Chain drops in Dahon Mu SL (2010)
Hi all, wondering if anyone can help with some suggestion on what i can do to fix this issue i have, before i bring the bike to the mechanic instead.
I have a DAhon Mu SL 2010, works fine, and runs well, got it new less than half a year ago. Probably done around 400 km on it as of now. Then last week, i was doing the normal clean cogs/lube chains, when, while trying out the shifting and pedaling by hand, the chain jumped out and got stuck in the gap between the chain guide and the chain guard. this happens when i shift to the smallest cog (i.e. from gear 8 to 9). I had to loosen the chain guide to be able to put the chain back on, and now i can almost replicate the issue 2 out of 3 times. On a friend's suggestion, i tried tightening the H screw on the RD to see if that resolves the issue, but the chain drops is still happening. I only done 2 turns - maybe it is insufficient? That said, i have ridden on the bike since then, with the chain guide away from the chain, and did not get any chain drops. Anyway, I am hoping for some suggestion on what to do, before i lug it to a LBS to get it fixed. Thanks in advance! |
The chain guard is meant to prevent chain drops. Sometimes they are not working properly be ause of being spaced to far away from the chainring. Is there a possibility of getting it closer?
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hi jur, are you referring to the chain guard, or the chain guide? the chain guard is fixed to the crankset (i hope i am getting the terminology right...) and doesnt look like it will be possible or easy to move. as for the chain guide, it can only move horizontally, as there is a metal ringlet blocking it from going higher, and right now, at the lowest gear/biggest cogs, the chain is slightly rubbing against the chain guide.
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The guard, which is fixed to the chainring. My Birdy's guard was also not close enough, so in the end I got my own solution in place and that worked. Unfortunately because of this being a custom part, it is not adjustable.
However, please ask ThorUSA for advice, he knows more than anybody about these bikes and may have a ready answer for you. |
Originally Posted by jur
(Post 16477103)
The guard, which is fixed to the chainring. My Birdy's guard was also not close enough, so in the end I got my own solution in place and that worked. Unfortunately because of this being a custom part, it is not adjustable.
However, please ask ThorUSA for advice, he knows more than anybody about these bikes and may have a ready answer for you. |
Hi tribe27. I had this same problem with my Tern X10 which is notorious for dropping chains. My LBS suggested a chain guard like the one you mentioned (by Tyrell) but the spacers were too thick to ensure it's effectiveness. I replaced the spacers with washers of my own and the problem was solved up to this point. I still can hear the chain attempting to drop off when there's a slight grinding noise for a couple of seconds before it normalizes. I'm not too about your Dahon but my Tern came with a very wide range cassette which is utterly useless. I had this cassette replaced with a 11-25T cassette and this has never been another chain drop even without the guard. Hope this helps, if you have not already solved it.
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Originally Posted by Shaunbee
(Post 16507883)
Hi tribe27. I had this same problem with my Tern X10 which is notorious for dropping chains. My LBS suggested a chain guard like the one you mentioned (by Tyrell) but the spacers were too thick to ensure it's effectiveness. I replaced the spacers with washers of my own and the problem was solved up to this point. I still can hear the chain attempting to drop off when there's a slight grinding noise for a couple of seconds before it normalizes. I'm not too about your Dahon but my Tern came with a very wide range cassette which is utterly useless. I had this cassette replaced with a 11-25T cassette and this has never been another chain drop even without the guard. Hope this helps, if you have not already solved it.
do you have pictures of the Tyrell chain guard, as well as the washers that you put in? As for cassette, i believe the one on my is SRAM PG980, 11-32T? I guess it will be a solution to keep in mind, to replace with a 11-25T. |
Don't be too sure that a different cassette will solve the problem. Chain drops are a result of the sideways snake movement that is imparted to the chain especially as it drops to a smaller cog. The sideways snake movement can cause the chain to climb the teeth of the chainwheel and drop off to the outside. A derailer will arrest the chain movement, or a chain guard IF it is close enough to the chain so that the snake bumps against the guard and dissipates before the chain climb on top of the teeth.
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Originally Posted by jur
(Post 16521676)
Don't be too sure that a different cassette will solve the problem. Chain drops are a result of the sideways snake movement that is imparted to the chain especially as it drops to a smaller cog. The sideways snake movement can cause the chain to climb the teeth of the chainwheel and drop off to the outside. A derailer will arrest the chain movement, or a chain guard IF it is close enough to the chain so that the snake bumps against the guard and dissipates before the chain climb on top of the teeth.
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I had this a lot on my 8 speed Mu. Tightening the RD screw did help for me. As does obsessive cleaning and lubing the chain and derailleur. It does still drop now and again. Usually at the worst time!
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The guard I fitted on my Birdy was aluminium; I had it as close as possible while not touching when in the extreme gears. From time to time I could hear a ping and think, "that is another dropped chain prevented", highly satisfying, that was.
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For MY customers who bought an x 10 or P9 Tern, I do have a new developed sharkteeth Chainring available, just in case they run into chain dropping problems.( Which isnt always the case ) BUT again I have to stress that, as long as I cannot buy any extra ones from Tern, I really cannot sell them to any other bike or customer. Tern came up with those and they are limited, obviously.
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I had the same problem on my Mu Sl. Especially when down shifting to smallest cog and pedaling at full speed over bumpy road. Could not fix it mechanically. But you can more or less eliminate it by pedaling a bit slower when shifting.
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Originally Posted by pibach
(Post 16526072)
I had the same problem on my Mu Sl. Especially when down shifting to smallest cog and pedaling at full speed over bumpy road. Could not fix it mechanically. But you can more or less eliminate it by pedaling a bit slower when shifting.
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Hi tribe027, Here's the link to the chainring guard by Tyrell.
http://www.flickr.com/photos/118571115@N07/12791782364/ |
There are several sizes on eBay from Driveline.
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Originally Posted by jur
(Post 16531361)
There are several sizes on eBay from Driveline.
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hey all, thanks a lot for the replies! apologies for the late delay in reply, as a lot has happened in the past month. shaunbee - thanks for the pic of the tyrell chainring guard. it looks similar to the chainguard that is on the mu sl though, maybe the dimensions are different which makes it work.
I agree with Shaunbee and jur's comments regarding the movement during a gear change - i can see the "jump" moving along the chain just before it reaches the chainwheel, and cause the chain to jump out of the chain guide. I did try holding off pedaling while shifting, but is still able to reproduce the problem, although it is less common. So for now, i just stop using the chain guide. No chain drops, and more importantly, if the chain does jump and drop, i can just put it back on without unscrewing the chain guide. thor - do you have a link on that sharkteeth chainring? i understand your comments about not being able to sell them, but if you can post a link, at least i know what to lookout for. jur, havm66z - what is this driveline you are referring to? |
[QUOTE=tribe027;16594857]I did try holding off pedaling while shifting, but is still able to reproduce the problem, although it is less common. So for now, i just stop using the chain guide. No chain drops, and more importantly, if the chain does jump and drop, i can just put it back on without unscrewing the chain guide.
QUOTE] hi tribe027, consider carrying a rag in your saddle bag. At the time I was experiencing chain drops, reinstating the chain inevitably messes my fingers/hands. Having white Ergon grips on my X10 doesn't help. Once home, I have to carry my white X10 into the house (most Singaporeans live in apartments). Yes, its messy. So the rag really comes in handy after you got your chain back in place. Anyway, I have not gotten to use that piece of rag since I made the changes that I felt did the trick. Still, there could be a time when the chain decides to drop off again and I'll have clean hands after that. |
Rag? Leaves,newspaper,sticks;I've always been able to find something within reach to deal with a dropped chain without getting grease on my fingers.
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Originally Posted by dynaryder
(Post 16599410)
Rag? Leaves,newspaper,sticks;I've always been able to find something within reach to deal with a dropped chain without getting grease on my fingers.
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Originally Posted by Call Me Al
(Post 16603507)
Silicone gloves. If you carry them the god of folding bikes will notice you are prepared. That way he might pester someone else instead!
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Originally Posted by Shaunbee
(Post 16507883)
Hi tribe27. I had this same problem with my Tern X10 which is notorious for dropping chains. My LBS suggested a chain guard like the one you mentioned (by Tyrell) but the spacers were too thick to ensure it's effectiveness. I replaced the spacers with washers of my own and the problem was solved up to this point. I still can hear the chain attempting to drop off when there's a slight grinding noise for a couple of seconds before it normalizes. I'm not too about your Dahon but my Tern came with a very wide range cassette which is utterly useless. I had this cassette replaced with a 11-25T cassette and this has never been another chain drop even without the guard. Hope this helps, if you have not already solved it.
can i seek ur advice on the chaindrop issue of verge x10? just gotten a new x10 bike..together with the tyrel protector as advised. thank you! |
Hi Sherilyn. Since you already got the chainring guard, the next thing to do is to adjust the chain keeper, that black plastic thing on the seat tube. The chainring guard is to prevent the chain from dropping onto the outside while the chain keeper is to prevents drops onto the inside. If on the highest gear and you hear a slight grinding noise, it's probably the chain rubbing against your chainring guard. Have your LBS install thicker washers between the chainring and chainring guard. If on the lowest gear and you a dull rubbing noise, the chain is rubbing against the chain keeper. A screwdriver and a little adjustment is all you need to do. Give it a try!
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Originally Posted by Call Me Al
(Post 16603507)
Silicone gloves. If you carry them the god of folding bikes will notice you are prepared. That way he might pester someone else instead!
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