On 4/25/2018 12:36 PM, Emanuel Berg wrote:
AMuzi wrote:

There are several ways to extend axle flats
with a no-turn washer. None work any better
than the others.

The reason to do it is

1) to keep it all together

and

2) if it gets loose, it won't get *that* loose?


23 April, in the first reply of this thread, Frank Krygowski
wrote:

"Internally geared hubs exert torque on the bike frame or
dropouts in certain gears. If the axle has flat surfaces and
the washer's inner hole has matching flats, I think the
washers you describe are a way the hub transmits that torque
to the frame."

With the patience of a saint, Mr Krygowski expanded on that
in his reply 24 April:

"With a derailleur hub or a single speed hub, the torque
applied to the wheel
by the chain and sprocket is the same value as the torque
applied by the
tire's friction force acting on the tire+wheel radius. Of
course, the dirctions
are opposite. We engineers would say the sum of the
torques must be zero, at
least for constant velocity situations.

When you shift an internal gear hub to a lower gear, the
gear hub applies more
torque to the wheel than is applied by the chain and
sprocket. That must be
generated by a reaction torque from the dropouts (or on some
hubs, from a
reaction arm attached to a chainstay, etc.). "


People have devised different styles to do that:
https://www.bicyclehero.com/media/ca...d/8/4/8475.png

http://images.modernbike.com/256/main_2126212142.jpg

https://fasterbikes.eu/738-thickbox_...pare-parts.jpg

http://www.ucycle.com/merchant/2856/.../Capture47.PNG

and of course the original design:
http://i.ebayimg.com/17/!BnNUOswCGk~$%28KGrHqUOKicEtluYLPB6BLio-KnEdQ~~_35.JPG


the exact shape doesn't matter except where axle-to-frame
position is critical, such as inside-cable designs like this:
http://cdn.modernbike.com/Product_Im...arge_49040.jpg

which are color-coded for various angles.




--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971