Clipless in Coeur d'Alene
Join Date: Mar 2012
Location: Coeur d'Alene, Idaho
Bikes: Tandems: Calfee Dragonfly S&S, Fandango 29er Mtb; Singles: Specialized Tarmac SL4 S-Works, Specialized Stumpjumper FSR, plus other misc Road & Mtb.
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 84 Post(s)
^^^ As noted, that picture is from the Bicycle Quarterly article, not my install. I always mount my FD closer to the big ring, maybe 2-3mm gap max, so in effect I agree that the FD position in the photo is not optimal.
I've been looking at this a bit more and think my shifting looks more similar to this next photo (also from article linked above). My chain has more skew to the outside I believe because currently there are 1.2mm worth of spacers between the granny & big ring (used so that the chain completely clears the 130bcd chainring bolts). I believe this extra spacing exacerbates the issue by causing even more diagonal chain skew than in the picture below.:
On my 48/30 chainrings, the chain links do appear to be at the correct meshing points where you would expect it to fall between the ring teeth. However when the more extreme diagonal chain path is present, a newer chain cannot twist back enough to correctly settle between the teeth, hence it is riding on the tops of the teeth, twisted over.
I'm going to experiment further with reducing the granny spacers to .6mm and perhaps some other ring types, sizes and combos.
Last edited by twocicle; 04-28-14 at 02:40 PM.