Try turning the cable adjuster at the derailleur a couple or three clicks clockwise (as you look down it toward the derailleur). Does that make it so that shifts to a higher gear (smaller sprocket) go smoothly but shifts to a lower gear (bigger sprocket) are unsmooth and require overshifting to get the chain to climb up to the bigger cog? That's how shifting is on my tandem--no hesitation shifting to smaller cogs, some hesitation requiring a slight-bit of overshifting to get to bigger cogs, but once you let go of the shift lever the chain stays on the bigger cog and won't "ghost shift" to a smaller cog.
On Tuesday, June 21, 2016 at 7:32:28 PM UTC-4, Michael Hechmer wrote: > > To be clear. The index shifting lifts the chain from 11 to 28 very > successfully, but when I try to drop the change from the 28 to the 24 and > then to a 21 it hangs up and then jumps cogs. > > I intend to disconnect the derailler and slide the rear cable housing > around looking for a hang up. However I will be surprised to find that is > the problem because I am pretty careful to both file the housing and open > it with an awl. > > My trip to my favorite mechanic yielded a number of suggestions: > Check the pulleys for side to side play and for ware. The former, > especially, will throw indexing out of whack. I did this and found no side > to side play but still need to get a new pair of pulleys out to look at the > difference. > Adjust the B screw. The closed position may actually be too tight. This > too does not seem to be the problem. > My cassette does not need replacing. > Use a Shimano chain. I think it is unlikely that a Connex 9 spd chain > works less well than a Shimano. > The shifter itself may be worn. If it's really bad you can feel it, but > it seems to me that it is very possible that one part of the shifter is > worn enough to throw everything else out of alignment. > We agreed that the length of the cable (I actually have three cables, with > a splitter at each S&S coupler to simplify disassembly) stretches the > limits of friction shifting. > > I intend to road test the system but it increasingly looks like I will > find it easier to stay with friction. I think I have a little room to move > from a 48 to a 50 ring without needing to change the derailler, cassette, > or shifters. > > I hope I am not discouraging anyone from trying a tandem; they are great > fun in spite of the extra challenges. > > Michael > > On Tuesday, June 21, 2016 at 5:06:53 PM UTC-4, Bill Lindsay wrote: >> >> In my humble opinion, NickBull is on the right track. The symptoms >> described are 100% consistent with this description >> >> On Tuesday, June 21, 2016 at 1:44:42 PM UTC-7, NickBull wrote: >>> >>> My stoker and I have ridden over 11,000 miles (mostly randonneuring >>> miles in hilly/mountainous terrain) with 9-speed indexed (bar-end) shifting >>> (Deore RD), a Sugino 24/36/48 crankset and SRam 11x34 cassette. The 48-11 >>> combo is high enough, once you get over 30 miles an hour you may as well >>> tuck. The 24-34 is low enough for almost any grade you'll encounter. I >>> never have problems with downshifts, but for upshifts have to shift >>> slightly past the "click" wait until I hear/feel that the derailleur has >>> shifted then let the shift lever fall back to the click. I suspect that >>> you may have some cable drag, but it may also be that you've optimized the >>> shifting for upshifts and that's making it "hang" on the downshifts. >>> >>> Nick >>> >>> >>> -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To unsubscribe from this group and stop receiving emails from it, send an email to rbw-owners-bunch+unsubscr...@googlegroups.com. To post to this group, send email to rbw-owners-bunch@googlegroups.com. Visit this group at https://groups.google.com/group/rbw-owners-bunch. For more options, visit https://groups.google.com/d/optout.
