FD woes

smacl

I've an old triple on the front of my bike, a Campag Xenon 52/42/30. It seems to have real problems dropping from the middle ring into the granny ring with any pressure on the chain. So if I'm going up a hill, I really have to drop into the small ring very early or not at all. I've checked the deraileur adjustment and limit screws, and set it up on the turbo trainer. With the brake off, the shifting is perfect. With the brake on, it struggles and I need a fast loose cadence to drop into the low ring. I'm pretty sure it's not the lower limit screw, as if I loosen it any further, the chain is prone to falling off altogether. I don't think it's the cable tension, as I have tried it all the way back to lightly slack in the small ring which gives the deraileur spring the minimum resistance. I've recently replaced the chain (and cassette), and cables. The FD height is as low as it can be to clear the big ring.

My guess is the FD and/or middle chain ring is simply worn out and need replacing. Any idea which of these it is more likely to be, and if it is the FD needs replacing, any idea what would be a suitable replacement? The chain rings are 130mm BCD FSA, so more like shimano than campag, and I reckon this will work as a replacement. Less sure about a replacement FD, even after reading Sheldon, any advice appreciated.

bcmf

My money is on cable trension. Get a new cable and housing and reset the whole lot. It sounds like your cable isnt moving freely in the housing and isnt letting the fd drop as it should.

smacl

bcmf wrote: »

My money is on cable trension. Get a new cable and housing and reset the whole lot. It sounds like your cable isnt moving freely in the housing and isnt letting the fd drop as it should.

Not so sure. I've already replaced the cable inner and outers, and the cable is slack in the granny ring. After looking at it again, I'm beginning to think it may be that the spring in the FD isn't as strong as it once was, and doesn't have the strength to push the chain off the middle ring when under tension. Works fine when there's no tension on the chain, as per the many FD adjustment videos on youtube. I've tried cleaning the spring, in case a build up of grit/crap is impeding it, and while it's helped a bit, the shifting is still pretty crap. Might see if I can source a spare 9sp triple road FD.

Edit: This looks like it might do the business.

bcmf

smacl wrote: »

the cable is slack in the granny ring.

There is your problem me thinks. You really should have no slack on the cable!

Put in the granny front and hit the thumb shifter (presume you are using campy shifters) all the way till there are no more clicks.
Get a pliers or something to hold and pull the cable.
Undo the lock bolt and pull as much tension outta the cable as you can and re do the lock nut nice and tight.
Then try your shifting. It may need tweaking but you can use your barrel adjuster/down tube adjuster to do it.
Since you have been playing with your limit screws they may need to be sorted as well.

Holyboy

I would guess it be one of two problems, either you haven't clamped the cable in the right way on the mech or the more likely cause is the outer plate of the mech has bent out wards over time so the space between the inner and outer plates is too wide, it happens a lot with Shimano front mechs, not as much with Campag' but I have seen it over the years.
You can bend it back into shape with something like a slipjoint pliers, it sounds very crude but there isn't really any other way of doing it.

smacl

Thanks for the replies guys, and interesting to see that neither of you reckon it is the spring. Most other forums I've scanned also concur that the problem is rarely the FD, though I've tried a variety of cable positions from quite tight to quite slack.

BCMF, reason I don't think it is the cable is that the cable tension seems to be used for moving up to a larger ring and preventing the FD going past the desired ring but I don't see how it actually assists in moving the chain to a smaller ring, which seems to be the job of the spring. The fact that gear changing is smooth when there is no tension on the chain suggests to me that there isn't enough strength in the spring to do the job properly when dealing with some resistance.

Holyboy, thanks for the response it prompted me to look at the plates some more. In the inside of the plates / parallelogram, there is a pressed in section on the deraileur that has become flattened in at the location it contacts the chain when dropping down from the middle ring. Excuse the grotty photo. I'm guessing the down shifting depends on this, and is not happening due to wear. I'm going to try raising the FD by a small amount to change the contact area to bit that is not worn. (I can't lower it as it barely clears the big ring already). If this works, it'll probably means I need a new FD in the medium term.

In terms of compatibility, any idea what would be a workable replacement. I'm guessing any campag triple that will take a 53 outer ring should work, given the distance between chain rings still the same.

smacl

Holyboy wrote: »

You can bend it back into shape with something like a slipjoint pliers, it sounds very crude but there isn't really any other way of doing it.

Took it off and compressed the offending section very gingerly in a padded vice. Put it back on, readjusted everything, and hey presto it works. Fully expected to make a total balls of it, so quite chuffed. It'll be interesting to see how she behaves over the next couple of weeks; a few long spins planned so fingers crossed.

Thanks again for the pointers.

smacl

Squashing the cage helped for a while but still problematic. Replaced the FD with a new Campag comp triple last night, which seems to work a treat. Talking to a friend at the Orwell Randonee last week who also had a campag triple said he'd had the same problem, so FWIW the Campag comp triple marked as 10 speed appears to be fine as a direct replacement for the 9sp with 53t big ring. Changing front gears seemed pretty crisp testing on the turbo last night, I'll take her out in the hills over the weekend to confirm.