Chain tension question- Mtbr.com
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  1. #1
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    Chain tension question

    I just converted my Orbea Alma to a single speed. I went for it without using a tensioner and am using a half-link to get the chain to the right tension. After trying 32X16, 32X18 I could not get the tension right but with a 32X17 the chain fit pretty well. My only concern is the chain is really tight (cranks don't move too freely) is this a big problem? will it be ok once the chain stretches out a little? I might go try 32X19 to get a better tension but that is a little too easy of a gear. Any help would be appreciated.

  2. #2
    mtbr member
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    A search for magic gear calculator finds this

  3. #3
    PSYCHOLUST
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    Just a note on the MAGIC gear..... I measured up my old hardtail and fed in the stats and TA-DA, I had a pretty good ratio that worked........ A few months later I measured the chainstay length on my girlfreinds old Giant XTC and ABSOLUTELY NOTHING workable was any good......................... The calculator is a dead on awsome tool, but some frames (chainstay length actually) just don't work......

    Give it a try

  4. #4
    mtbr member
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    Quote Originally Posted by scyule
    Just a note on the MAGIC gear..... I measured up my old hardtail and fed in the stats and TA-DA, I had a pretty good ratio that worked........ A few months later I measured the chainstay length on my girlfreinds old Giant XTC and ABSOLUTELY NOTHING workable was any good......................... The calculator is a dead on awsome tool, but some frames (chainstay length actually) just don't work......

    Give it a try
    Ok so I plugged in some numbers... The gear ratio I want is about halfway on/halfway off to the left of the highlighted area. Is that alright or does it have to be dead on? I can live with a little imperfection.

  5. #5
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    I can live with a little imperfection.
    You might not be able to live with a little imperfection. Nothing worse than digging hard to get up a hill and have your chain come off. Faceplant city...
    I'm super, thanks for asking...

  6. #6
    one chain loop
    Reputation: fishcreek's Avatar
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    left of the shaded area is tight and the right side is loose. it just gives you a rough idea on what combos will work in your chainstay length but will still vary depending on your drivetrain wear and if you measused your chainstay length accurately. you still have to try it out yourself.
    everything sucks but my vacuum cleaner.

  7. #7
    local trails rider
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    Quote Originally Posted by seppk
    My only concern is the chain is really tight (cranks don't move too freely) is this a big problem? will it be ok once the chain stretches out a little?
    Sounds a bit tight: it loads the bearings. I wouldn't use it like that.

    On my pavement bike, 36/16 was too tight with a new chain, so I used 36/15 which was loose enough to need a tensioner. Now I have some worn parts, including a chain that has seen some use, and 36/16 is perfect.

  8. #8
    SS or Die
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    No matter what works initially, will fail once the chain stretches unless you intend changing the chain on a regular basis. Although I too prefer the clean look of the magic gear result but the use of a light weight tensioner would allow you to use the correct gearing for the sake of about 100grams and take up any unwanted slack along the way.

    I used a Yess BB tensioner on my Salsa Mamasita for a while and you cant even see it unless you look really hard. It only weighed 100 grams and I didnt even notice it. In your case your frame is 300 grams lighter than mine was also.

    Cheers.
    "Be the Gear..."

  9. #9
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    Like he said, tension will become an issue as the chain wears, and too tight a chain will eat bearings. Excellent tensioning options:
    Forward Components EBB
    White Eno Eccentric hub

  10. #10
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    Quote Originally Posted by lunatic fringe
    Nothing worse than digging hard to get up a hill and have your chain come off. Faceplant city...

    Been there, Done that!!!

  11. #11
    Mtbr Forum Sponsor - Homebrewed Components
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    we just converted my buddy's orbea alma and found that 32/20 was the magic gear for him. Granted, his bike was a 29er, not sure about yours. The chain was ever so slightly tight, but the crank spun freely, and everytime he pedaled (even on the flats) some slack appeared in the chain (i can see it when i followed him). It's also a new chain, so when it stretches out a hair, it should be perfect.
    On a side note, the Paul Melvin would not work on his bike at all. There is no way to get the wheel on or off with the Melvin installed. And we tried without the chain on, so it wasnt even that.

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