SpongeDad

DA 7800 Front Derailleur. Installed new cable and wire. Now up shifting is very heavy; downshifting takes a lot of force to overcome the first trimming click (which then sends chain down to the 39 ring).

Other facts to consider: 1) once in position the cage rides very quietly; and 2) the vertical position of the FD relative to the 53 ring has not changed.


Thoughts oh great well spring of BF knowledge.

And I should note that I have now become my father (Mech. Eng.), who would take a perfectly good car on Friday, mess it up on Saturday, fix it on Sunday and repeat it the next weekend with the other car. As I kid, I did not understand this.

FBinNY 

Usually with symtoms like yours I suspect a cable friction problem. That goes double, since you've just replaced the cables, and made no other changes. Double check the cable routing for sources of binding, and if you don't find anything obvious, remove the cable from the FD and shift it against hand tension.

If it's still still feels stiff strip it and re-thread it from the shifter out, being sure to properly seat the head into the lever.

lowlife1975

hmmm... i would try the above or a simplier solution might be to just undo the cable and reattach it but making sure not to pull the cable so taut. i find that when i do this, shifting is "stickier" b/c there's less cable to pull on. use the barrel adjusters to tighten the slack quarter turn by quarter turn.

JonnyV

Bingo! This is exactly what I thought as well. Unless there is something wrong with your shifter or you're getting some crazy cable rub somewhere your cable is just a bit too tight. Shift the chain into the small ring/big cog. Loosen the bolt that secures the cable on the FD. Just pull it through so there's no slop in the cable, tighten the bolt, make any fine adjustments to the limiting screws and barrel adjusters (if you have them) and you're ready to roll. Good luck!
Jon

SpongeDad

Good advice all - but you give me too much credit. When I went back to loosen the cable to see if that would do the trick, I notice something. On all my other bikes, the cable wire is clamped on the inside edge of the bolt - but on this one I put the cable on the outside of the bolt. By changing that - which moves the wire about 2mm closer to the seattube - the leverage changes enough that shifting is fine again.

I'm going to write a post on all the stupid things I've done to my bikes.

FBinNY 

AAH! there's method in our madness.

We needed a way to get you to disconnect and reconsider how you clamped the wire, without insulting you or hurting your feelings by pointing out that you did it wrong.

Seriously, glad it turned out to be an easy fix.

lowlife1975

are you sure you're a mechanical engineer? hahah... j/k. we've all had our fair share of mental lapses when working on our bikes... its all a part of the learning curve. just be glad that yours didn't lead to a serious mechanical failure on the road or actual destruction of the part... that's when the mistakes really hurt!

SpongeDad

well, I guess I haven't become enough of my father to take on his mechanical skills, although I do enjoy fixing something when you get it to that point when it runs smoothly. Swapping all the cables and cleaning everything on my bike, including the hub, has it running like new (actually a lot quieter).