Frame flex is reasonably unlikely to be the culprit on most bicycles. There are a few points to check -
- Rear Derailleur Hanger. These get bent and twisted. For friction systems, the twisting is more of the issue, as it puts the guide (upper) pulley out of line with the chain path. Essentially, this tries to tease the chain to the next sprocket even when everything is correctly positioned. - Modern sprocket (cog) sets. It is reasonably difficult to find a cogset which is not designed to easily assist in shifting. That's how the all-in-one type indexing works - those little ramps and cut-downs on the teeth and sprockets. Add a little road grit or globs of mud and it "adds" another ramp. In generally, the teeth also tend to be shorter than old-tyme freewheel sprockets. They are also reasonably thin and in my experience, wear down faster. - Excessive guide pulley play. Again - part of the system these days. This play allows a dumb system - i.e. any indexed system - to adapt to slight changes in position by adding imprecision at the cogs. Good if you are stacking 11 sprockets on the wheel and want to use indexing, but a challenge if you want to manually shift. I have swapped guide and jockey (tension) pulleys to good effect. - Cables, tips, housing. This should probably have been number one. All sorts of variables here - crimped housing, ends/tips out of round and hanging the cable, grit in the housing, too big or small of a loop at the rear derailleur. Best cheap gift you can give your bicycle is a new set of cables and housing. - Shifter Bits - washers get compressed, and when you are using tension to hold things in place, you can simply squeeze things too tightly for too long. I know when I have a little imprecision in shifting, the first thing I do is honk down on the thumbscrew. Easy to go a 1/4 turn when an 1/8 will do. Hope that helps, - Jim / cyclofiend.com On Friday, March 8, 2013 9:44:03 AM UTC-8, ColonelJLloyd wrote: > > That's correct. I have trouble with my Simplex Retrofrictions slipping > when climbing. I assume this is due to a combination of a very strong rear > derailleur spring and frame flex. > > On Friday, March 8, 2013 11:30:05 AM UTC-5, Michael wrote: >> >> Looks like a mini-ratchetting system. Like micro-indexing or something. >> >> So I am guessing that when you shift gears, the ratchet mechanism holds >> the derailer in place over the cog so you will not have the chain slip off >> if it isn't a perfect shift, like what happens in pure friction shifting? >> >> That would be a nice improvement over friction, as I have had the chain >> drop to higher gear when standing. Ouch!! >> > -- 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 http://groups.google.com/group/rbw-owners-bunch?hl=en-US. For more options, visit https://groups.google.com/groups/opt_out.
