attached. This tends to fix one thing - while throwing another out of kilter. Start fresh. You'll get it.
Adding a barrel-adjuster can solve many problems with the cable coming loose - or being too tight.
tim00gle
09-05-09, 11:18 PM
Well after setting the low limit to *just* prevent chain rub and keeping the high limit loose, I first attached the cable normally, over the top of the bolt. Adjusted the tension with barrel adjusters but no go. So I attached the cable under the bolt, to allow the cage to travel more. Still not enough.
The alternate cable routing *might* have worked if the chainrings were pinned and ramped. But either way, the FD was hardly pushing the chain onto the next ring.
Anyways, from memory, the old FD looked like it had more mechanical advantage as compared to another bike's 10s 105 FD. This is why I ask.
Well after setting the low limit to *just* prevent chain rub and keeping the high limit loose, I first attached the cable normally, over the top of the bolt. Adjusted the tension with barrel adjusters but no go. So I attached the cable under the bolt, to allow the cage to travel more. Still not enough.
The alternate cable routing *might* have worked if the chainrings were pinned and ramped. But either way, the FD was hardly pushing the chain onto the next ring.
Did you perform the part about flipping the small shift lever several times before attaching the cable?
joejack951
09-06-09, 03:53 PM
I recently went through adding a compact crank to a 7 speed Trek 1200. I had to use a 9 speed chain to work with the 9 speed chainrings on the crank. After adding this chain, the front derailler no longer would complete the shift to the big ring unless I had the low limit screw set such that I had considerable rubbing in the small/big combo. I finally fixed the problem after giving in and buying a 9 speed front derailler. Shifts perfectly now.
Not sure if the above applies in your case but it's something to consider. The old 7 speed derailler had a different pivot set up which oddly had the cage somewhat lowering itself as it moved outward towards the big ring (7 speed era 105 FD). The pivots were at an angle to the frame unlike the new derailler where the pivots were parallel to the frame.
tim00gle
09-07-09, 06:44 PM
So has anyone been able to get an STI lever to work with a FD meant for friction shifters?
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