Bicycle Mechanics - chain goes "bump bump"

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signalnc
07-18-07, 08:37 PM
It started on the two smallest gogs on my rear cassette, now it does it on every cog. Bump Bump. I looked closely and the chain is riding up on the teeth (on 2 pins) then goes back in. I am assuming the chain is stretched? or can I adjust the wheel to go further into the drop out (it has set screws built in)?
Sounds like a bad link.
Find it and then flex the chain back and forth SIDEWAYS (the directions you would flex it if you were trying to break the chain).
That should do the trick.
AndrewP
07-18-07, 08:54 PM
Check for stiff link in the chain, then for bent derailer hanger.
signalnc
07-18-07, 08:57 PM
ok-thanks.. derailer looks ok--I'll check the chain. Thats probably it. I took it off , cleaned it then put it on and lubed it and thats when it started. I should have known I screwed something up. Thanks again
operator
07-18-07, 09:05 PM
ok-thanks.. derailer looks ok--I'll check the chain. Thats probably it. I took it off , cleaned it then put it on and lubed it and thats when it started. I should have known I screwed something up. Thanks again
If this is a 10 speed chain, you might not want to flex anything.
ok-thanks.. derailer looks ok--I'll check the chain. Thats probably it. I took it off , cleaned it then put it on and lubed it and thats when it started. I should have known I screwed something up. Thanks again
Yup. My guess is that the link is stiff where you broke the chain and then re-joined. Very typical problem.
Try my suggestion above and you should fix the problem fast and easy. The stiff link can be tricky to find sometimes, but you can do it. If you gently flex the whole chain (don't remove the chain from the bike for this), then you will get it for sure.
signalnc
07-19-07, 06:48 PM
ok- I found the link thats "sticky"---I can get the pin almost all the way in and it is fine, but when I push the pin in all the way the link almost freezes up. It's very hard to make it move. Is the pin bad?
Bob Dopolina
07-19-07, 07:13 PM
Yikes! Don't keep pushing the pin in and out. You will deform the holes in the plates and the pin will slip out under load, usually at a VERY inopportune moment!
The pin should be pushed in ONCE. What kind of chain is it? Did you use the appropriate replacement pin? What kind of tool are you using?
You need to stop what you are doing and double check some things before you go any further. You are at a point where you could potentially cause damage.
Proximo
07-19-07, 08:15 PM
Remove the link that is sticking and replace it with the appropriate Wipperman Connex Chain link, or equivalent. It'll make it easier in the future to pull the chain for maintenance.
No, no. Look, getting a sticky link when you break and then re-link is very common. Re-doing it or replacing the link is not the solution.
Just flex the damned chain like I told you and the problem will be solved.
Proximo
07-19-07, 10:32 PM
If he's been pushing the pin in and out, the link is weaker. He should replace it.
DannoXYZ
07-19-07, 10:56 PM
No, no. Look, getting a sticky link when you break and then re-link is very common. Re-doing it or replacing the link is not the solution.
Just flex the damned chain like I told you and the problem will be solved.yeah, this pretty much ALWAYS happen when you push a pin back in. What happens is the plates are pushed together tightly and then the pin is pushed in. This "pins" ;) the plates in the tight configuration.
To open up the spacing between the plates, just bend the chain SIDEWAYS (90-degrees to pin rotation) at the stiff link. Bending it one way, then the other will typically spread the plates apart enough free up the stiff link.
BikeManDan
07-20-07, 01:15 AM
No, no. Look, getting a sticky link when you break and then re-link is very common. Re-doing it or replacing the link is not the solution.
Just flex the damned chain like I told you and the problem will be solved.
Chain breakers usually have a special part on them specifically for fixing stuck links. It presses the pin and contorts the plates at an angle. 9 out of 10 times I have to use this when rejoining a chain. It fixes it 10 out of 10 times
yeah, this pretty much ALWAYS happen when you push a pin back in. What happens is the plates are pushed together tightly and then the pin is pushed in. This "pins" ;) the plates in the tight configuration.
To open up the spacing between the plates, just bend the chain SIDEWAYS (90-degrees to pin rotation) at the stiff link. Bending it one way, then the other will typically spread the plates apart enough free up the stiff link.
Yes, yes, Danno. That is what I am trying to say - bend the chain SIDEWAYS. Good description.
signalnc
07-20-07, 07:16 PM
i just went to perf. bike and bought a new one---I quit trying to bend it. thanks for the help gents
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