Your derailleur hanger is bent, you need a hanger alignment gauge to straighten it.
RECAR77 on
I can only see the rear derailleur or derailleur hanger being an issue. it’s easy to test the hanger with an hanger alignment gauge but since modern shimano derailleur cage plates aren’t parallel or flat anymore it is kind of hard to tell if they are bent/twisted or not.
Assuming the hanger is straight I would get the derailleur replaced under warranty and if that isn’t an option I would get two parallel pliers/channel locks or equivalent, hold the cage right below the guide pulley with one set of pliers (so that it is held in position) and then twist the cage by the tension pulley carefully so that the tension pulley points more to the chainring (instead of pointing inwards)
MGTS on
Adjust your B-limit, check hanger alignment
CargoPile1314 on
Your initial premise of “everything’s perfect” in the first gear you showed us in incorrect, IMO. There are sounds occurring a couple times between 0:16 and 0:19 that suggest the chain is not riding cleanly on all of the gear teeth it is passing over.
That it gets worse with increased chainline angle on forward pedaling and improves when backpedaling on the same gear suggests the problem is some combination of bent and/or twisted derailleur hanger and/or cage (IME, more twisted than bent if no other adjustments were made and it still shifts properly gear-to-gear and the derailleur is in the right spot on the high limit).
bikefidelity on
Doesn’t look like a ‘new’ deraileur imho. Make sure that your pulleys were correctly mounted. They are directional (little arrows) and should spin freely.
SiWalder252 on
If that is a shimano 12 speed derailleur, the cage is supposed to flare outwards slightly. Yours looks completely straight so that’ll either be a bent derailleur hanger or bent cage.
Being that it’s a new derailleur my bet is on the hanger.
Before bending or ordering a new hanger, I’d be tempted to double check that your current one is seated/installed properly just on the unlikely off-chance that something snuck in between the frame and hanger the last time it was installed.
7 Comments
Your derailleur hanger is bent, you need a hanger alignment gauge to straighten it.
I can only see the rear derailleur or derailleur hanger being an issue. it’s easy to test the hanger with an hanger alignment gauge but since modern shimano derailleur cage plates aren’t parallel or flat anymore it is kind of hard to tell if they are bent/twisted or not.
Assuming the hanger is straight I would get the derailleur replaced under warranty and if that isn’t an option I would get two parallel pliers/channel locks or equivalent, hold the cage right below the guide pulley with one set of pliers (so that it is held in position) and then twist the cage by the tension pulley carefully so that the tension pulley points more to the chainring (instead of pointing inwards)
Adjust your B-limit, check hanger alignment
Your initial premise of “everything’s perfect” in the first gear you showed us in incorrect, IMO. There are sounds occurring a couple times between 0:16 and 0:19 that suggest the chain is not riding cleanly on all of the gear teeth it is passing over.
That it gets worse with increased chainline angle on forward pedaling and improves when backpedaling on the same gear suggests the problem is some combination of bent and/or twisted derailleur hanger and/or cage (IME, more twisted than bent if no other adjustments were made and it still shifts properly gear-to-gear and the derailleur is in the right spot on the high limit).
Doesn’t look like a ‘new’ deraileur imho. Make sure that your pulleys were correctly mounted. They are directional (little arrows) and should spin freely.
If that is a shimano 12 speed derailleur, the cage is supposed to flare outwards slightly. Yours looks completely straight so that’ll either be a bent derailleur hanger or bent cage.
Being that it’s a new derailleur my bet is on the hanger.
Before bending or ordering a new hanger, I’d be tempted to double check that your current one is seated/installed properly just on the unlikely off-chance that something snuck in between the frame and hanger the last time it was installed.
Make sure the wheel is seated in the dropouts.
Check der. hanger with a gauge.