New bike build
07-18-20, 06:13 PM
#76
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Tires are mounted on rims looking good! I am looking at Derailleurs, running a 30/11 cassette and 2 speed front. What's the difference between the short and long cage and which do I need?
07-18-20, 09:18 PM
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Short and long cage has to do with the maximum capacity you can have to accommodate the chain wrap.
The formula is (large cog - small cog) + (large chainring - small chainring).
So for an 11-30 with a 50/34:
(30 - 11) + (50 - 34) = 19 + 16 = 35.
You need a rear derailleur with a capacity of 35 that can take a max cog of 30.
John
The formula is (large cog - small cog) + (large chainring - small chainring).
So for an 11-30 with a 50/34:
(30 - 11) + (50 - 34) = 19 + 16 = 35.
You need a rear derailleur with a capacity of 35 that can take a max cog of 30.
John
07-18-20, 10:06 PM
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O.K. I'm seeing that but do not comprehend what it means, capacity of 35 what, teeth? And I have a 30 cog so I am good there but what do you look for when you buy one? Is all that stuff on the package? Do I need a short, med, long?
07-18-20, 10:49 PM
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You can find the specs on the derailleur that will give you the max cog and capacity.
It works this way. The wider range of gearing (11-30 & 50/34) you have requires a longer the cage. Basically you need more chain to cover the smallest to largest cogs and chainrings. That chain has to go somewhere. The longer cage holds the extra chain needed when you shift to a larger cog and chainring.
John
It works this way. The wider range of gearing (11-30 & 50/34) you have requires a longer the cage. Basically you need more chain to cover the smallest to largest cogs and chainrings. That chain has to go somewhere. The longer cage holds the extra chain needed when you shift to a larger cog and chainring.
John
