Hey Thanks Steven ,
Somehow I'd failed to look at it that way . Explains it very well . Chain stiffness !
And it certainly helps explain why the first cable-operated derailleurs were for :
3-speeds with 1/8 chain
4-speeds with 3/32 chain
I've always winced at the thought of trying to put very much side to side deflection on a 1955 1/8 inch chain !
Raoul Delmare
Marysville Kansas
> Marcus wrote:
>
> > I know most of the literature says don't use the small-small or big-big
> > combinations. Doesn't this generally refer to triples and/or modern
bikes
> > with wider spacing? I would think that on bikes in the CR timeframe,
with
> > double chainrings, cross-chaining would not be as big of an issue,
unless
> > the chainstays were really short.
>
> Actually the crossing on older bikes was far more problematic than with
new
> bikes. Modern chains are now so flexible that most can handle quite severe
> sideways bending, something that was definitely not possible in the
classical
> era. As the chains didn't flex, this meant extreme pressure on the teeth
of
> both chainrings and freewheel. Friction derailleurs on the other hand do
make
> keeping derailleurs in check with extreme angles easier.
>
> Steven Maasland
> Moorestown, NJ