Bicycle Mechanics - top pull front derailleur very difficult to shift onto large chainring
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03-28-07, 12:30 PM
front derailleur - shimano lx gold top pull
shifter - shimano deore dual control levers
everything hooked up and tight, cable lubed inside the casing, derailleur moves fine and free with fingers.
this is how the cable is attached to the derailleur, click for larger image, yellow line is cable.
coming from the top, lopped under the bottom guided by a groove in the body of the derailleur, bolted down when it comes around and is on top.
03-28-07, 12:36 PM
When you say difficult, what exactly is it doing? Did you check the outer limit screw?
+1 for the outer limit screw. Next, make sure in the lowest chainring, that you have the correct cable tension. If it's loose, it's not going to work.
03-28-07, 01:36 PM
is this a top pull derailleur? the type that accepts the cable from the top? this is the derailleur i have.
the limit screws were not the issue, i checked them.
That's a bottom pull derrailleur. If you can't shift, your shifter could also be gummed up and not catching.
03-28-07, 03:21 PM
If you physicall have to PUSH hard to get it to shift, this can be an indication that the cable tension is to tight. Loosen the cable tension.
03-28-07, 04:44 PM
so, as a bottom pull derailleur, it should not be used on a atb bike that gives it the cable from the top, from the toptube, right? i ask b/c i am going to indonesia sunday and have to find out fast so i can next day air a derailleur for my frame.
loosen the coiled spring tension in the derailleur? or the brake cable? how would i loosen the coiled spring tension (that is a good idea) if that is what you ment?
03-28-07, 05:10 PM
If you physicall have to PUSH hard to get it to shift, this can be an indication that the cable tension is to tight. Loosen the cable tension.huh?
03-28-07, 06:04 PM
Perhaps I wasn't clear enough... lol :)
As I understand it, you're having a hard time shifting to the big chainring. When you say 'tough' time shifting, that could mean a few things. Anyhow, if you mean 'tough' as in you physically have to push the shifter with force to get it into the top chainring, then that is a symptom of a shifter cable that is too tight.
Other reasons for not shifting to top chainring are:
- dirt cable housing; clean cables
- derailleur alignment; make sure cage is parallel to chainrings
- derailleur adjustment; loosen H gear screw
- crank bolt loose; crank/rings are not pushed onto Bottom Bracket all the way or chainrings angled
- Mismatched components; chain/rings/derailleur compatibility
Perhaps describe in greater detail so we can narrow down the reasons.
I hope this helps more than my previous post :) lol
I'm sorry, I'm not thinking. That's a top pull derailleur. with a bottom pull, the cable will pull it from underneath. Also, if your FD is too LOW on the mount, it will hit the top chain ring and not shift up. You want about .5 - 1.5 mm or so of clearance between the teeth of the chainring and the FD cage.
03-29-07, 05:35 AM
with the cable wrapped as shown in the first picture and all coasterx's tips followed, i still have to push incredibly hard when moving the cage up.
i learned on a atb review sight that this is a problem with this type of derailleur and plan on getting a pure top pull ( i think that is the right term ) one only.
until my new one is here i am keeping this one wedged open to maybe soften the coiled spring inside it.
03-30-07, 09:11 PM
END, i bought a new xt derailleur and have to take apart the chain to get it threw the cage.
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