Originally Posted by
Ygduf
unlikely to be the cause, but I had those exact symptoms when my cable was super gummed up with sports drink and sweat and road grime where it went under the bottom bracket. Shifting small to big I was pulling in cable tension and it worked fine. Big to small, the cable tension was released and the derailleur spring had to really work against the gummy bits.
I've always wondered if that old timey cable routing on top of the bottom bracket that was used back in the 70's wasn't really a cleaner approach because it blocked some of the road grime (especially for the ones that had housing stops and ran through cable housing for that curve.
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Bikes: 1996 Eddy Merckx Titanium EX, 1989/90 Colnago Super(issimo?) Piu(?), 1990 Concorde Aquila(hit by car while riding), others in build queue "when I get the time"