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  1. #1
    Senior Member Thumpic's Avatar
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    So why do Suntour barcon shifters incorporate a left hand mounting screw?

    I consider myself (obviously mistakenly) a pretty bright guy. But I cannot figure out the advantage to tightening a barcon with counterclockwise torque.

    Thumpic....

    Green is the new "CHEAP"

  2. #2
    Stop reading my posts! unworthy1's Avatar
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    when you see how it works: it's just a regular flat-head type bolt that uses that head to expand the wedges that tighten against the insides of the bar, but you are tuning it from the "wrong end" so the action is reversed from normal. It's not actually LH thread, just RH and screwed from the abnormal end. So, much easier and cheaper for SunTour (or anybody) to source that "normal" bolt.

  3. #3
    DRF aka Thrifty Bill wrk101's Avatar
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    +! Its not left handed if you approach it from the opposite end.

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    Senior Member Thumpic's Avatar
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    Oh yeah!!! They are in great shape so I didn't completely disassemble them. I may have realized how they worked....
    Thumpic....

    Green is the new "CHEAP"

  5. #5
    Can'tre Member 3alarmer's Avatar
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    .
    ...your other left.
    Quote Originally Posted by CKey_Cal View Post
    Facts are binary. If they aren't, then they aren't facts.

  6. #6
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    I figured this diagram would help, the screw in question is #19 :


  7. #7
    Senior Member Thumpic's Avatar
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    Quote Originally Posted by Metacortex View Post
    I figured this diagram would help, the screw in question is #19 :

    Outstanding!! Diagrams are great!
    Thumpic....

    Green is the new "CHEAP"

  8. #8
    rhm
    rhm is online now
    multimodal commuter rhm's Avatar
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    So the real question is why Suntour barcons don't have a left handed thread! But the answer I think is because this is how earlier barcons (i.e. Campy) were made. I'm not sure how Cyclo barcons were done.

  9. #9
    Stop reading my posts! unworthy1's Avatar
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    I'm not sure if it's cheaper for a manufacturer to stick with the more common conventional threading for the bolt as well as the body (or "frame", part #13 ) but since it's a unique product they could have chosen to use LH threads for both and the shade-tree mechanic would not have to go against his instincts when mounting the unit. However, I'm glad they chose not to since if you ever have to repair one of these (instead of scrapping it) due to stripped threads it might be much easier to find a RH thread Helicoil, or even a kludge using a flat head bolt with a slot cut in the small end.

  10. #10
    DRF aka Thrifty Bill wrk101's Avatar
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    FWIW, I just removed a Simplex set of bar ends, and I turned the bolt the normal direction (lefty loosy). Gave it a quick turn to the right, and it was really tight. So I stopped and turned it left instead. It also took a 5mm allen, instead of a 6mm allen like the Suntour and Shimano bar end shifters.

  11. #11
    coprolite fietsbob's Avatar
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    yes the head of the bolt is facing away from you , to you flip your thinking around..



    + when doing wheel truing, on the bike , you think the same inverse way ..

    when the head of the Nipple is facing away from You Too , reaching past the hub . not with the spoke right in front of you.

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