I’ve been working on swapping parts from my carbon bike to a Centurion Ironman frame. The swap is complete but I’ve been dealing with an adjustment problem that I have not been able to resolve. When the bike is in the stand, the front derailer will shift from the small chainring to the large chainring in a satisfactory way (i.e the shift is quick and crisp). When under load, however, the shift can no longer be completed (the front derailer reaches the same position as it did when not under load, but the chain does not make it to the large chainring—it won’t catch). The only way to adjust the front derailer to complete a shift is to further increase cable tension (already pretty high) and loosen the outboard adjustment screw. When in the stand, this will throw the chain, but when under load the upshift can be completed.
The problem is that this “fix” has the front derailer too far outboard and gives me far fewer usable gear combinations. One of my co-workers (I work at a shop) took a look and was stumped too. Is there a reason why the chain might not be “catching” onto the large chainring while under load? Anyone think this is compatibility issue with the parts I’m using?
Here’s the component spec:
FD: 105 (FD-5600)
RD: Ultegra short cage
Cassette: 105 11-23
Chain 105 (CN-5600)
Shifters: 105 (ST-5600, the earlier double/triple model)
Crankset/BB: Truvativ Elita 50-36 w/ GXP; for 68mm BB shell (not a 50-34 as previously stated)