Possible cause for chain jump to smaller chain ring when cross chain
05-06-18, 06:42 PM
#26
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So many shifting issues, especially with the ft der, are rider controlled (or rider not well controlled
)I have seen a number of worn rings cause auto down shifting when work and when trying to use rather extreme chain angles. That the OP rides a bike with expensive parts is not the bike's fault. Once again the rider seeks blame somewhere else then it is found, or complains about their prior choices. Andy
05-06-18, 07:24 PM
#27
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This is the take away reply!
So many shifting issues, especially with the ft der, are rider controlled (or rider not well controlled)
I have seen a number of worn rings cause auto down shifting when work and when trying to use rather extreme chain angles. That the OP rides a bike with expensive parts is not the bike's fault. Once again the rider seeks blame somewhere else then it is found, or complains about their prior choices. Andy
So many shifting issues, especially with the ft der, are rider controlled (or rider not well controlled
)I have seen a number of worn rings cause auto down shifting when work and when trying to use rather extreme chain angles. That the OP rides a bike with expensive parts is not the bike's fault. Once again the rider seeks blame somewhere else then it is found, or complains about their prior choices. Andy
Oh come on,
you're blaming the rider because expensive parts shouldn't be expected to work as designed?
Cross chaining is not even a thing anymore.
05-06-18, 09:20 PM
#28
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I also "blamed" the rider for choosing expensive bikes with fancy parts that wear quicker then those of yesteryears then complain at how much stuff costs when they ride enough to wear things out. Skinnier chains and cog/ring teeth bearing surfaces with greater cross chaining angles equals faster wear. Rings that have brand unique bolt patterns have little or no other replacement options to help drive down replacement costs. The parts don't decide this. The manufacturer does and they see the way the buying public votes with their $. If the buying public stopped buying skinny chained bikes with limited gear range/steps and faster wearing parts the manufactures would have no choice but to change their business models or die. Of course this won't happen because, just like in politics, we are sold on the promise of every mile we ride will be our best ever.
The OP's description of the issue match with my many years of seeing worn out rings and large chain crossing angles. So his problem is quite likely from lots of use and the way the parts wear. That he chooses to also use the system at it's design limits means this wear is of even more consequence.
I'm good with being the mouth of common sense and reality. Sorry if it ruffles some people's feathers. Andy
05-06-18, 10:02 PM
#29
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No I'm not blaming the rider when parts don't work as intended. I do blame riders for their blaming their parts when they don't use them as well as they should, as well as others do and don't have the issues we see here so often. there's a reason why the industry wants to move away from ft ders. It's not that they can't be designed to work well, it's not that most pro wrenches can't figure out how to adjust them. It's because (IMO) so many riders don't take the time and effort to learn how to shift them in a way that has worked well for millions of others (and when the ders were far less detailed in their design). I teach shifting clinics and coach many new club riders in how to get the most out of their bikes and I've seen dozens of riders "see the light" in how to shift with less drama, how to read the road to know when shifting will be needed. All this is entirely within the riders control. how many posts do we read here where the bike shifts well on a stand but not on the road? Many. What's the difference? the rider's added stress on the system.
I also "blamed" the rider for choosing expensive bikes with fancy parts that wear quicker then those of yesteryears then complain at how much stuff costs when they ride enough to wear things out. Skinnier chains and cog/ring teeth bearing surfaces with greater cross chaining angles equals faster wear. Rings that have brand unique bolt patterns have little or no other replacement options to help drive down replacement costs. The parts don't decide this. The manufacturer does and they see the way the buying public votes with their $. If the buying public stopped buying skinny chained bikes with limited gear range/steps and faster wearing parts the manufactures would have no choice but to change their business models or die. Of course this won't happen because, just like in politics, we are sold on the promise of every mile we ride will be our best ever.
The OP's description of the issue match with my many years of seeing worn out rings and large chain crossing angles. So his problem is quite likely from lots of use and the way the parts wear. That he chooses to also use the system at it's design limits means this wear is of even more consequence.
I'm good with being the mouth of common sense and reality. Sorry if it ruffles some people's feathers. Andy
I also "blamed" the rider for choosing expensive bikes with fancy parts that wear quicker then those of yesteryears then complain at how much stuff costs when they ride enough to wear things out. Skinnier chains and cog/ring teeth bearing surfaces with greater cross chaining angles equals faster wear. Rings that have brand unique bolt patterns have little or no other replacement options to help drive down replacement costs. The parts don't decide this. The manufacturer does and they see the way the buying public votes with their $. If the buying public stopped buying skinny chained bikes with limited gear range/steps and faster wearing parts the manufactures would have no choice but to change their business models or die. Of course this won't happen because, just like in politics, we are sold on the promise of every mile we ride will be our best ever.
The OP's description of the issue match with my many years of seeing worn out rings and large chain crossing angles. So his problem is quite likely from lots of use and the way the parts wear. That he chooses to also use the system at it's design limits means this wear is of even more consequence.
I'm good with being the mouth of common sense and reality. Sorry if it ruffles some people's feathers. Andy
From what I hear, DI2 generally handles plenty of unkind shifting, & I certainly don't coddle my drivetrain (10 speed) but it works well.
Haven't even taken a shifting clinic....
07-20-21, 04:22 AM
#30
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The problem is that with the chain coming from an angle, the tips of the teeth aren't sliding in between the plates, but bumping against the edge of the inner plate. This is worst with the tooth immediately behind the shift gate. As the shift gate comes by, the chain moves over slightly because of the missing tooth, that makes the next tooth bump and derail it. So here are the options.
1- move the chainline inboard if it can be done by swapping spacers
2- use a chain with more inside bevel or bellmouth on the inner plates
3- file the outside of the tips of the teeth at a shallow angle. This moves the tips inboard making them more able to slip into the chain coming from an inside angle. Do this only by degrees until the problem resolves, and before getting carried away, understand that the tooth following the gap should be filed separately slightly a bit more because it's the one that needs the most help. In fact, it might make sense to file this one alone before filing all of them. Also be aware that if you carry this too far, it can cause problems when the chain feeds from the outside, so take it slow and check often.
1- move the chainline inboard if it can be done by swapping spacers
2- use a chain with more inside bevel or bellmouth on the inner plates
3- file the outside of the tips of the teeth at a shallow angle. This moves the tips inboard making them more able to slip into the chain coming from an inside angle. Do this only by degrees until the problem resolves, and before getting carried away, understand that the tooth following the gap should be filed separately slightly a bit more because it's the one that needs the most help. In fact, it might make sense to file this one alone before filing all of them. Also be aware that if you carry this too far, it can cause problems when the chain feeds from the outside, so take it slow and check often.
Resurrecting this old thread because I am having this issue. My sense is it started when I installed a new chain and chose YBN rather than sticking with SRAM, which I had used previously without this issue as far as I recall. My best course seems to be @FBinNY option 2, but before I go back to SRAM, are there other chains with more beveled plates that folks would recommend. I have generally run SRAM and KMC but chose YBN due to reports of durability and low friction. Also, besides changing chains, at the same time I installed a new RD (Shimano r8000 replacing r6800) and switched from SRAM 12-26 cassette to Shimano 11-30, so I am not certain my issue is chain related. Could any/all of those changes be an issue. The bike is a 2015 CAAD10, 11 speed Shimano shifters and derailleurs with SRAM Red 50-34 cranks.
