Chain length...

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Vetus Ossa
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Chain length...

Postby Vetus Ossa » 24 May 2016, 7:57pm

I have a bike set up with 10speed campag components, including a medium cage rear mech.
I am using a 26-36-48 chainset and 13-29 cassette.
The problem is as it is now I can’t use the big chainring and large sprocket together, which I probably will need to do at some point. I can if I add another link, but the chain droops when using the small cog and small chainring, and to be honest it’s not a huge problem as I never use that one.
The chain is connected with a power link.
I suppose I could use a long cage mech and that would sort it but I have read in other posts here that my current setup should work well enough.
I think if I joined the chain in the old way without the power link it would be perfect, but I would not be happy with that as I am not sure there would be enough pin each side of the chain plates to be reliable, and I like to take the chain off to clean it.
Do I put up with a slack chain in the lowest gear?

tatanab
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Re: Chain length...

Postby tatanab » 24 May 2016, 8:11pm

Vetus Ossa wrote:I think if I joined the chain in the old way without the power link it would be perfect,
Think about it and you will see that the power link adds no length - consider it as the 2 outer plates of the link you need anyway.
Do I put up with a slack chain in the lowest gear?
Yes because you may need the big-big because you have no time for a multiple front/back change, or you might try to use it accidentally forgetting which gear you are in. No reason to use little/little so it does not matter if the chain droops. If you have horizontal dropouts you might move the wheel back which might take up the droop. I have almost the same setup as you with a medium cage mech and get the little/little droop.

pwa
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Re: Chain length...

Postby pwa » 24 May 2016, 8:22pm

I can't see any problem with slackness in a chainring / sprocket combination that is never used. I would live with it. And your gear range would suit me nicely.

jb
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Re: Chain length...

Postby jb » 24 May 2016, 9:43pm

I've seen a bike get accidently put into big ring - big sprocket when the chain was not long enough, not pretty. The chain was so taught that the chain stay was on the edge of folding. especially when we had to lever it off the chain ring with a screwdriver. A slack chain on the smallest sprocket & chainring is unlikely to cause problems when accidently engaged.
Cheers
J Bro

Valbrona
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Re: Chain length...

Postby Valbrona » 25 May 2016, 2:30am

Your set up exceeds the capacity of the rear mech. It is up to you how you deal with it.

Can't understand why anyone would particularly want to use big/big on a triple because that same gear could be got elsewhere.
I should coco.

tim-b
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Re: Chain length...

Postby tim-b » 25 May 2016, 5:32am

Hi

I don't use big/big to avoid everything working at extremes; occasionally it happens through forgetting where I am on the cassette, so yes, I would have sufficient chain for this occurrence

Small/small is another extreme that you avoid, so maybe that's less of an issue??

Regards
tim-b
~~~~¯\(ツ)/¯~~~~

Brucey
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Re: Chain length...

Postby Brucey » 25 May 2016, 6:23am

Vetus Ossa wrote: .
The problem is as it is now I can’t use the big chainring and large sprocket together, which I probably will need to do at some point. I can if I add another link, but the chain droops when using the small cog and small chainring, and to be honest it’s not a huge problem as I never use that one.
.........Do I put up with a slack chain in the lowest gear?


yes, a slack chain in small-small is very much the lesser of two evils; IME if you can't use big-big safely then it is only matter of time until the transmission gets broken.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

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Vetus Ossa
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Re: Chain length...

Postby Vetus Ossa » 25 May 2016, 9:28am

Thanks all for your thoughts.
I should have perhaps added that this is a new (old frame, old parts) build and not fully sorted yet.
I do take the point regarding big ring/sprocket working properly as I do use that on one of my regular rides which involves a fast downhill stretch with a slight rise in the middle. I do this on the big ring and change up as the hill rises and usually end up on the big cog.
The odd thing is I have an almost identically set up bike, the one I will ride today, except it has a 46t chainring and that operates properly in all gears.
The chainstay is about ¼” longer on it but I can’t see that making that much difference.
Am I correct in thinking that adding a link to the chain on the problem bike is a no, no, I imagine it to be.

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Mick F
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Re: Chain length...

Postby Mick F » 25 May 2016, 11:16am

You must always have enough chain to get big/big.

Just imagine if you inadvertently select that gear and you don't have enough chain. All hell will break lose. :shock: :shock:

If your chain dangles somewhat in small/small, it doesn't matter. It just looks bad, but your bike will still work.
Mick F. Cornwall

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Vetus Ossa
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Re: Chain length...

Postby Vetus Ossa » 25 May 2016, 1:53pm

Mick F wrote:You must always have enough chain to get big/big.

Just imagine if you inadvertently select that gear and you don't have enough chain. All hell will break lose. :shock: :shock:

If your chain dangles somewhat in small/small, it doesn't matter. It just looks bad, but your bike will still work.



Yep, agreed. I used big/big today but have never actually used small/small so will lengthen my chain one link.

bainbridge
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Re: Chain length...

Postby bainbridge » 25 May 2016, 10:20pm

Another bonus of having a bit of slack on small/small is when you park the bike overnight (or longer) and put the gears in small/small you will be resting the rear derailleur jockey wheel housing spring.

I always do this on all my bikes, don't know if it's actually beneficial but it seems logical to me because it relieves tension on the shifter cables too.

andrewjoseph
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Re: Chain length...

Postby andrewjoseph » 26 May 2016, 2:39pm

unless you have a reverse action mech. :wink:
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