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  1. #1
    808+909 = Party Good Time
    Reputation: chumbox's Avatar
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    Whats the diff between long cage, medium cage and rapid rise?

    What benefits or short fallings do they all offer?

  2. #2
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    Long-cage derailleurs have more distance between the pulleys than medium-cage, allowing them to take up more chain slack. If you only have one or two chainrings, you can probably use the medium-cage, but if you have three chainrings and the usual wide-range cassette, then long-cage will be more suitable. The longer cage is very slightly heavier and rides a little closer to the ground, reducing obstacle clearance a little bit if the cage is, in fact, pointing downward.

    RapidRise derailleurs are sprung so that they "home" on the largest cog on the cassette, not the smallest. I think the theory behind RapidRise was that you could force-feed upshifts to smaller cogs instead of relying on your derailleur's parallelogram spring to upshift when you let out a click's worth of cable at the shift lever. RapidRise or non-RapidRise is your personal preference, as are the dual-control STI-style shifters that Shimano intends to be especially good with RapidRise (these shifters use the brake-lever blade as a sort of "paddle shifter").

  3. #3
    808+909 = Party Good Time
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    Thanks mechbgon, great info.

  4. #4
    pedal pusher
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    OMG, a helpful answer on the drivetrain forum.

  5. #5
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    Quote Originally Posted by f3rg
    OMG, a helpful answer on the drivetrain forum.

    Yeah seriously! Someone should flame this guy for asking an intelligent question and for getting an intelligent answer on mtbr.com. Just to keep it feeling normal....



    On a serious note, I'm running a medium cage on my XT crank and SRAM PG990 rear casette with no problem. Rapidfire shifters too.

  6. #6
    ~Disc~Golf~
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    I think where rapid-rise really shines is when its paired up with twist shifters. You can down-shift so friggin quickly
    Yup...That's how I roll
    Honestly... ahh I give up

  7. #7
    Doctor
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    I think the theory behind RapidRise was that you could force-feed upshifts to smaller cogs instead of relying on your derailleur's parallelogram spring to upshift when you let out a click's worth of cable at the shift lever.

    Agreed. The reason I gave up on RR was my preference of being able to "force" the shift to the larger rear cogs, not as it is in RR. I don't race, so I find myself demanding a shift when I need more power, not more speed.

    (I actually switched to SRAM X-9, but that's another story.)

    jeff

  8. #8
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    Actually the manufacturer publishes a "Total Capacity" for a derailleur in the specs. The capacity is calculated by subtracting the smallest chain ring from the largest plus the difference between the smallest cog on the cassette from the largest. On a standard 22/32/44T crankset with an 11/34T cassette The calculation is as follows:

    (44-22) + (34-11) = 45

    So with this combination you require a 45T capacity derailleur. Most medium cage derailleurs have 33T capacity. If you rings and cassette work out to more than 33 you need a long cage.

    Ronnie.
    The trouble with having an open mind is that people will insist on trying to put things in it.

  9. #9
    squish is good
    Reputation: Clutchman83's Avatar
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    Quote Originally Posted by Ronnie
    Actually the manufacturer publishes a "Total Capacity" for a derailleur in the specs. The capacity is calculated by subtracting the smallest chain ring from the largest plus the difference between the smallest cog on the cassette from the largest. On a standard 22/32/44T crankset with an 11/34T cassette The calculation is as follows:

    (44-22) + (34-11) = 45

    So with this combination you require a 45T capacity derailleur. Most medium cage derailleurs have 33T capacity. If you rings and cassette work out to more than 33 you need a long cage.

    Ronnie.
    Thats calculating for optimal range on the rear derailleur. A medium cage can work well on a triple ring with 11-32t setup, just won't work as well as a long cage.

    Personally I look at it this way, long cage for a 22-33-44 + 11-34 max gear combo. Medium cage for dual ring setup, anything reasonable. Short cage for dual ring front (22-36 max) 11-34 max cassette, or single ring + any cassette setup. The short cage is pushing it with a 36 crank to 34 cassette setup but it can work if adjusted properly though should be avoided as it's a stupid gear ratio to be using. I always go for the smallest derailleur I think I can get away with. Less weight is nice but more spring tension results in crisper shifts, wear and tear is a non-issue to me as I tend to break derailleurs on a yearly to bi-yearly basis.

    Rapid rise is personal choice. I have a rapid rise shifter/derailleur on one of my bikes, it's okay. I prefer the regular shifting configuration to be honest.
    Bike good, work bad.

  10. #10
    Bicyclochondriac.
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    Quote Originally Posted by Clutchman83
    Personally I look at it this way, long cage for a 22-33-44 + 11-34 max gear combo. Medium cage for dual ring setup, anything reasonable. Short cage for dual ring front (22-36 max) 11-34 max cassette, or single ring + any cassette setup. The short cage is pushing it with a 36 crank to 34 cassette setup but it can work if adjusted properly though should be avoided as it's a stupid gear ratio to be using. I always go for the smallest derailleur I think I can get away with. Less weight is nice but more spring tension results in crisper shifts, wear and tear is a non-issue to me as I tend to break derailleurs on a yearly to bi-yearly basis.
    .
    Do you mean a 22-36 double crank?

  11. #11
    squish is good
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    Quote Originally Posted by kapusta
    Do you mean a 22-36 double crank?
    Yes.
    Bike good, work bad.

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