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Rear derailleur questions

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Rear derailleur questions

Old 12-02-12, 11:24 AM
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Rear derailleur questions

I am currently building up a 1x10 cross bike and had some questions about which kind of rear derailleur I should order. Most questions about the chain wrap capacity and stuff. I plan on running a 42T chainring in the front and either a 11-30T or 11-32T cassette in the back. Would a rear derailleur with a chain wrap capacity of 35T do the trick or do I need one wit more capacity? Thanks!
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Old 12-02-12, 11:55 AM
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Chain wrap involves the sum of the differences of the largest and smallest sprockets front and back, ie. 53-39 and 11-26 = 14+15 or 29t total.

Since you're building a 1x10, you only look at the cassettes range or 22t. That's well within the range of short cage RDs, so you can use anything you want, including one with 25t capacity.

I prefer using the shortest cage possible (or what I already have) for a variety of minor reasons, so if you're buying new, and have no intention of ever going double up front, consider a shorter cage RD, provided it's compatible with a 32t rear sprocket.
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