Optimal Chainlength - It's A New Day

[kdawg]

Found the links to my chain and added them (I hate those Shimano joining pins!). Just to check - the black line is where I can get the chain to if I pull it tight, so 1 is the the first place I could join it so I’m going to add 2 links and use point 3? (Although I left the quick link there to remind me that I’ll actually break the chain at 2 and that will add a link).



Thanks.

[kdawg]

I have a chain length question too
I'm thinking of building a bike up with a 1x 10*, 40/11-32 and am a little confused about how the single chainring affects how you size the chain. So far (using 2x) I've used the formula method to satisfactory effect, but does it work with 1x? Should I size the chain using the biggest sprocket (shortest** possible chain) or the smallest (longest possible chain)? Using the big sprocket, I'm afraid the chain will be too slack in the smaller sprockets and I'll get excessive chain-slap, and using the small sprocket, I'm afraid I'll make the chain too short to clear the 32.

*with a short cage RD, should work given that there's less slack to take up with only one chainring.
**within reason of course.

Found the dealer manual that says to add 2 links.

[Clean39T]

Progress is great, eh?


****

EDITED to not sound quite so grumpy...

[Calnago]

Found the links to my chain and added them (I hate those Shimano joining pins!). Just to check - the black line is where I can get the chain to if I pull it tight, so 1 is the the first place I could join it so I’m going to add 2 links and use point 3? (Although I left the quick link there to remind me that I’ll actually break the chain at 2 and that will add a link).



Thanks.

@Kdawg: I think you’ve got it pretty well sussed out, but I actually do like using the Shimano quick link. Especially if you have their own pliers for both installing and removal.

[Calnago]

I have a chain length question too
I'm thinking of building a bike up with a 1x 10*, 40/11-32 and am a little confused about how the single chainring affects how you size the chain. So far (using 2x) I've used the formula method to satisfactory effect, but does it work with 1x? Should I size the chain using the biggest sprocket (shortest** possible chain) or the smallest (longest possible chain)? Using the big sprocket, I'm afraid the chain will be too slack in the smaller sprockets and I'll get excessive chain-slap, and using the small sprocket, I'm afraid I'll make the chain too short to clear the 32.

*with a short cage RD, should work given that there's less slack to take up with only one chainring.
**within reason of course.

Found the dealer manual that says to add 2 links.

@themidge: I really don’t want to get into discussing bastardized or untested solutions to things, but I would say that the in your case the critical factor (assuming enough chainlength and capacity) might simply be the geometry of your short cage derailleur and the hanger specs. You might find that the derailleur simply doesn’t move along a “parallelogram” that will accommodate such a wide range cassette while providing adequate shifting across the range.

[Calnago]

Progress is great, eh?
EDITED to not sound quite so grumpy...

Ha! I did see your initial post a few days ago before your edit but just now responding. I hear ya... sometimes progress is actually that, progress. And other times it’s well, maybe something a little different for lack of a better description. But really, properly set up, the new derailleurs really work well.

[themidge]

...critical factor (assuming enough chainlength and capacity) might simply be the geometry of your short cage derailleur and the hanger specs. You might find that the derailleur simply doesn’t move along a “parallelogram” that will accommodate such a wide range cassette while providing adequate shifting across the range.

Yeah I was thinking it'd be that, I guess I'll just have to try it. As far as I can tell, the upper geometry of short, mid, and long cage RDs are all the same (the only difference being the cage length) so in theory a short cage RD should clear a 32 when it can manage the chain length.

[kdawg]

Found the links to my chain and added them (I hate those Shimano joining pins!). Just to check - the black line is where I can get the chain to if I pull it tight, so 1 is the the first place I could join it so I’m going to add 2 links and use point 3? (Although I left the quick link there to remind me that I’ll actually break the chain at 2 and that will add a link).



Thanks.

@Kdawg: I think you’ve got it pretty well sussed out, but I actually do like using the Shimano quick link. Especially if you have their own pliers for both installing and removal.

Thanks - and I love the quick link, it’s the snap off pin I used to put the other links back on that I don’t like. Can’t remember ever having one fail but they just never felt like a good solution.

[Calnago]

@kdawg: ok, I must have misread you as I thought it was the quick link you didn’t like.

[kdawg]

Put back together and this looks a lot nicer. I’m not sure that I knew that the Ultegra chain I have is directional so that might help too - although shifting was pretty crisp before I’ll see what it’s like now.

[mattr]

As far as I can tell, the upper geometry of short, mid, and long cage RDs are all the same (the only difference being the cage length) so in theory a short cage RD should clear a 32 when it can manage the chain length.

Depends on the model/brand/year. There are a few (not many) where the short cage mech has a slightly diffierent body and/or location of the top jockey.

Can catch you out sometimes
Though i doubt there is anything current that'll catch you out.

Have you checked the manufacturers spec for that exact model of mech? (Capacity and largest/smallest sprocket?)

[nycebo]

Thanks for the super fast reply. I’ll see if I can find the links I removed. Unless there’s a problem with that and I should replace it?

I agree that it's a bit tight, but I think that you can ride it until it's worn without real detriment. Maybe just try and stay out of big/big crosschain until the next chain.

[BdaGhisallo]

I have just come back home from a two week plus vacation and it was my first chance to apply the chain length info presented in this thread. My 9150 setup was noticeably louder than the 9070 setup on my other bike and I was sure that I must not have had the chain length on the 9150 bike correct. I pulled it out of the RD and did the test and it was bang on! I did loosen the B screw a bit and got the 9150 RD more tucked under and forward of the cassette so that will help shifting a good bit.

I guess 9150 is just louder than 9070 - full stop. Granted my 9150 drivetrain doesn't have too many miles on it yet so I am curious if the noise abates some once I get it run in a bit.

[Bigger Gear]

I have just come back home from a two week plus vacation and it was my first chance to apply the chain length info presented in this thread. My 9150 setup was noticeably louder than the 9070 setup on my other bike and I was sure that I must not have had the chain length on the 9150 bike correct. I pulled it out of the RD and did the test and it was bang on! I did loosen the B screw a bit and got the 9150 RD more tucked under and forward of the cassette so that will help shifting a good bit.

I guess 9150 is just louder than 9070 - full stop. Granted my 9150 drivetrain doesn't have too many miles on it yet so I am curious if the noise abates some once I get it run in a bit.

This is my conclusion as well, after playing around with chain length, B-tension, different cassettes, and voodoo chants. I cannot get 9100 or 8000 to run as quietly as 9000 or 9070. I have no experience (yet) with 9150 but I can't see why it would magically run quieter than a perfectly new and adjusted 9100 group.

[BdaGhisallo]

I have just come back home from a two week plus vacation and it was my first chance to apply the chain length info presented in this thread. My 9150 setup was noticeably louder than the 9070 setup on my other bike and I was sure that I must not have had the chain length on the 9150 bike correct. I pulled it out of the RD and did the test and it was bang on! I did loosen the B screw a bit and got the 9150 RD more tucked under and forward of the cassette so that will help shifting a good bit.

I guess 9150 is just louder than 9070 - full stop. Granted my 9150 drivetrain doesn't have too many miles on it yet so I am curious if the noise abates some once I get it run in a bit.

This is my conclusion as well, after playing around with chain length, B-tension, different cassettes, and voodoo chants. I cannot get 9100 or 8000 to run as quietly as 9000 or 9070. I have no experience (yet) with 9150 but I can't see why it would magically run quieter than a perfectly new and adjusted 9100 group.

Thinking about it further and looking at my two bikes side by side this morning, the increased noise may simply be due to the greater wrap of the 9100 gen RDs. I counted 15 chain links engaged with the cassette when it's in the 39x28 combo. On the 9150 bike, 19 chain links are engaged in that same combo.

More contact = more friction = more noise? Could it be that simple?