1. The most important thing about buying a new bike is to make sure it fits. The only way you'll know if the bike is right for you is to size up the bike and make sure that the bike's geometry matches your body's geometry. Ask questions and do some research.
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2. If possible, try to find a shop that will let you demo the bike on real dirt. Five minutes in a parking lot won't cut it. You wouldn't buy a car without a real world test drive, and a bike should be no different.
3. Don't belive the hype. Just because your favorite rider or best friend rides a certain bike, that doesn't mean that's the best one for you. Have an open mind and be realistic about your needs and ability.
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  1. #1
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    Rear Derailleur ??

    I'm new to MTBs and broke my rear derailleur on my 9 speed bike. It was an XTR M972 Shadow Carbon Fiber derailleur. It appears to have been a long cage one (not sure though). I was wondering if I can replace it with a medium cage derailleur of the same type ?????

  2. #2
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    It depends on the cassette,they are designed to handle a number of teeth. The long cage can take up to around 36 teeth ,go to the shimano site it will tell you how many teeth the med. cage can handle.

  3. #3
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    Re: Rear Derailleur ??

    You need to calculate capacity. Subtract your smallest cog number from largest cog number, then subtract smallest chainring from largest. Add the two numbers together and derailleur capacity needs to be same or larger. Ex: 34-11=23, 44-22=22, 23+22=45 minimum capacity.

    Sent from my DROID RAZR using Tapatalk 2

  4. #4
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    Re: Rear Derailleur ??

    Med cage xtr has 35t capacity.

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  5. #5
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    When to use a Long Cage vs Short Cage Derailleur?

    If you are truly running 9 speed - 1X9 then a short cage will work.

  6. #6
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    Here's what happens if you under spec the derailleur capacity by using a medium where a long cage was. If you shift the front crankset into the small ring and the rear cassette into the smallest cogs it will not have the range to take up the slack of the chain. So it will not work but it will not easily snap the chain.
    Since no one uses that combination EVER you don't need a derailleur to be able to handle it.
    This is considered advanced drive train use so choose it at your own risk.

  7. #7
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    Thanks for the replies. I got a better grip on this, but here's my set up just in case....jajaja.
    Cassette 12-27 Crankset 22/32/44
    So not so sure if its a good idea !! Specially for a rookie like me. What do you all think? I would just really love the extra clearance, as I ride trails with some large rocks and apparently avoiding them is not as easy as I thought. These darn derailleurs aren't cheap !!

  8. #8
    IoC
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    Quote Originally Posted by Luis M. View Post
    I would just really love the extra clearance, as I ride trails with some large rocks and apparently avoiding them is not as easy as I thought. These darn derailleurs aren't cheap !!
    You might want to look at getting an XT derailleur instead of XTR: they're about half the cost and not even 10% heavier.

  9. #9
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    Quote Originally Posted by Luis M. View Post
    Thanks for the replies. I got a better grip on this, but here's my set up just in case....jajaja.
    Cassette 12-27 Crankset 22/32/44
    So not so sure if its a good idea !! Specially for a rookie like me. What do you all think? I would just really love the extra clearance, as I ride trails with some large rocks and apparently avoiding them is not as easy as I thought. These darn derailleurs aren't cheap !!
    I have 37T difference too (26/40 + 11/34)= 14+23 and am running with a medium XT shadow plus. (m786)

    As long as I dont use 26/11 it is fine. (use at your own risk)

    The XT m786 typical price is about $100, but I have seen it for as low as $70 at blueskycycling. Right now they are 104. The SLX (Which is fine) is running $70

  10. #10
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    You could use a medium but I think I'd go with a long in case you want to change that cassette.

  11. #11
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    Thanks again guys. Gonna stick with the long (this time), being that I found it brand new for $136.00 online. If I brake it again I'm selling my 3 ring Crankset and going double for the swap to med.

  12. #12
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    But XTR isn't printed on it!

    Quote Originally Posted by IoC View Post
    You might want to look at getting an XT derailleur instead of XTR: they're about half the cost and not even 10% heavier.

  13. #13
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    Quote Originally Posted by Shibby View Post
    But XTR isn't printed on it!
    Funny how they get us with the labels !! Definitely XT if it happens again...lol. My pockets aren't that deep.

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