Chain is too long, why make it shorter?
09-21-22, 04:30 PM
#26
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Sorry to be the messenger of bad news, but "auto-shifting" when backpedaling isn't fixable. It's inherent in the system.
Understand that the chain is precisely fed onto the sprockets by the derailleur, and in order for things to work nicely it has to be easy to move the chain from sprocket to sprocket. After all you wouldn't want to struggle shifting because of a willful chain that doesn't feel like moving over.
OTOH- there is no guide on the top of the cassette, so the chain is free to do whatever it pleases. The same "gates" (cut down or specially sculpted teeth) that improve shifting now make it easier for the chain to do it's thing when unguided. As a rule, the chain will shift towards better chain line, ie, towards the center of the cassette, or down to smaller sprockets because of gravity.
Your basic options are to either shift toward the middle of the cassette before having to walk the bike backward, or shift the RD to match where the chain has moved to so it spools smoothly and is ready for you to start riding.
It's not a big deal, and nothing to fret over, it's the nature of the beast, and for you to accept and adapt.
Understand that the chain is precisely fed onto the sprockets by the derailleur, and in order for things to work nicely it has to be easy to move the chain from sprocket to sprocket. After all you wouldn't want to struggle shifting because of a willful chain that doesn't feel like moving over.
OTOH- there is no guide on the top of the cassette, so the chain is free to do whatever it pleases. The same "gates" (cut down or specially sculpted teeth) that improve shifting now make it easier for the chain to do it's thing when unguided. As a rule, the chain will shift towards better chain line, ie, towards the center of the cassette, or down to smaller sprockets because of gravity.
Your basic options are to either shift toward the middle of the cassette before having to walk the bike backward, or shift the RD to match where the chain has moved to so it spools smoothly and is ready for you to start riding.
It's not a big deal, and nothing to fret over, it's the nature of the beast, and for you to accept and adapt.
Is it because of the different profile of the sprockets or because of a different derailleurs? Maybe both?
09-21-22, 04:45 PM
#27
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Imagine trying to watch the front door of a building while standing by the back door.
Since it's uncontrolled by the derailleur itself Auto shifting when back pedaling is purely a function of chain line and the specific profiles of both the sprocket teeth and chain links.
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09-22-22, 02:07 AM
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As I said earlier the RD cannot affect what's happening on the top of the cassette.
Imagine trying to watch the front door of a building while standing by the back door.
Since it's uncontrolled by the derailleur itself Auto shifting when back pedaling is purely a function of chain line and the specific profiles of both the sprocket teeth and chain links.
Imagine trying to watch the front door of a building while standing by the back door.
Since it's uncontrolled by the derailleur itself Auto shifting when back pedaling is purely a function of chain line and the specific profiles of both the sprocket teeth and chain links.
Found a few inconclusive discussions where BB or chainring spacers were discussed as a remedy for the problem. What's your opinion?
09-22-22, 01:22 PM
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....... my larger sprockets appear to have a few wider yet lower teeth. Downshifting is happening exactly where the chain meets them due to the chain angle on larger sprockets and the lack of the engagement on these teeth.
Found a few inconclusive discussions where BB or chainring spacers were discussed as a remedy for the problem. What's your opinion?
Found a few inconclusive discussions where BB or chainring spacers were discussed as a remedy for the problem. What's your opinion?
In any case, you probably don't have a problem here, except possibly between the ears. You're obsessing over nonsense instead of riding the bicycle, and NOT back pedaling in low gears when you should focus on the climb.
.....
Disregard those discussions about chain line because the so-callled improvement involves trade offs that may cause poorer performance or the creation of actual issues. I hesitate about saying more because it may lead you further down the rabbit hole, but suspecting that you can't let this go, here goes........
You can check your chainline with a straightedge about 18" or so long. Lay it (edgewise, not flatwise) on a secant across the chainring extending that plane back to the rear sprockets. it should end up 2 or so sprockets outside of the middle one. On center after allowing for the offset from the center of the chainrings) WARNING ---- there's plenty of fudge room, so if you're off by a bit, it's perfectly fine.
At this point , having nothing to add, I'll say good bye, and wish you good cycling
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An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
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