Chain length?
03-31-08, 05:57 PM
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Chain length?
What does it mean when your lower jockey pulley on your rear derailleur is fairly far forward toward the crank when in the biggest cog? And perpendicular to the ground in the smallest cog? Bike is a 1x7, 42 front 12-28 or so rear. Is my chain too long or too short?
03-31-08, 06:17 PM
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If every gear combo is accessible and the rear derailleur does not fold into itself in the smallest chainring/smallest cog, then the chain length is fine. You have a lot of leeway in a 1xwhatever setup. Your setup sounds fine.
For the absolute shortest chain you can run, follow the steps here: https://sheldonbrown.com/derailer-adjustment.html#chain
For the absolute shortest chain you can run, follow the steps here: https://sheldonbrown.com/derailer-adjustment.html#chain
03-31-08, 07:58 PM
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It may mean that your RD is doing exactly what it is designed to do, that is tension the chain and take up slack as you shift from low-high (shortest chain needed) to high-low (longest chain needed). And if as said above "If every gear combo is accessible and the rear derailleur does not fold into itself in the smallest chainring/smallest cog, then the chain length is fine." and IT IS DOING AS IT SHOULD! That also presumes it is adjusted properly and shifts between gears smoothly and precisely.
04-01-08, 02:10 PM
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shimano say: put chain on largest cog & largest chainring, pull chain tight, then add two links. remove the unwanted part of the chain.
for bigger cogs you need a medium or long cage rear mech
for bigger cogs you need a medium or long cage rear mech
04-01-08, 07:00 PM
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That's not quite complete. Generally, the largest cog size determines the style of derailleur (27T or smaller=Road; 28T or larger=MTB) and the number of chainrings determines the length of the cage (Single/Double=Road SS/short or MTB GS/short/medium; Triple=Road GS/medium/long or MTB SGS/long).
See post 114 for the chart: https://bikeforums.net/showthread.php?t=316561&page=5
See post 114 for the chart: https://bikeforums.net/showthread.php?t=316561&page=5
