What cage length?- Mtbr.com
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  1. #1
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    What cage length?

    How do I know what cage length I need? What is it based on? Cassett size?

    Thanks,
    TBob

  2. #2
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    Quote Originally Posted by TBob
    How do I know what cage length I need? What is it based on? Cassett size?

    Thanks,
    TBob
    usually the number of rings your running. With 3 rings is safer to go with a long cage, but for 2 or single rings a short cage is nice although not necessary

  3. #3
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    Quote Originally Posted by zedro
    usually the number of rings your running. With 3 rings is safer to go with a long cage, but for 2 or single rings a short cage is nice although not necessary

    Thanks!

  4. #4
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    Zed is right, but don't forget about suspension travel. I see so many bikes that are on the verge or ripping off their derailleur. If you set your bike on the ground with the chain in the big gear/cassette and big ring/front, your derailleur should not be pulled tight. If so, when the suspension travels upwards two things happen. Your chain/derailleur is limiting your suspension travel, and your derailleur is stretched beyond it's means.

    Guess what's going to win that battle? The bike and the chain, not the derailleur. I've had to re-tap derailleur hangers because the mech was ripped right out of them.

    Usually on a DH rig, a medium cage is fine as long as you have enough chain length. But a lot of bikes now are coming with dual ring systems up front. So depending on how big your cassette is, you should go with a long cage.


    Quote Originally Posted by TBob
    Thanks!

  5. #5
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    Quote Originally Posted by Eagle1
    Zed is right, but don't forget about suspension travel. I see so many bikes that are on the verge or ripping off their derailleur. If you set your bike on the ground with the chain in the big gear/cassette and big ring/front, your derailleur should not be pulled tight. If so, when the suspension travels upwards two things happen. Your chain/derailleur is limiting your suspension travel, and your derailleur is stretched beyond it's means.

    .
    heh, i was debating weither to mention that, but usually people dont catch on to it anyways (ok, by people i mean Bullit riders ).

    Higher pivots will stretch the derailler out more on compression. This can be counter-acted by using a chainguide and setting the lower pulley as high as possible. Frequently i see pics here of Bullits with an MRP set way too low, then i hear compaints of crappy or ghost shifting (because the derailler is getting too much action through the travel). But then i mention it and they get all mad and huff about how they just wanted people to say how rad their bike is........sigh

  6. #6
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    Hah, I learned that from my Super-8 with an MRP. I first thought is was because of my chain line when I switched to Razor Rock rearend. But if anything that made the chain line better going back to a 135mm spacing instead of 150mm. I soon realized it was that top pully grabing the chain. So I rotated the boomerang to the 12 o'clock position and waa-laa, no more goofy shifting.

    Funny how most of this stuff can be figured out if you just step back and take a good look!






    Quote Originally Posted by zedro
    heh, i was debating weither to mention that, but usually people dont catch on to it anyways (ok, by people i mean Bullit riders ).

    Higher pivots will stretch the derailler out more on compression. This can be counter-acted by using a chainguide and setting the lower pulley as high as possible. Frequently i see pics here of Bullits with an MRP set way too low, then i hear compaints of crappy or ghost shifting (because the derailler is getting too much action through the travel). But then i mention it and they get all mad and huff about how they just wanted people to say how rad their bike is........sigh

  7. #7
    cmd
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    Quote Originally Posted by zedro
    Higher pivots will stretch the derailler out more on compression. This can be counter-acted by using a chainguide and setting the lower pulley as high as possible. Frequently i see pics here of Bullits with an MRP set way too low, then i hear compaints of crappy or ghost shifting (because the derailler is getting too much action through the travel). But then i mention it and they get all mad and huff about how they just wanted people to say how rad their bike is........sigh
    So, can I run a road derailler(short cage) on my bullit? I am running a SRS right now.

  8. #8
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    Quote Originally Posted by cmd
    So, can I run a road derailler(short cage) on my bullit? I am running a SRS right now.
    with a single ring you'lll be ok. Just set the roller up as far as possible, and set the chain length with the suspension at full compression.

  9. #9
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    Quote Originally Posted by Eagle1
    Zed is right, but don't forget about suspension travel. I see so many bikes that are on the verge or ripping off their derailleur. If you set your bike on the ground with the chain in the big gear/cassette and big ring/front, your derailleur should not be pulled tight. If so, when the suspension travels upwards two things happen. Your chain/derailleur is limiting your suspension travel, and your derailleur is stretched beyond it's means.

    Guess what's going to win that battle? The bike and the chain, not the derailleur. I've had to re-tap derailleur hangers because the mech was ripped right out of them.

    Usually on a DH rig, a medium cage is fine as long as you have enough chain length. But a lot of bikes now are coming with dual ring systems up front. So depending on how big your cassette is, you should go with a long cage.
    After having my derailler pulled into my rear spokes many times by a loose chain and long cage, I've got to recommend a short cage/short chain setup for freeriding of any type. When a big impact hits the bike, the chain and derailluer tend to wiggle around and a long cage is more likely to be pulled into the spokes by a chain touching the rear tire and being pulled in. Shorter chain=more tension=less movement on drops and less likely that the chain will be sucked into the tire, and subsequently the derailluer into the spokes.

  10. #10
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    Well yesterday my XT snapped at a pivot and was flung into my spokes, thus taking out all of my drive side spokes, and maybe even killing my King hub... My cassette is DOA and the chain is non exsistant anymore... I just hope I didn't bend my chain ring or chain guide...

    I prolly just didn't have enough chain length...

  11. #11
    cmd
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    Quote Originally Posted by zedro
    with a single ring you'lll be ok. Just set the roller up as far as possible, and set the chain length with the suspension at full compression.
    What is the cheapest way to go for a quality road derailler? The cheaper the better, and can I run my same 9spd cassette and shifters?

  12. #12
    LT1
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    Shimano 105 is relatively inexpensive...

    ...it's like the Deore or LX of road bikes. Yes, you can use your same Shimano mountain shifters and yes, you can run all nine speeds, too, so long as you follow the chain length issues already mentioned.

    I run a mid cage XTR on a 38T single front ring with an 11-30 8 speed cassette, no problem.

  13. #13
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    Quote Originally Posted by cmd
    What is the cheapest way to go for a quality road derailler? The cheaper the better, and can I run my same 9spd cassette and shifters?
    Get a 105 shortcage, it works great with any and all MTB cassettes/shifters (shimano compatible shifters, that is). Usually around $30 online.

    Beware of the guys who worship the Shimano bible and say a 105 won't work with "any" cassette - it does. Yes, including a 11-34.

    If you have a ton of chain growth in your rear suspension, the spread of your cassette may or may not be an issue; on my RFX with a 22-36 it is not. I imagine a single-ring Bullit should be able to use pretty much any cassette range.
    ~~HCOR.net~~
    East Coast, beyotch!

  14. #14
    cmd
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    OK LBS says no

    Quote Originally Posted by sub6
    Beware of the guys who worship the Shimano bible and say a 105 won't work with "any" cassette - it does. Yes, including a 11-34.
    So the LBS says no, he says with a 11-34 it would push it too much. He said it might break the derailler. Could it be pushing it too much? Should I just try to find an shortcage XT. Or just go for a medium cage. Can't change cassette, i am not that strong of a peddaler.

    Thanks

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