Poxy Chain

[Micheal]

Have a conundrum for all you mountain bikin nuts, to do with my chain. Before i start, apologies for the lack of technical terms used. I was out in Newry on the wkend and my chain got stuck a few times between the middle and big ring on the chain ring. Now by stuck, it seems to slip in under the big ring and lodge itself behind the middle ring. This is not the first time this has happened since i got the bike and is quite annoyin.


Any ideas on what is wrong or is it a case of sh@t happens?

[Morgan]

Hi Michael, I'm not really sure what you're describing. Does the chain fall down between the middle and big ring? If so I've never heard the like.


On the other hand, if the chain gets pulled up from below and wraps around the chainrings you're experiencing chainsuck. You can read about it in ridiculous detail here: http://www.fagan.co.za/Bikes/Csuck/

[Micheal]

I looked at that site and it turns out its not chain suck, but is dealt with on the site. The chain falls between the two rings and wont come out as it jams itself beneath the inner edge of the big ring.


The site says to fill the gap with epoxy which doesn't sound easy or the other option is to somehow get the rings closer together, is that possible?

[paddyobrien]

Hi Michael,


That definitely shouldn't be happening, and while i'm sure the epoxy thing would work, thats more a case of hiding the problem.


first off make sure that all the bolts holding on your chainrings are done up tightly, if not that might be the cause as the gap would be too big.


Have you or anyone ever taken the chainrings off the bike? (even a bike shop? they don;t always do things correctly) If so they may have been put back on wrong. Each ring has a little marker on it that should line up with the cranks. I've no idea how much of an effect this could have, but i can only assume shimano and others do this for a reason (probably to lineup the shifting ramps with the smaller teeth on the outer ring).


Other than that, how old is the chain and rings? Do they look obviously damaged?

[Micheal]

Bike was only bought last august and i have never taken it apart. Must look at the bolts etc to see if they are tight enough.


Thanks for the help lads

[NickJ74]

One way that might happen is if you're using a 9 speed chain on a 7 or 8 speed drivetrain? Ever replace the chain since August?

[Micheal]

No never had anything done with it. The chain rattles a lot when i go over any bumpy stuff. I was wondering if it is possible for the chain to be too long?

[Scrivo]

The chain could be too long (usually are when you buy a bike new as far as I know) but if the shifting is not sloppy, I would leave it. It wouldn't have anything to do with the chain getting stuck in between rings.


This is a very odd problem. One of the rings must either be bent or deformed. I would take the two of them off, switch them around and see if it still happens. It's probably just one part of the ring that's bent in a little.

[jonnieh]

if all else fails hit the damned thing with a hammer


trust me,i'm an engineer

[Micheal]

Took the chainring apart yesterday and it turned out the middle cog was bent in 1 spot. So being an engineer i decided that the only solution was brute force and ignorance. Seeing as i couldn't find a hammer i used a vice-grips for the panel beating. Looks a bit better than it did but as they say the proof is in the cycling.


Thanks for all the help lads


P.S. A vice-grips is not the best panel beating tool