Automatic shifting up front......?

[Lewis Moon]

I have functionally new Record 11 shifters with a pretty new Chorus front derailleur on my Masi 3V and it's shifting down when I get out of the saddle. Every time. Stoplights, hills, sprints. This is the second set of Campy shifters this has happened on. Same frame, different shifters. AND... when I moved the shifters to a different frame the down shifting stopped. What the heck is happening?

[sitzmark]

Tight tolerance on FD and frame flex?

[Lewis Moon]

Originally Posted by sitzmark

Tight tolerance on FD and frame flex?

At 6'4" and 200 lbs I may be a bit big for the 3V. The other two bikes that I have no problem on are both Ritchey framed.... With the ovalized seat tubes.

[Lewis Moon]

Anyone have an idea of a way to stop this? I REALLY love this bike. It's the best handling bike I have ever ridden but the shifting issue is enough of a problem to really piss me off.

[SPOKE]

Just maybe you may need to put another inch or so of cable housing between the brifter and down tube cable stop.

[Lewis Moon]

Originally Posted by SPOKE

Just maybe you may need to put another inch or so of cable housing between the brifter and down tube cable stop.

How might that help?

[sitzmark]

Not sure I understand - does the FD actually shift or is the chain dropping on its own?

Have you tried running it without an FD to eliminate FD as cause of derailment? Bent/irregular toothed ring possibly? Loose chain ring bolt(s)? BB square to chainline? Chain binding under load and not releasing properly?

Sounds like something crank-base moves out of alignment under load.

[Lewis Moon]

Nah, it shifts at the brifter. I'm pretty scrupulous about clicking it back up before the chain drops. What I think is happening is that flex in the BB is causing more tension on the cable and it is kind of "ratcheting" on where it goes under the shell. I greased the cable there but nothing is helping.

[sitzmark]

Only thing I got then is to check the limit screw. Might be set so FD/brifter can’t fully lock into place and pops out when system is under load.

Good luck - hope you get it sorted!

[bigbill]

I had this and it was related to how much travel the FD had with relation to the shift point. I was right on the edge of the index when I was on the big ring so if I touched the thumb paddle a little hard, like when leaving an intersection, it would drop to the small ring. I adjusted the travel of the FD so the shift point required a purposeful downward movement of the paddle instead of acting like a trigger.

[Ralph]

Originally Posted by sitzmark

Only thing I got then is to check the limit screw. Might be set so FD/brifter can’t fully lock into place and pops out when system is under load.

Good luck - hope you get it sorted!

All I can think of also. Give it 1/8 turn and see if that does anything. You may need to give it some cable also.

[Lewis Moon]

This makes sense. I'll try it. Thanks.

[bikinchris]

My guess?
One of your springs in the shifter that index the ring are broken. I call them q shaped springs and there are two in the shifter. When you stand up, the flex in the frame allows it to shift by pulling on the cable. When both springs are in good shape, it is fine. When they are worn or one is broken, it just barely holds the ring inside the shifter and it will let go.

[dddd]

I'll be the 3rd or 4th voice here (sitzmark was 1st) to say that a check of the hi limit screw is in order.

When in hi gear, actuate the shift lever, and the derailer should move a little bit out past where it is resting at it's indexed hi-gear position, and should then move back slightly when you release the lever.

The same is true at the rear derailer, only there it's the lo-limit screw, and the overshift movement should be minimal (as to be difficult to discern visually) or you risk the chain overshifting into the spokes.

On bikes with ratcheted shift levers, i.e. Shimano and SRAM, a too-tight limit screw is a most common cause of premature cable failure as well as generally shorter adjustment service intervals. Most of Campy's levers are indexed using a two-way detent (like a downtube lever), instead of an actual ratchet that holds position against any tugs on the cable caused by frame flex.

[SPOKE]

Originally Posted by Lewis Moon

How might that help?

It should give the cable & housing a little more flex or slack that may counter any frame flex that may be creating the ghost shifting. All this is dependent on the shifter working correctly.