Help: Campy Record Triple/10 speed Chain Skip/ Jump Problem

I'm new to the Campy Record 10 speed world. I have a newly built Moots road bike with Campy triple
(30, 39, 53) and 11-23 cassette. Under load, the bike performs flawlessly when in the smallest chain
ring. When in the middle chain ring and in the middle of the cassette, the chain either skips (but
stays on the cog) or jumps to the inside chainring or completely off. Again, this only happens under
load (sprinting/Climbing). Since the frame and parts are all new, I'll trust that frame alignment is
not an issue. The derailleur hanger appears to be aligned. When in the largest chainring and
smallest cog, the rear-derailleur bottom jockey wheel is pulled slightly forward out of perfect
vertical alignment with the upper jockey wheel. Derailleur adjustment seems to be spot on. Do you
have any insights into what the problem could be? This is a very un-nerving and unsafe situation as
I don't feel comfortable getting out of the saddle and torqueing up a hill when in the middle
chainring for fear of the chain jumping off.

 

relatively amateur opinions:

1) sure cage of front derailleur is not nudging the chain?
2) is chain too short?
3) crankset loose on BB spindle -or- (drum roll, this happened to me)
4) loose chainring bolts allowing chainring to move sideways
5) bent chainring ( could happen in shipping or when you weren't with bike)
6) BB loose or just bad chain line?

 

Which length of rear mech cage are you using? The short one will not cope with the slack caused by
the 30/53 front combo and the medium and long arm mechs will not cope with a smallest sprocket of
less than 12 and 13 respectively. It may be that you are running the chain too tight or loose to
compensate for these limitations and that is causing the jumping.

 

rs-<< Which length of rear mech cage are you using? The short one will not cope with the slack
caused by the 30/53 front combo and the medium and long arm mechs will not cope with a smallest
sprocket of less than 12 and 13 respectively. >><BR><BR>

Not in my experience. If the chain length is proper for the components use, this isn't a
problem...like using an 11t with a long cage for instance, regradless of what Campag says...

We put long cage triples with 12-25 all the time with the possibility that the customer may want a
13-26 or 29-no problema...

Peter Chisholm Vecchio's Bicicletteria 1833 Pearl St. Boulder, CO, 80302
(303)440-3535 http://www.vecchios.com "Ruote convenzionali costruite eccezionalmente bene"