Excessive chain slap noise with new 2X10 setup
I built up a Banshee Paradox with an XT M785 crank (28/40T), M780 GS rear derailleur (medium cage), M786 direct-mount front derailleur, and 11-36 cassette.
When I sized the chain, I wrapped around the largest chainring and largest cog, bypassing the rear derailleur, and added one link (two rivets).
I'm getting a lot of chain slap noise, even in the big ring, and it's driving me crazy. Every little bump you hit - clack-clack-clack-clack. At first I didn't have a chainstay protector, so I thought that was it and put on one of those neoprene lizard skins protectors. That didn't make any difference.
I picked up the bike and bounced it, and I can see that the noise is coming from the chain slapping the bottom of the front derailleur cage.
My chain shouldn't be too long based on my sizing method, and it doesn't seem like it's sagging or too long. I'm pretty certain there's nothing wrong with my FD installation, I used the clear/red tape thing that came on it to set the clearance, and it shifts just fine. Is this something you have to live with when running a 11-36 cassette? This is my first 2X10 setup, and also the first hardtail I've owned in at least 15 years. Is this a hardtail thing because there's no rear suspension smooth out the bumps?
Sometimes a long cage RD will help, and also using a Lizard Skin Chainstay guard will quiet things down a bit...
I recently installed one of these:
Search results for bionicon | Jenson USA Online Bike Shop
I am really liking it. Almost totally eliminated chain slap.
I am having the same problem with my XT 2X10. I am sure that I made the problem worse by changing the smaller chainring from 26T to 22T. The M785 FD has trouble handling that much of a gear difference (38-22=16T). I am also running a Bionicon and that has helped some. I looked for a smaller large chainring to reduce the FD teeth requirement but could not find one.
The shifting is fine and I only hear the chain slap when I am in the small/smallish gears. If it bothers me too much I may try a M780 FD to get the lower cage.
I have a SRAM XO derailleur in the back. It has a clutch in it that prevents chain slap, works great.
If the path ahead looks dangerous ------- it probably is!
Probably not the answer you would like to hear, but I think a Shadow Plus rear derailleur would fix the chain slap. I have one and my bike is silent.
I just ride in the big ring as much as possible...around here it's not difficult.
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