Other than commuting this week, haven't ridden since Foxy's. The Quantum Pro had quite a few shifting problems there and today it was even worse. I have been racking my brain trying to figure out what's going on. The chain skips and tries to change gears with annoying frequency and especially under high torque (sprints, climbing). It happens less in the big ring and at the outside edges of the cassette but today I could scarcely keep it in any gear anywhere. Putting on a new chain and cassette a month ago didn't seem to help at all and I have futzed with the cable adjusters to no success either. So while I'm hobbling up the mountain I come up with another couple possibilities I could check out when I get home - my new chain might be a link too long (doubtful but I'm desperate) or my B-screw might let me get my jockey pulley a little closer to the cogs; the other options were a crack in the derailleur, bent axle, or tweaked alignment on the hanger.
So I caressed the crippled cruiser to the cross-roads and cursed. Time to get serious about this issue.
Could have kicked some poser booty on the Dips but I was afraid I'd pass him and then have to slow down again with a chain problem so I held back.
Back at home I set up the workstand and inspected all the suspect bits and played with the B-screw but I wasn't finding the AHA problem. Until I noticed a slight chainskip that looked at first like a stiff link but upon closer investigation turned out to be a chain pin that was sticking out. That was the first thing that made me think I might have it - the pin would be causing the pickup ramps on the smaller cogwheel to snag and initiate an upshift.