Newbie has question: Why did my Rear Derailleur Bracket wear this way ?
01-03-22, 09:13 AM
#1
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Newbie has question: Why did my Rear Derailleur Bracket wear this way ?
Hello. I am new to Bicycling Repair. I have a Giant Mountain Bike with a Shimano RD M3000 Long Cage Rear Derailleur.
Can anyone explain why the Derailleur Bracket wore this way?
Thank you in Advance
The yellow arrow points to a notch worn by the chain
Can anyone explain why the Derailleur Bracket wore this way?
Thank you in Advance
The yellow arrow points to a notch worn by the chain
01-03-22, 09:20 AM
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In that big/big combo, something is keeping your jockey wheel to far from the cassette. You chain if it's not continuously rubbing that tab is at least too close to it and slapping it too much. Or is it just on the wrong side of the tab entirely? I'm having trouble deciding since the DR has several wonky things going on.
Do you have the b screw too far in? The jockey wheel should be much closer to the gears. At least mine always are.
Do you have the b screw too far in? The jockey wheel should be much closer to the gears. At least mine always are.
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01-03-22, 09:32 AM
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That was my first thought. Bet the chain clattered a whole bunch.
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01-03-22, 10:13 AM
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Oooops....
01-03-22, 10:23 AM
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In that big/big combo, something is keeping your jockey wheel to far from the cassette. You chain if it's not continuously rubbing that tab is at least too close to it and slapping it too much. Or is it just on the wrong side of the tab entirely? I'm having trouble deciding since the DR has several wonky things going on.
Do you have the b screw too far in? The jockey wheel should be much closer to the gears. At least mine always are.
Do you have the b screw too far in? The jockey wheel should be much closer to the gears. At least mine always are.
01-03-22, 10:24 AM
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01-03-22, 10:25 AM
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You can solve the issue by routing the chain correctly on the original derailleur. The B screw isn't the problem
Last edited by alcjphil; 01-03-22 at 10:32 AM.
01-03-22, 11:15 AM
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https://si.shimano.com/api/publish/s...001-06-ENG.pdf
https://si.shimano.com/api/publish/s...001-24-ENG.pdf
Go here and put in the model of your shifters. The DM for them might be a little more detail for adjusting the shifting than the General DM linked above.
https://si.shimano.com/#/
At any rate, if the chain was regularly touching that tab, then that was your problem. You had it routed wrong. But your tab is on the backside of the DR and not the front side as mine is. So I'm really not certain from your pictures. But if you put the new DR on, and it touches any tab then you know it ain't right.
01-03-22, 11:21 AM
#10
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Go look at a bike you haven't messed with for correct chain routing.
01-03-22, 10:52 PM
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01-04-22, 12:56 AM
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Nice to know that we were correct, can you explain how you figured that out? I only ask because I have been wrong in the past when I offered an opinion
Last edited by alcjphil; 01-04-22 at 01:01 AM.
01-04-22, 01:38 AM
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I’ve often wondered what the function of that tab is.
Does the tab have any purpose for the guiding/keeping the chain in the cage? I’ve never seen any marks on RD cage plate tabs.
Or, is it just to add stiffness to the cage plate?
John
Does the tab have any purpose for the guiding/keeping the chain in the cage? I’ve never seen any marks on RD cage plate tabs.
Or, is it just to add stiffness to the cage plate?
John
01-04-22, 04:20 AM
#15
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Very easy to do. I bought a new bike where the chain had been placed the wrong side of the tab. It took me ages to work out why I seemed to have this curious vibration, more noticeable in some gears than others. I was pretty unimpressed!
01-04-22, 06:30 AM
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Looks like you now can just have it on the shelf for that someday you might actually need to replace the old one. Or replace it and keep the old one as a backup.
01-04-22, 06:32 AM
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The one function of that tab is to prevent the chain's coming off the tensioner wheel during shifts or while riding on rough surfaces. The longer the derailleur cage, the more likely the chain is to bounce off the tensioner wheel.
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01-04-22, 11:22 AM
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It happens. Shimano has even swapped the tab around on some derailers so that if you route it the “right” way, it’s wrong. Damn Shimano!
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01-04-22, 11:27 AM
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01-05-22, 12:19 AM
#20
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I wish I was 30 again & 5 hours of sleep a night was ok.
I would have more time to tinker with bikes.
All I can do is muddle through because house repairs &keeping the family cars running gets first priority.
Last edited by AJW2W11E; 01-05-22 at 12:51 AM.
01-06-22, 10:05 AM
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I personally would have a longer cable housing from the boss on the chain stay to the rear derailleur, looks stretched.
01-06-22, 06:03 PM
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Good eye. It is a bit short. Shouldn’t have a kink in it like that.
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Plan Epsilon Around Lake Michigan in the era of Covid
Old School…When It Wasn’t Ancient bikepacking
Gold Fever Three days of dirt in Colorado
Pokin' around the Poconos A cold ride around Lake Erie
Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
Stuart Black
Plan Epsilon Around Lake Michigan in the era of Covid
Old School…When It Wasn’t Ancient bikepacking
Gold Fever Three days of dirt in Colorado
Pokin' around the Poconos A cold ride around Lake Erie
Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
01-06-22, 06:41 PM
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Whats embarrassing is I still can't see it... Rats!!!
Kinda like when the Grand Babies bring over those picture puzzles where you find a hidden item... Ha
Kinda like when the Grand Babies bring over those picture puzzles where you find a hidden item... Ha
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01-06-22, 07:05 PM
#24
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Thanks I replaced the whole cable and I retuned the entire rear and...then I remembered how bad the front derailleur was shifting and I ordered the parts to fix that..only because of you guys on this Forum. Figured you guys were watching me down in the garage.
Last edited by AJW2W11E; 01-06-22 at 09:59 PM.
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01-07-22, 03:26 PM
#25
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Oh these days 30 years old nets you a couple young children and you have no time to play with bikes at all 😀.
