Re: [CR] Crank cotter filing, now cotter direction

(Example: Humor:John Pergolizzi)

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Date: Sat, 15 May 2010 06:24:26 -0400
From: "Ken Freeman" <kenfreeman096@gmail.com>
To: Derek Athey <devondirect@googlemail.com>
Cc: classicrendezvous@bikelist.org
Subject: Re: [CR] Crank cotter filing, now cotter direction


So this convention means that when either pedal is rising on an upstroke, the round end of the cotter pin is visible from above?

On Sat, May 15, 2010 at 5:01 AM, Derek Athey <devondirect@googlemail.com>wrote:
> John
>
> I don't accept that reasoning. Because the left side isn't under stess due
> to it being on the 'rise' when the load is on the right side. All complete
> machines sold in th UK when cotters were current had them with the heads
> leading. 'If it ain't broke...don't fix it!'
>
> Derek Athey
> Honiton, Devon UK
>
> On Sat, May 15, 2010 at 12:55 AM, John Betmanis <johnb@oxford.net> wrote:
>
> > On 14/05/2010 5:30 PM, Derek Athey wrote:
> >
> > The 'head' of the cotter always 'leads' the stoke, thereby giving the
> >> strongest point of energy on the down stroke using the strongest point
> >> of the cotter against the flat of the axle to reduce stress.
> >> That way one also ensures that the cranks align perfectly.
> >>
> >
> > Derek, that does make sense, although they would be perfectly aligned
> > either way, provided both sides are the same direction. However, I just
> did
> > an image search and still see it both ways. In fact, one image was on
> > Sheldon Brown's site, where he says this:
> >
> > "Some older books speak of installing the cotter so that the pedaling
> load
> > is taken by the thick end of the cotter. This is an error, because if you
> do
> > the right side that way, the left side will be stressing the thin end,
> and
> > vice versa. It really doesn't matter which way you put them in, as long
> as
> > they face in opposite directions."
> >
> > His reasoning is correct, because it's only the *left* crank that
> transfers
> > load to the BB axle, then the axle transfers it to the right crank and
> > chainwheel, through the *thinner* end of the cotter pin.
> >
> > --
> > John Betmanis
> > Woodstock, Ontario
> > Canada
> > _______________________________________________
> >
> _______________________________________________
>

--
Ken Freeman
Ann Arbor, MI USA