Bicycle Mechanics - Tight FD problem

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rogerstg
02-15-08, 06:48 PM
I installed a triple and a new Tiagra FD. The problem that I have is that it is very difficult to up shift from the STI lever. Especially from the medium to the big ring: which is the end of the range. The entire drive train is new and I’ve rechecked and relubed everything.
I’ve tested the spring action of the FD and found it to be heavy compared to several others including another 9 sp Tiagra. The two models look a bit different, with the problem unit being newer.
FWIW, the problem unit exceeds the capacity of a 15# scale when moving from middle to big ring. Other, older FDs measure 8-11 # in that area.
My questions are:
Is there any way to adjust the return spring? There is no obvious way to disassemble the unit because it seems to be assembled with swaged pins.
Is this the norm for new Tiagras? A new unit is pretty inexpensive, but I don’t want to buy another problem.
Any help will be appreciated.
kramnnim
02-15-08, 07:01 PM
Some shimano FDs have an adjustable spring, but you would've seen it if yours has it...a cam shaped...
"thing" you can twist with a flat screwdriver.
Ex Pres
02-15-08, 08:18 PM
May seem odd, but have you tried loosening the high limit screw?
rogerstg
02-16-08, 06:52 AM
May seem odd, but have you tried loosening the high limit screw?
As part of checking things out I did loosen the hl screw. AFAIK that screw only provides a stopping point for the cage travel and has no effect on tension. Thanks.
Bill Kapaun
02-16-08, 12:28 PM
Donwnload the installation document from the Shimano site-
http://techdocs.shimano.com/techdocs/blevel.jsp?JSESSIONID=H34Lsv6yRJ1QGQlckZGn83tvC8TrQnym9mWMJkdC1xysyFnQVW7s!-1970199853&ASSORTMENT%3C%3East_id=1408474395181679&FOLDER%3C%3Efolder_id=2534374302051921&bmUID=1203189896959
Not to sound insulting, but did you remove the "Pro Set Alignment Block"?
rogerstg
02-16-08, 02:01 PM
Donwnload the installation document from the Shimano site-
Not to sound insulting, but did you remove the "Pro Set Alignment Block"?
Thanks for the suggestion, but the alignment block has been removed and I reacquainted myself with the tech documents when I started having the problem. BTW, the alignment block would have prevented downshifting - at the very least. ;)
It's looking like I just have a bad unit. My guess is that it was manufactured too tight. It will probably be alright with downtube or bar end shifters, but it's a bit of a PIA with brifters.
Actually I had a Tiagra FD that I would just about break my fingers off trying to shift onto my big ring. After nearly crashing because I was so frustrated and tried using both hands to shift, I loosened the pivot screw and applied some penetrating lube then retightened it (though not likely as tight) and have had no problems since.
Is it still too tight with the cable released from the derailleur?
Ex Pres
02-16-08, 06:11 PM
As part of checking things out I did loosen the hl screw. AFAIK that screw only provides a stopping point for the cage travel and has no effect on tension. Thanks.
You're right that it doesn't affect tension, but it can made it impossible to reach the outside "rachet point"; and if it's too tight, it can make it a bear to shift back to the lower rings.
rogerstg
02-17-08, 06:03 AM
Actually I had a Tiagra FD that I would just about break my fingers off trying to shift onto my big ring. After nearly crashing because I was so frustrated and tried using both hands to shift, I loosened the pivot screw and applied some penetrating lube then retightened it (though not likely as tight) and have had no problems since.
The problem with the 4503 is that there is no pivot screw. All pivot joints are pinned. I did use penetrating and other oils that made a very slight difference. Ive swapped it with a 4403 from another bike and that works fine.
I thought that maybe this might be an issue of the wrong product for this application. Since no one has mentioned this I assume that it's simply defective and will buy another one for $35.
Thanks to everyone that took the time to read this thread and reply.
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