I've been trying to follow the Parktools video on doing the Fr der adjustment. When I do the L screw adjustment, if I have the inner cage as close as possible to the chain and try shifting to large and back to small, the chain drops, which is the issue I'm trying to fix. The point of putting the cage as close as possible without rubbing is so that it prevents the chain from doing that. When I watch I see the chain being pulled further from the chainring because of the alignment with the large cog in the rear. Yet when I do it slowly without letting the outer cage push as far as possible it seems to work. If I adjust the screw so that it doesn't come off it rubs. It just seems that the outer cage pushing the chain and the cassette pulling it is not being restricted enough by the inner cage.

What should I try? The derailleur does seem to be high in the rear. Should I try to make the curve of the cage more parallel to the rings? I'm not sure how much adjustment I have there.

My rear is well adjusted and shifts smoothly and silently, better than I thought possible, based on using the same guy's video from Park. (A plug for Parktools for making these videos.)

The derailleur is Chorus 10sp from about 10 years ago, the cables and housing are brand new Campy. The crank is an FSA 50/34 setup and the rear is 13/26, chain is Record 10sp. Both cassette and chain are new from about a month ago.

If I can get the front shifting correct I'd feel like I'm riding a new bike.

ALIGNMENT and HEIGHT of der. is correct?

and the der. cage should mimic the curve of the largest chain ring... if it doesn't, it's not the correct der. for the frame or chain ring size... sounds like a bit of both in your case... the 50 ring is niot that much smaller than the usual 52 or 53 on a fast road set, but i'm thinking the seart tube angle is kicked more rearward than what the der. was designed for....

what brand/model is the frame?

set the der. cage 1mm above the large ring, btw... 1 to 3 mm is typical factory rec . setting... 1-2mm for some f. ders...

verify that the cage is EXACTLY aligned to the outer ring... use the INNER face of the der. for alignment, and that it remains aligned when you shift it! i had one that had been twisted in such a way that it changed alignment.... and i've seen cages that were pinched inwards, and a few that had been pulled wider, too! yours is most likely pinched, if bent at all...

I'll add that you are asking the system to front shift is the worst configuration possible.


The der cage and large ring gap is not uncommon for the years ago this was made. Many ft ders were the same for standard rings (52, 53T) as for compact ones for a while (early on in the compact era). So the cage would "raise" above a 50T ring at it's rear end compared to the 53T ring. Yet many of these der/ring combos work well enough today still.


But it's an easy experiment to find out, just lower the der and see


My initial take is to not use the big big combo and not be worried about how the shifting is when in this combo. Andy

Worn chainrings so that new chain doesn't drop onto teeth well?

Derailler too high? Cage should be very close above large chainring teeth.

The height of the front of the cage against the large ring is maybe 1mm. It doesn't touch but just barely. The back of the cage is raised though. I'll try to get this aligned.

The frame is a 2006 Kuota Kredo, not a common one. If anything the seat tube is more upright.

The big/big combo is what the video says to try, not to use it but for testing the shifting as that's the extreme. I've had an instance where I was going up a hill in the big/big and then shifted and the chain dropped. Since I was going uphill, I lost all momentum and couldn't unclip and joined club tombay. This is the situation I'm trying to fix. It isn't good practice I know to be in big/big, but when you are and you shift it should still work. Everything else works. At least here in NYC I'm almost never on the small ring anyway. There aren't all that many hills here to climb and mostly I stay on the big ring on the few that I do.

Chainrings are actually recent and not worn, but aren't brand new either.

After I posted I tried multiple times and it worked with the bike on the trainer, but that doesn't mean it'll work on the road. I think I'll try to make the curve match the chainring better.

You should ditch the compact crank for a proper one; compact cranks suck. The 14t gap not only makes for the sort of hassles you're experiencing, but also means there's little overlap in your ratios, which might sound good, but makes for otherwise unnecessary front shifts, right at the speed you're doing most often, at least on a nice tight cassette.

And with the ratios you're running, as you say, the small ring is almost useless.

If you're going to stick with the compact, you might be able to get an angled shim to go behind the hanger if it's a braze-on, which might sort it, otherwise you'll have to settle for a chain catcher.

The bike is over 10 years old at this point so I'm not changing anything with it anymore. And the rider is also getting old, 63, so I'm not going to want higher gearing. It was originally 50/36, but I changed it to 50/34 so I could climb Mt. Haleakala, which is actually a 16t difference, and maybe that's part of it.

I didn't go back to it last night after my last post, so I'm not so sure that I don't have some leeway, and I will check this out. Even if I can't get the circles to line up, I can try to make it the best it'll go. And since it was shifting OK maybe that last tweak will be enough to ensure it doesn't drop.

FDs are more of a PITA than the rears.

Agree that the most common setup is to have the outer cage parallel with the chainrings. However, Sheldon Brown does note that

"Rotating the (front) derailer so that the back of the cage is farther out will sometimes improve shifting to the small ring of a triple by preventing overshifting, but may cause increased need for trimming on the larger rings. It may also cause the crank to strike the cage. Rotating the derailer so that the back of the cage is farther in will help reduce the need for trimming on the large chainwheel, and will provide crisper downshifting, but with a greater tendency to overshift on the inside. This may be appropriate on bicycles equipped with an anti-derailment device.

You can llso install a chain catcher (there are lots out there). No derailleur adjustment needed.

Here's an odd one that I've found a time or two: Try loosening the high limit screw about 1/8 turn.

Some bike mechanics adjust the high limit screw by putting the chain onto the big ring and tightening the limit screw down against it. My theory is that makes the limit screw act like a lock nut. It delays the shift just a slosh and, when it finally releases the derailleur cage, throws the chain across the small chain ring.

Probably going to take some hits on this from the technical book guys but I've had it work on more than one bike in real life.

Or problem index compatibility?

I finally had a chance to check this again. I took the derailleur body off the post, and then adjusted the post on the frame so that it would rotate as far as possible in the right direction. I remounted the body and now it is much closer to the rings all around. You can kind of see that it was made for a 53 instead of a 50, but it isn't off by much.

In any case, the shifting is better now, it hasn't dropped yet. I still need to readjust the limit screws, but that would be it. It is a double so no fussing with cable tension, plus it is Campy, so I have fine adjust at the lever. The one time I rode an Ultegra bike I hated the fact it didn't have any trim, and my MTB is Deore and it also doesn't have trim. Maybe the newer Shimano stuff is better that way.

Thanks for the help. I think the real answer was twisting the cage so that it lined up.