J
Jeff Travis
Guest
Greetings --
I've discovered something curious about the indexed shifting on my
bike (Campag 10-speed), and am hoping someone can enlighten me.
In pursuit of cleaner shifting, I tried a new (to me) approach to
adjusting the rear derailleur shift wire tension. Here are the steps
I followed:
1. Remove chain.
2. Disconnect rear derailleur shift wire.
2. Verify proper alignment of derailleur hanger.
3. Verify outer limit screw set so that jockey pulley is directly
underneath smallest sprocket.
4. Verify inner limit screw set so that jockey pulley is very slightly
inboard of largest sprocket when the parallelogram is deformed to the
inner limit by hand.
5. Verify shifter control is set for smallest rear sprocket.
6. Using fourth hand tool, tension shift wire and reattach to
derailleur.
7. Verify jockey pulley is still directly under the smallest sprocket.
8. Using the shifter, shift the derailleur one click; verify jockey
pulley is directly under next-smallest sprocket; adjust shift wire
tension as necessary.
9. Using the shifter, shift the derailleur to the next-largest or
largest sprocket; check position of jockey pulley.
Now for the curious part. At this point the jockey pulley does not
line up directly underneath the selected sprocket, but slightly
outboard. So I've shifted over 8 (or 9) clicks starting from perfect
alignment on the smallest or next-smallest sprocket, and the alignment
is now not perfect.
It seems like if the tension is set to put the pulley directly under
the largest sprocket, you won't be able to shift onto the smaller
ones, and if it's set to put the pulley directly under the smaller
sprockets you won't get a clean shift onto the larger ones.
Can you explain why the shifter works this way? Can you describe how
to judge the correct shift wire tension using this approach?
Thanks much,
Jeff Travis
I've discovered something curious about the indexed shifting on my
bike (Campag 10-speed), and am hoping someone can enlighten me.
In pursuit of cleaner shifting, I tried a new (to me) approach to
adjusting the rear derailleur shift wire tension. Here are the steps
I followed:
1. Remove chain.
2. Disconnect rear derailleur shift wire.
2. Verify proper alignment of derailleur hanger.
3. Verify outer limit screw set so that jockey pulley is directly
underneath smallest sprocket.
4. Verify inner limit screw set so that jockey pulley is very slightly
inboard of largest sprocket when the parallelogram is deformed to the
inner limit by hand.
5. Verify shifter control is set for smallest rear sprocket.
6. Using fourth hand tool, tension shift wire and reattach to
derailleur.
7. Verify jockey pulley is still directly under the smallest sprocket.
8. Using the shifter, shift the derailleur one click; verify jockey
pulley is directly under next-smallest sprocket; adjust shift wire
tension as necessary.
9. Using the shifter, shift the derailleur to the next-largest or
largest sprocket; check position of jockey pulley.
Now for the curious part. At this point the jockey pulley does not
line up directly underneath the selected sprocket, but slightly
outboard. So I've shifted over 8 (or 9) clicks starting from perfect
alignment on the smallest or next-smallest sprocket, and the alignment
is now not perfect.
It seems like if the tension is set to put the pulley directly under
the largest sprocket, you won't be able to shift onto the smaller
ones, and if it's set to put the pulley directly under the smaller
sprockets you won't get a clean shift onto the larger ones.
Can you explain why the shifter works this way? Can you describe how
to judge the correct shift wire tension using this approach?
Thanks much,
Jeff Travis