Strange rear mech issue
This morning I installed a new mech hanger after my old one sheared off after a few knocks and bending it back had obviously considerably weakened it. It wasn't a catastrophic failure and the mech didn't go through the spokes - gently caught a couple of spokes when in the granny gear and broke off. Was at low speed so no damage. Anyway, the new one is installed and is adjusted (more or less) except for this one issue.
For some reason, the chain doesn't correctly sit in the bottom jockey wheel in the rear mech. It tends to jump out the teeth and sit 'outside' the jockey wheel, but remains sort-of in place due to the cage holding it in. The problem is worse when in a lower gear (larger cog at the back).
I've had 2 offs on this bike, on the delicate side, and in both cases bent the mech back. Is it possible that the cage has bent as well? Stupidly didn't take any photos. All I can say is when in the highest gear (50x11) the rear mech points ever so slightly inwards, so there is a slight curve in the chain as it straightens out when reaching the chainset.
For some reason, the chain doesn't correctly sit in the bottom jockey wheel in the rear mech. It tends to jump out the teeth and sit 'outside' the jockey wheel, but remains sort-of in place due to the cage holding it in. The problem is worse when in a lower gear (larger cog at the back).
I've had 2 offs on this bike, on the delicate side, and in both cases bent the mech back. Is it possible that the cage has bent as well? Stupidly didn't take any photos. All I can say is when in the highest gear (50x11) the rear mech points ever so slightly inwards, so there is a slight curve in the chain as it straightens out when reaching the chainset.
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Marin Nail Trail
Cotic Solaris
Can't see why the hanger wouldn't be straight as it's brand new from Halfords (for the Boardman), but it could be the mech which is bent.
Don't have a straightening tool as I've usually always done it by eye.
Thanks for the offer, but having learned the hard way I don't want to be bending it if at all possible. Would rather pony up for a new mech!
New hangers often need tweaking. For either of two reasons: the new hanger is slightly bent (not unheard of); the new hanger is straight as an arrow, but because of manufacturing tolerances, it actually needs to be a little bit bent to suit the frame (if a hanger is 1mm out, then shifting will suffer or you'll have noise from the drive train)... think how accurately a carbon dropout can be formed... to 1mm?
So check the hanger alignment.
Bikes: Donhou DSS4 Custom | Condor Italia RC | Gios Megalite | Dolan Preffisio | Giant Bowery '76
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How do I know if its the hanger or the mech which is bent?
If the mech is bent, then it'll be the cage. Sit it on a flat surface and check for daylight. The mech cage should be perfectly straight; the hanger may need to be a little bent to suit the dropout.
(I'll wager the mech itself is fine)
Bikes: Donhou DSS4 Custom | Condor Italia RC | Gios Megalite | Dolan Preffisio | Giant Bowery '76
Instagram: https://www.instagram.com/ben_h_ppcc/
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Marin Nail Trail
Cotic Solaris
Time for another new mech hanger and may play it safe with a new mech as well!
Marin Nail Trail
Cotic Solaris
Rule #9 // If you are out riding in bad weather, it means you are a badass. Period.
Rule #12 // The correct number of bikes to own is n+1.
Rule #42 // A bike race shall never be preceded with a swim and/or followed by a run.
The first one had taken a few knocks so I appreciate it may have been weakened. I am pretty annoyed about this one as it had barely covered 45 miles before shearing off, and it had been in 34x25 earlier in the day with no issues. I have since laid the mech down and the cage is a bit bowed so will get new one. Still pretty annoying and definitely feel like a ham fisted spanner monkey now
Went to this
then to this
then about 30 miles later my other bike snapped a spoke so had to walk. I did do a damn good job of replacing it though