Chain to long?

Discuss light weight issues concerning mountain bikes & parts.

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HaakonJohansen
Posts: 284
Joined: Mon Sep 01, 2014 4:58 pm

by HaakonJohansen

My drivetrain is quite noisy, and I'm starting to think that my chain is too slack. The noise comes from the side of the chain repositioning itself, "clapping" against the larger cog on its side (kind of difficult to explain). A friend of mine installed it (he's a bike mechanic), but he did it for free in he's work time, so he hadn't got too much time, and said the chain should work alright. So currently I'm using all the links (don't know how many, but I guess between 112 and 116). It's an 1x11 speed drivetrain, SRAM 10-42 cassette, XTR M9000 derailleur (medium cage as it was on sale), 36T RF up front, and 428mm chain stays.

I have to confess that the derailleur cable has got a little bend from earlier mounting, as I had to use a bit longer housing. I guess this might make some problems as well, but I wanna hear what you guys think about the chain as well. The two pictures below is to show the derailleurs position when in the lowest and highest gear.

Image
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szymonef
Posts: 58
Joined: Tue Apr 23, 2013 9:05 pm

by szymonef

Are you sure that's a medium cage? I would say that's SGS - long cage derailleur. Ad chain: it could be 2 links shorter, however it's very unlikely that drivetrain noise is now caused by its length - try to look somewhere else. Is it perfectly adjusted? Alloy pulleys are for sure louder than standard (plastic) ones in RD-M9000

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mattr
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by mattr

If the chain is catching on the side of the cog next to it, i'd be looking at bent hanger and cable adjustment before chain length.

Also, is the top jockey a floater or fixed? Could be an issue. One reason i stick with shimano pulleys. They actually work better than 99% of the alternatives.

HaakonJohansen
Posts: 284
Joined: Mon Sep 01, 2014 4:58 pm

by HaakonJohansen

mattr wrote:If the chain is catching on the side of the cog next to it, i'd be looking at bent hanger and cable adjustment before chain length.

Also, is the top jockey a floater or fixed? Could be an issue. One reason i stick with shimano pulleys. They actually work better than 99% of the alternatives.

Thanks for the replies. What does floater and fixed mean? Does it have anything to do with the length of the teeth on the pulley wheel? The teeth are short on both the pulleys, as opposed to the long teeth on the top pulley of the Shimano. It doesn't always make this noise, so I guess the bent cable can have a bad influence on the system (it makes the derailleur alignment change slightly from time to time). I know the pulleys themselves makes more noise than the original Shimanos, but I actually kind of like that noise, so that's not whats bothering me. Also, the chainline with the original RF ring doesn't help either. I'm thinking of getting a Garbaruk ring.

New derailleur cable will be my first cause of action I guess. I'm thinking about getting the Mini I-Links.

mattr
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by mattr

HaakonJohansen wrote:What does floater and fixed mean?
Shimano top jockey wheels have about 2mm of side to side float to allow for slight misalignment of mech/hanger/cassette. Most (but not all) aftermarket jockey wheels are fixed, so they are very very intolerant to any slight misalignment. They then make lots of noise.
HaakonJohansen wrote:so I guess the bent cable can have a bad influence on the system (it makes the derailleur alignment change slightly from time to time).
If the cable is making the mech position change, it's almost certainly too short. This will have the knock on effect of moving the mech from side to side as well.

Get some i-links and try very slightly longer (might only need an extra 1cm)

And i've just had a look, as i could vaguely rmember shimano deleting the floating top jockey some time ago in MTB mechs........... and yours didn't have one....... So you can forget about that. Check gear hanger and outer cable.

HaakonJohansen
Posts: 284
Joined: Mon Sep 01, 2014 4:58 pm

by HaakonJohansen

mattr wrote:
HaakonJohansen wrote:What does floater and fixed mean?
Shimano top jockey wheels have about 2mm of side to side float to allow for slight misalignment of mech/hanger/cassette. Most (but not all) aftermarket jockey wheels are fixed, so they are very very intolerant to any slight misalignment. They then make lots of noise.
HaakonJohansen wrote:so I guess the bent cable can have a bad influence on the system (it makes the derailleur alignment change slightly from time to time).
If the cable is making the mech position change, it's almost certainly too short. This will have the knock on effect of moving the mech from side to side as well.

Get some i-links and try very slightly longer (might only need an extra 1cm)

And i've just had a look, as i could vaguely rmember shimano deleting the floating top jockey some time ago in MTB mechs........... and yours didn't have one....... So you can forget about that. Check gear hanger and outer cable.

Thanks for some very informative info! Quite a stupid guess by me on the fixed pulleys (or jockeys? I'm a bit confused about that);P You're right; the Shimano pulley doesn't have any sideways play, but my aftermarket one has a bit of it. I don't think this is the problem though, because the noise did sometimes occur with the original pulleys as well.

Edit: I measured the cage length and it is indeed the medium version (84mm).

As you can see in the pic, the cable is bent from previous clamping position. This might cause the cable to have some play in it I guess.
Image

BikeAnon
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by BikeAnon

I have nothing useful to add that can help you. I just stopped by to say a giant THANK YOU for providing excellent pictures and details in your posts.

HaakonJohansen
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by HaakonJohansen

BikeAnon wrote:I have nothing useful to add that can help you. I just stopped by to say a giant THANK YOU for providing excellent pictures and details in your posts.

I'm really glad to hear that that someone appreciates my posts:) Thanks for the positive feedback!

CGT
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Location: Stockholm, Sweden

by CGT

I appreciate your posts too! And I don't think the kink in the wire should affect your shifting at all.

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Getter
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by Getter

If you are using third party jockey wheels...I suggest that you put the factory upper pulley wheel back and see if that helps. I have an X0 derailleur and when I tried a third party jockey...it made shifting worse. I just ended up using the lower one and kept the factory upper one.

The short housing shouldn't affect the shifting in the way you're describing, but going with a longer housing won't hurt. The housing should enter the derailleur stop in a straight fashion. Yours looks to have a slight kink when entering the derailleur.

afalts
Posts: 157
Joined: Thu Mar 08, 2012 3:20 pm

by afalts

I had a very similar set up to you last year. I had one wheelset with an XO1 cassette, and one with an XTR 11-40 cassette. The XTR cassette was WAY quieter. I never had a single shift issue, or any issue really, with either cassette, but the SRAM one was noisy.

Chain length looks ok. In my experience a shorter chain is usually noisier actually.
I wouldn't really recommend Mini I-links. Stick with Shimano SP-41 housing and their Polymer coated cables. They really are the best performing combo.

Finally, I used that KMC chain, a SRAM one, and an XTR one. The XTR one was the quietest, KMC made the most 'chatter'. XTR everything was always the quietest and smoothest setup. I really enjoyed the XO1 cassette range though for longer days with bigger hills.

HaakonJohansen
Posts: 284
Joined: Mon Sep 01, 2014 4:58 pm

by HaakonJohansen

Thanks again for the feedbacks. I dont think the stort housing is the problem, but the bent cable might be. As well as the chainline. Also, like i said, the sound did sometimes occur with the original pulleys as well, and shifting is just as good with the new ones. I really think the main issue is the chainline though. I'm using a bb spacer on the drive side as well, which makes this problem worse, of course. But I do need one bb spacer, and if I'm putting it on the other side the crank position will be way off. Gearing is fine, like I said, but the sound isn't very pleasing. I do think it's worse when backpedaling though. Should I maybe opt for the Wolftooth over the Garbaruk maybe? As it's got a mm narrower chainline, I mean.

Edit: I just found out that the 36T version of the Wolftooth ring has the same chainline as the original RF, so I guess I'll end up buying the Garbaruk. Maybe I'll even try out an oval ring. If I do, I'll consider Absolute Black as well. Anyone who's compared these two brands?

stormyClouds
Posts: 17
Joined: Thu Jan 17, 2008 4:37 pm
Location: Michigan

by stormyClouds

I would take a quick look at the chain length - if it is too long, that is the easiest solution.
Remove the chain and wrap it around the biggest cog and biggest chainring. Where the 2 ends meet, you want to have an additional 2 links.
If you have more than that, take out the excess links.

TheRookie
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by TheRookie

Epic resurrect!
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stormyClouds
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Joined: Thu Jan 17, 2008 4:37 pm
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by stormyClouds

Haha, didn't realize this was that old.
Hope that he got his chain length sorted in the last 6 months, lol.

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