Do these RD positions look normal (chain length inquiry)
#1
bill nyecycles
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Do these RD positions look normal (chain length inquiry)
No matter how many times I watch a video I’m always worried I didn’t size them chain properly. This is a brand new build so I’ve got no existing chain to compare it too.
I did the whole big ring big ring match up and add 2 links.
I haven’t dialed in the RD yet so the chain only goes up to the second to last cog, but I feel like maybe it’s straining too much already? Is that an indicator of chain being too short?
Any I’m not sure if pictures help because every setup is different, but I took some pics of big-small, small-small, and big-big. Let me know if they look correct-ish? Or if I need to go buy another chain and try again.
I did the whole big ring big ring match up and add 2 links.
I haven’t dialed in the RD yet so the chain only goes up to the second to last cog, but I feel like maybe it’s straining too much already? Is that an indicator of chain being too short?
Any I’m not sure if pictures help because every setup is different, but I took some pics of big-small, small-small, and big-big. Let me know if they look correct-ish? Or if I need to go buy another chain and try again.
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That's fine. You could go one link set longer if you wanted to, but what you'd done is good.
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In pic 3 you don't seem to be in the biggest rear cog (physically biggest, not biggest by ratio).
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You are fine just the way it is. Small-small isn't completely slack and big-big isn't stretched too tight.
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Those teeth appear to be sticking right through the rollers on the chain. So I'll think that cog is behind the chain.
Last edited by Iride01; 06-04-22 at 10:16 AM.
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I was looking at the top & missed that. Good eye!
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What I would try is reducing the chain wrap by about 1/4" & increasing the initial forward sweep ratio a 1/4 turn at the rear der.
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Looks pretty good to me although you should try the big/big combo to make sure the derailleur cage isn't near horizontal in that gear but lengthening the chain may cause interference on the small/small. Solution is to try not to use the big/big or small/small and all other combos will be fine.
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#13
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The danger choice is the biggest to biggest combo. The smallest to smallest might result in some odd shifting or even jump the chain. But it'll be embarrassing and recoverable rather than disastrous. The risk is a solid stretch and bind where the chain goes "hard tight" and bad things going "BOOM!".
Once you adjust things so it does fit big to big try it again. Ensure that as the chain climbs over the crests of the teeth at both front and then at the rear that the chain does not actually go solidly tight. If it does you'll need to add another link pair.
You'll know it's tight when you feel the slowly turning pedal cranks go " hard tight" over a very few degrees of pedal travel. So do turn the cranks fairly slow like one rev over about 2 seconds or so. So fast enough that it'll shift cleanly. But slowly enough that if the chain does get firmly and "hard pebble" tight you can just stop the pedals before anything sees excessive force.
You're looking to avoid the sort of feel you get when a grocery cart wheel has to bump over a pebble. It will get "springy" tight due to the extension of the derailleur. That'll be felt as a gradual rise in the firmness in the hand pressure. But you want to avoid a hard bump sort of feel in the pedal crank as you turn it smoothly by hand. If you feel it suddenly get very firm over just a few degrees of rotation that's time to stop.
That's a lot of description of something which can be hard to put clearly into words. I hope it helps.
Once you adjust things so it does fit big to big try it again. Ensure that as the chain climbs over the crests of the teeth at both front and then at the rear that the chain does not actually go solidly tight. If it does you'll need to add another link pair.
You'll know it's tight when you feel the slowly turning pedal cranks go " hard tight" over a very few degrees of pedal travel. So do turn the cranks fairly slow like one rev over about 2 seconds or so. So fast enough that it'll shift cleanly. But slowly enough that if the chain does get firmly and "hard pebble" tight you can just stop the pedals before anything sees excessive force.
You're looking to avoid the sort of feel you get when a grocery cart wheel has to bump over a pebble. It will get "springy" tight due to the extension of the derailleur. That'll be felt as a gradual rise in the firmness in the hand pressure. But you want to avoid a hard bump sort of feel in the pedal crank as you turn it smoothly by hand. If you feel it suddenly get very firm over just a few degrees of rotation that's time to stop.
That's a lot of description of something which can be hard to put clearly into words. I hope it helps.
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Oh well, who reads anyway today? Especially when we got good pics and a well written title! My bad, might have done better in high school if I'd just read the text books..
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bill nyecycles
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The danger choice is the biggest to biggest combo. The smallest to smallest might result in some odd shifting or even jump the chain. But it'll be embarrassing and recoverable rather than disastrous. The risk is a solid stretch and bind where the chain goes "hard tight" and bad things going "BOOM!".
Once you adjust things so it does fit big to big try it again. Ensure that as the chain climbs over the crests of the teeth at both front and then at the rear that the chain does not actually go solidly tight. If it does you'll need to add another link pair.
You'll know it's tight when you feel the slowly turning pedal cranks go " hard tight" over a very few degrees of pedal travel. So do turn the cranks fairly slow like one rev over about 2 seconds or so. So fast enough that it'll shift cleanly. But slowly enough that if the chain does get firmly and "hard pebble" tight you can just stop the pedals before anything sees excessive force.
You're looking to avoid the sort of feel you get when a grocery cart wheel has to bump over a pebble. It will get "springy" tight due to the extension of the derailleur. That'll be felt as a gradual rise in the firmness in the hand pressure. But you want to avoid a hard bump sort of feel in the pedal crank as you turn it smoothly by hand. If you feel it suddenly get very firm over just a few degrees of rotation that's time to stop.
That's a lot of description of something which can be hard to put clearly into words. I hope it helps.
Once you adjust things so it does fit big to big try it again. Ensure that as the chain climbs over the crests of the teeth at both front and then at the rear that the chain does not actually go solidly tight. If it does you'll need to add another link pair.
You'll know it's tight when you feel the slowly turning pedal cranks go " hard tight" over a very few degrees of pedal travel. So do turn the cranks fairly slow like one rev over about 2 seconds or so. So fast enough that it'll shift cleanly. But slowly enough that if the chain does get firmly and "hard pebble" tight you can just stop the pedals before anything sees excessive force.
You're looking to avoid the sort of feel you get when a grocery cart wheel has to bump over a pebble. It will get "springy" tight due to the extension of the derailleur. That'll be felt as a gradual rise in the firmness in the hand pressure. But you want to avoid a hard bump sort of feel in the pedal crank as you turn it smoothly by hand. If you feel it suddenly get very firm over just a few degrees of rotation that's time to stop.
That's a lot of description of something which can be hard to put clearly into words. I hope it helps.
and yeah now that I have this many gear options I probably won’t put myself into big-big very often - I’m used to my downtube friction shift 2x6 that does big - big just fine but is a normal gear because those old cassettes are much smaller tooth count.
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#18
bill nyecycles
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ok got the RD dialed in - here’s a pic of it in big-big. I don’t foresee me using this gear much. The chain isn’t super tight. I can still push it with my finger between the jockey and the crank and it gives probably 3/4” or more.
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My favorite story was the one about the trick test where the INSTRUCTIONS stated to simply fill in the student's name and do either no questions or only the last then wait quiety. Apparently the lion's share madly read and answered all the questions. Just one or two read the instructions and did as instructed....... I try to pretend I'm a little like a lawyer and read things more carefully ever since. Especially since even when they didn't intend to be confusing some teachers wrote questions that made one stop and say "Wha.... ? ! ? ! ? ! ?"
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#20
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That looks great. You've easily got enough to deal with the chain passing over the teeth. But it's not so loose that you could remove a whole link pair without causing an issue either. And as you showed in the opening post pics the small-small does not cause the idler cogs to rub at all. So... NAILED IT!
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bill nyecycles
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Wouldn't we all have... wouldn't we all.....
My favorite story was the one about the trick test where the INSTRUCTIONS stated to simply fill in the student's name and do either no questions or only the last then wait quiety. Apparently the lion's share madly read and answered all the questions. Just one or two read the instructions and did as instructed....... I try to pretend I'm a little like a lawyer and read things more carefully ever since. Especially since even when they didn't intend to be confusing some teachers wrote questions that made one stop and say "Wha.... ? ! ? ! ? ! ?"
My favorite story was the one about the trick test where the INSTRUCTIONS stated to simply fill in the student's name and do either no questions or only the last then wait quiety. Apparently the lion's share madly read and answered all the questions. Just one or two read the instructions and did as instructed....... I try to pretend I'm a little like a lawyer and read things more carefully ever since. Especially since even when they didn't intend to be confusing some teachers wrote questions that made one stop and say "Wha.... ? ! ? ! ? ! ?"
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the sci guy You are making very good progress on your CAAD4. The photo in post #18 above looks fine. How is the same chain in small / small?
Not that you should ever ride in that combination. Shimano dealer manual for the FD says to expect chain rub when on the small chain ring and the four smallest cogs. DM-RAFD001-05-ENG.pdf (shimano.com) at page 4.
The huge difference in RD position between big/big and small/small (in post #1) is to be expected given that you are using a GS derailleur and the biggest possible cassette (11-34) for that RD.
Not that you should ever ride in that combination. Shimano dealer manual for the FD says to expect chain rub when on the small chain ring and the four smallest cogs. DM-RAFD001-05-ENG.pdf (shimano.com) at page 4.
The huge difference in RD position between big/big and small/small (in post #1) is to be expected given that you are using a GS derailleur and the biggest possible cassette (11-34) for that RD.
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No matter how many times I watch a video I’m always worried I didn’t size them chain properly. This is a brand new build so I’ve got no existing chain to compare it too.
I did the whole big ring big ring match up and add 2 links.
I haven’t dialed in the RD yet so the chain only goes up to the second to last cog, but I feel like maybe it’s straining too much already? Is that an indicator of chain being too short?
Any I’m not sure if pictures help because every setup is different, but I took some pics of big-small, small-small, and big-big. Let me know if they look correct-ish? Or if I need to go buy another chain and try again.
I did the whole big ring big ring match up and add 2 links.
I haven’t dialed in the RD yet so the chain only goes up to the second to last cog, but I feel like maybe it’s straining too much already? Is that an indicator of chain being too short?
Any I’m not sure if pictures help because every setup is different, but I took some pics of big-small, small-small, and big-big. Let me know if they look correct-ish? Or if I need to go buy another chain and try again.
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#24
bill nyecycles
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Afternoon update:
dialed in the RD as mentioned above, finished off wrapping the bars and got my saddle on, set my seat height and took it for a quick spin around the neighborhood…
And everything shifted very well. A few clicks or minor rub on the FD but overall I think I got it.
Thanks for the input, yall. Definitely relieved some stress I was having.
dialed in the RD as mentioned above, finished off wrapping the bars and got my saddle on, set my seat height and took it for a quick spin around the neighborhood…
And everything shifted very well. A few clicks or minor rub on the FD but overall I think I got it.
Thanks for the input, yall. Definitely relieved some stress I was having.