Oh, the shame! Firstly to have the hubris to correct Sheldon, and then to be called to account by the builder of the one of the coolest frames ever featured in Bicycle Guide, Mr Big Ti Head himself! Mark, you are totally correct. I have been labouring under the misapprehension that a right hand Suntour bar cons has a left hand threaded expander bolt ever since I bought my first pair in 1988. I'm not worthy! I'm not worthy! I'm not worthy! I'm not worthy! I'm not worthy! I'm not worthy! I'm not worthy! I'm not worthy! I suck!
Best Wishes, DB
Mark Bulgier wrote:
> Sheldon Brown wrote:
>
> > > In the case of non-indexed bar-end shifters, there's no
> > > such thing as a "front" or "rear" they're just shifters.
>
> and David Benson replied:
>
> > While this is true if we only consider gear shifting
> > capability, the right hand lever in a set of Suntour
> > bar cons has a left hand threaded expander bolt.
> > In a crash, this allows the lever to be loosened by a
> > sidewards impact, reducing the chance that the lever
> > will be broken off.
>
> Dave, do you have one like that now, or is this from memory? 'Cuz I have
> installed and/or worked on many (maybe a hundred or two) Suntour Bar-cons,
> and never saw one with a left-hand thread.
>
> I have run into many people who think they're *all* left-hand threaded,
> because you turn them clockwise to loosen. This seems backwards until you
> get it apart and see how they're made, then the logic of it becomes clear.
> (see footnote below if you want my explanation)
>
> You're right that a left-hand thread on the right shifter would cause it to
> loosen in a crash - and not be left behind, which just ain't right! I've
> just never seen this or heard of it before now. And what with the history,
> of so many people thinking barcons are *all* left-threaded, I'm skeptical.
> But eager to be proven wrong, because that would be a cool feature!
>
> So do you have a pair where you turn one CW and the other CCW to tighten?
>
> Mark Bulgier
> Seattle, Wa
> USA
>
> Footnote:
> Tightening a right-hand threaded bolt usually means the bolt moves *away*
> from you. If the head is on your side of the bolt as it normally is, the
> head moves towards the work and tightens. On the bar-con though, the "head"
> is on the backside, and you're cranking on the end opposite the head (the
> tail?). It still moves away from you, but that makes the head move away
> from the work and loosen.