FDwon't shift down
 

For some reason the FD no longer respond to my shifter. I shifted from the middle ring to the largest one. However once there, it won't shift down anymore. The STI shift lever to move the derailler to the smaller ring doesn't click either. Any ideas?

Does it shift down when you disconnect the cable? If so your shifter is broken.

That's what happened to mine, so I overhauled it.

http://www.bikeforums.net/showthread...-rebuild-guide

Pics coming soon.

If you're not game to disassemble it, I'm pretty sure it was just a matter of gummed-up grease... but I'd already tried to fix it by squirting WD40 at it, so you might have to get the lever off the body and soak it in degreaser or something.

Hose the shifter out with some finish line speed degreaser, ensure that the cables are all clean, not rusted or have their housings crimped somewhere. Make sure there is good cable tension, and that the limit screws are all in the proper places.

Bet it's the shifter. Has it been reluctant to downshift for a while, and been getting worse?

You should be able to easily check whether it's the shifter by applying extra tension to the exposed cable when trying to downshift. If it makes no difference, it's the shifter.

I think you are right. The down shift lever doesn't even click. In my other bike when the FD refuses to shift, at least the lever clicks.

Do you mean, loosening the cable? I might bring it to my LBS. It's still under warranty. But it would be real silly if it turns out to be some simple fix....

This problem is often fixed by squirting the shifters full of WD40. The factory grease gets hard with time, and dirt and corrosion can also add excess friction.

Al

But it's not like the shift lever is hard to shift or anything.

Doesn't matter, shoot it full of WD40.

1. Using the cable trim/tensioner loosen the cable until it's slack.
(If you can't get it slack, then the cable was bound to the FD while the shifter was not set for the small chain ring position. You'll have to disconnect the wire in this case. Go to step 2.)

2. Check to see if the shifter will shift up and down properly by holding the slack inner wire in your hand and applying tension to it. You'll feel the shifter pull for two shifts and release for two shifts, if the shifter is OK. Reconnect the wire to the FD while the shifter is in the position for the small chain ring if you disconnected it in step 1.

3. If the shifter is working, leave it in the position used for the small chain ring, then tighten up the inner wire using the trim/cable tensioner until there's no slack, but not overly tight. If the shifter is not working while the wire is loose, then see your LBS.

4. Try shifting up one position. If it works, leave it alone--you are [probably] done--try step 7. If it doesn't work, grab the inner wire and pull with enough tension to get to the center chain ring. Hold the wire in that position with one hand and with the other hand tighten up the trim/cable tensioner.

5. Shift back down to the small chain ring.

6. Redo step 4 and 5 until it shifts properly between those two positions.

7. Try shifting to all three chain rings. Use the same technique as in steps 4 and 5 to get all three shifts to work.

If none of the above works (or you just don't feel like futzing with it), go see your LBS.

Take the cable off the front derailleur before you go shooting WD 40 everywhere. Once you determine that it's your FD that's bunged up you can try and lube the pivots with some light oil and work it in, if that works then great. If not then you'll need a new derailleur and perhaps a front fender!

As for playing with the FD, this may come in handy for you. I wrote it. Feel free to make a copy if you like:

_____________________________________________________________________________________________

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.

Update: So I disconnected the cable to the FD. Shift lever clicks through fine. Looks like the cable was too tight?
Now I have to reattach the cable to the FD.

+1. I followed your steps in a previous thread. Starting from the very, very beginning = very good idea.

Phew.

But how does that happen by itself? Weird...

Indeed. I can only think of I did transport the bike in the trunk and it may have rubbed with other stuff in the trunk as well. But who knows...

It can happen- the cable gets caught on something or hung up on a bolt or the cable housing gets pulled out of a stop part way or something... unless you're very familiar with cable routing it can be easy to miss.