Hi, I’m working at a summer camp this summer and I’ve been tasked to take care of the bikes. While checking to see how they are one of the bikes was doing this and I’m not really sure what’s causing it and how to fix it. If anyone is able to help it would be greatly appreciated!
Question: what is causing this and how can I fix it?
byu/No_File_8684 inbikewrench
by No_File_8684
4 Comments
Stiff links in the chain perhaps?
A few potential things that could be causing this, check them out to see if any of them might be the culprit:
1. Derailer is out of alignment. Usually you can use one of the small finger screws or “trim adjuster“ on either the derailer, or on the shifter. (Knurled piece where cable housing meets derailleur or shifter) It depends on the models you’re using as to which end of the system the trim adjuster is located.
One other factor you might have a bent derailer hanger and if that’s the case, you should just look up stuff on YouTube on how to adjust that. It usually requires a special tool, but there’s some other ways to get it done.
2. Wrong chain. Like using a seven speed chain on a 10 speed driller, or something like that.
3. Chain alignment. Some derailer pulley wheels have narrow and wide teeth to sync up with the narrow and wide parts of the chain if your chain is off by one link, then the narrow part of the chain is hitting the wide part of the pulley wheel. That might require a bit more inspection, but if that is the case, this is probably the easiest thing to fix as you just push your derailleur down to give it slack and move the chain one link over
4. b-screw alignment. Look up stuff on YouTube about how to adjust the B screw alignment for your specific derailer. The B screw alignment moves the derailer pull closer or farther away from the cassette cog. If your pulleys are too close to the cassette cog as you try to shift, they may be hitting One of the larger sprockets in the cassette, and that could be causing something like this as well. So check that out too.
It looks as though there’s a couple of links that are causing the jumping. You can see the occasional link skip above where everything else is moved along the jockey wheel. It could be due to a quick link not being fully engaged, making the rollers too close together and not fitting teeth of jockey wheel. Or there is an issue preventing correct articulation of the chain. Or the chain is too stretched and needs a new one.
Give it all a good clean, back pedal slowly to see how the chain looks along the teeth of chain ring/cassette/jockey wheels and use a chain stretch tool.
I can’t see from the vid: it couldn’t be the chain is wrongly routed between the jockey wheels? Last time I broke a chain I did that and managed a few km wondering why the chain was making an odd noise. It was well enough lubed to sort-of function. Doh…