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Old 11-14-10, 05:47 AM   #1
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44T front derailleur with 48T (M771 MTB)

Hi all,

quick question for anyone with experience/knowledge on this - I ordered a Shimano XT M771 dual pull front MTB derailleur - the website at the bike shop said it was 44/48T compatible.

Just installing it now and reading the instructions that came with it, I noticed the M771 says 44T only (and my front big chainring is 48T - m770 series). Is this actually an issue? Should it be fine, or should I expect issues, and if so, what are they? Is there a workaround?

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Old 11-14-10, 09:14 AM   #2
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If it is indeed designed for a 44T maximum chainring the curve of the cage will be a bit tight for a 48T so you will have to mount it higher than optimum to clear the ring. Shifting should be ok if not perfect. Just mount it as close to the big ring as you can and see how it works.
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Old 11-14-10, 11:19 AM   #3
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arc of outside plate of derailleur will rise in the center as it is made to go with a smaller radius..

circumference of chainring 44> 48 1/2 inch pitch teeth, is about a 2 inch difference..

a front derailleur for a 'Trekking/Touring' crankset will anticipate a 48t outer ring.
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