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  1. #1
    madman
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    using triple crank as double?

    hi, I have an old fc-1050 105 triple I'd like to remove the granny on. Will this weaken the crank or can it handle it?

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    Senior Member barba's Avatar
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    Why would it weaken the crank? Is it on a bike set up as a triple?

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    madman
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    Quote Originally Posted by barba View Post
    Why would it weaken the crank? Is it on a bike set up as a triple?
    yeah...triple set up not much hills around here, anyway the granny ring seems to me like it plays part of the designs rigidity

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    Senior Member barba's Avatar
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    I don't think so. The granny ring typically bolts onto the crank in a different place than the two larger rings.

    Personally, I wouldn't bother. If you don't use it there really isn't any harm in just letting it sit there unused and you don't gain anything by removing it. Just get a double next time you buy a bike.

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    biked well well biked's Avatar
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    I have a bike that when brand new had a crankset that was drilled for three rings, but only had two installed. Talk about cost cutting measures.

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    madman
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    thanks for the advice, I'll just leave it, I just thought I was spinning it for nothing, but prolly only weighs 20 grams. lazy man here!

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    Quote Originally Posted by well biked View Post
    I have a bike that when brand new had a crankset that was drilled for three rings, but only had two installed. Talk about cost cutting measures.
    FSA actually makes some cranksets that are designed to be used for both triple and double application. Just remove the granny. Different BB of course due to chainline.

  8. #8
    Always find my way home
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    Quote Originally Posted by oilman_15106 View Post
    FSA actually makes some cranksets that are designed to be used for both triple and double application. Just remove the granny. Different BB of course due to chainline.
    More importantly, adjust FD limit so you don't drop a chain. If you really want to do this IDT a new BB is necc... If it shifted OK with the old BB the bike was set up with, why change it?
    "Send lawyers, guns, and money"

  9. #9
    Senior Member Bill Kapaun's Avatar
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    Quote Originally Posted by SCREEM View Post
    thanks for the advice, I'll just leave it, I just thought I was spinning it for nothing, but prolly only weighs 20 grams. lazy man here!
    I was thinking about leaving the granny ring off my bike last week when I was servicing the BB. I decided it was just easier to keep track of the parts if I left it on.

  10. #10
    Senior Member erader's Avatar
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    Quote Originally Posted by oilman_15106 View Post
    FSA actually makes some cranksets that are designed to be used for both triple and double application. Just remove the granny. Different BB of course due to chainline.
    couldn't you do this with any triple crankset ... remove the granny and shorten the BB spindle?

    ed rader

  11. #11
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    Quote Originally Posted by erader View Post
    couldn't you do this with any triple crankset ... remove the granny and shorten the BB spindle?

    ed rader
    you could in most cases but you have to be sure the bosses cast into the arms for mounting the granny ring don't get too close to the chainstays with the shorter spindle.

  12. #12
    WNG
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    Spin Forest! Spin! WNG's Avatar
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    I have an old Sugino crank of 110 BCD from a Giant bike that had arms with unthreaded holes in its spider for a granny ring. Also a new(er) Cannondale EX/PX double crank that came either double or triple. The double had the unused nubs still there.
    So, yes, it exists and won't weaken a crank to remove the granny ring.
    The 105 cranks were very good units anyway.

    But it really weighs about the same as a few wet napkins, so I'd simply leave it alone, unless you plan to go the nine yards and replace the BB spindle for a double unit. (tighter fit, more rigid, less agressive chainline)

    If it's just a matter of looks, whatever floats your boat, unbolt it and don't lose any of the pieces.
    The day you bonk, and face that last nasty climb, it's going back on there.

  13. #13
    madman
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    Quote Originally Posted by WNG View Post
    I have an old Sugino crank of 110 BCD from a Giant bike that had arms with unthreaded holes in its spider for a granny ring. Also a new(er) Cannondale EX/PX double crank that came either double or triple. The double had the unused nubs still there.
    So, yes, it exists and won't weaken a crank to remove the granny ring.
    The 105 cranks were very good units anyway.

    But it really weighs about the same as a few wet napkins, so I'd simply leave it alone, unless you plan to go the nine yards and replace the BB spindle for a double unit. (tighter fit, more rigid, less agressive chainline)

    If it's just a matter of looks, whatever floats your boat, unbolt it and don't lose any of the pieces.
    The day you bonk, and face that last nasty climb, it's going back on there.
    Bonk? I coast in to the closest donut shop far before bonking but yeah if I take it off I'll keep it safe in the parts pile, great advice all thanks.

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