Please check my cha...
 

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[Closed] Please check my chain/Derailleur length calculations

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If I have a 22-32-44 chainset and I have a medium cage rear Derailleur with a max capacity of 34T and a minimum of 11T I am OK as long as I dont shift like a plank and go BIG-BIG arent I?

BIG front : SMALL rear = 44-11 = 33 = OK
BIG Front ; BIG Rear = 44-34 = 10 = SNAP?

Any others that will cause me trouble or just the BIG:BIG combo?


 
Posted : 19/10/2009 11:51 am
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calculations?

suck it and see...


 
Posted : 19/10/2009 11:57 am
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calculations?

suck it and see...

If I am going to be spending £140 ish on a new SRAM X.0 thats an expensive experiment that I am not willing to try!!!


 
Posted : 19/10/2009 12:00 pm
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dont thye usualy perscribe a range, so if its 45 (for example)

44-22 = 22
34-11 = 23

22+32 = 45 so it would be ok.

The capacity you've quoted is just the cassette size it can handle (i.e. wont go over 34t or cant get close enough to go lower than 11t).

Run the chain arround the big ring and sprocket, with the suspension at full compression (remove the shock) and add one full link (an inner and an outer) and voila, no chance of snapping the chain. If it flaps arround a bit too much at that remove a link at a time untill a comprimise is reached, but don't go big-big.


 
Posted : 19/10/2009 1:19 pm
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"If I am going to be spending £140 ish on a new SRAM X.0 thats an expensive experiment that I am not willing to try!!! "

I know what you mean but if its wrong it will probably pull the mech hanger off (forwards).

"Run the chain arround the big ring and sprocket, with the suspension at full compression (remove the shock) and add one full link (an inner and an outer) and voila, no chance of snapping the chain. If it flaps arround a bit too much at that remove a link at a time untill a comprimise is reached, but don't go big-big. "

Is the way to go.


 
Posted : 19/10/2009 1:33 pm
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I should have said its for a hard tail. I am not too worried about snapping the chain more the Derailleur so it should be ok if I just get the right chain length.

Going by the above figure of 45 then I dont think the medium is sufficient or is it ok as long as i dont go big:big?

The spec of the SRAm X.0 is as follows:

Chain capacity: 45T long / 37T Med / 30T Short
Max Sprocket: 34T
Min Sprocket 11T


 
Posted : 19/10/2009 1:46 pm
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wrap chain around big big but not through mech see were chain ends meet - add two links to that.. should be right..

you can always check by marking (bib-big + 2 links) the chain and then doing the same but with the mech and seeing what sort of of angle the rear mech is at before shortening it.. - particurly as sram chain are a pain if you cut them too short.


 
Posted : 19/10/2009 1:49 pm