Bicycle Mechanics - slipping chorus 8 speed

i have a colnago fitted with campag chorus 8 speed groupset,when under load it drops a gear (really annoying) ive had the cassette and chain changed but it stiil happens any idea

barrel adjuster?

Ask Tim at www.branfordbike.com He is probably the largest on-line seller of Campy parts and is very helpful/knowledgeable. You might also ask at www.campyonly.com Again, helpful/knowledgeable folks there.

Check your "drop-out" alignment. If your drop out is straight and the derailleur isn't bent. The cage should line up with the bottom pulley slightly "outboard" of the top pulley, it's best if you have your LBS stick an alignment toll/gauge on it. Have your shifter, (in brake), checked for loose or worn parts. Replace your derailleur if it's getting "sloppy", it's sloppy if you can move the cage from side to side very far or easily with your hand. Check your cable housing for fraying at the ends and the caps for wear, you may need to replace both. The caps may be letting loose parts/(cables) in the housing or the housing itself push/shift beyond where it's/they're supposed to stop. The caps may be for brake housing and not for derailleur housing. The cap ends for brake housing are flat, cable housing cap ends are curved to form a trough on the inside to hold the housing end more securely

Ride Steady
Pat

One of the nicest things about Campy (compared to Shimano) is that any worn parts can be replaced. If the derailleur is worn, it can be rebuilt and doesn't require replacement. Just read a letter from Shimano in response to a question in the Tech Q&A on Velonews telling someone who had a broken return spring in their DuraAce STI shifter that it can't be repaired but must purhcase a new shifter. Great design, until a 50 cent part needs replacing.