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-   -   washer with a little hook in rear fork tracks (http://www.cyclebanter.com/showthread.php?t=255755)

Emanuel Berg[_2_] April 24th 18 01:58 AM

washer with a little hook in rear fork tracks
 
Many times I've seen washers with a little hook
to be used in rear triangle dropout tracks.
Those (the washers) are pretty big.

E.g. the Shimano Nexus 3 has them, often in
some bright color like yellow. They are between
the dome nut and the rear fork tracks.

What is the purpose of the little hook or
protruding part, and how is it different from
a regular washer with a rough pattern, pointing
into the frame?

We assume both are pulled 28Nm.

--
underground experts united
http://user.it.uu.se/~embe8573

Frank Krygowski[_4_] April 24th 18 02:18 AM

washer with a little hook in rear fork tracks
 
On 4/23/2018 8:58 PM, Emanuel Berg wrote:
Many times I've seen washers with a little hook
to be used in rear triangle dropout tracks.
Those (the washers) are pretty big.

E.g. the Shimano Nexus 3 has them, often in
some bright color like yellow. They are between
the dome nut and the rear fork tracks.

What is the purpose of the little hook or
protruding part, and how is it different from
a regular washer with a rough pattern, pointing
into the frame?

We assume both are pulled 28Nm.


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.

--
- Frank Krygowski

Emanuel Berg[_2_] April 24th 18 02:24 AM

washer with a little hook in rear fork tracks
 
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.


Okay...?

The surfaces are flat! But there is also the
hook! Perhaps the hook is just a way of putting
it (the washer) there so the flats align
easily? But somehow that sounds unlikely!

And what happens with the torque if there is an
ordinary washer?

--
underground experts united
http://user.it.uu.se/~embe8573

John B.[_3_] April 24th 18 06:02 AM

washer with a little hook in rear fork tracks
 
On Tue, 24 Apr 2018 03:24:40 +0200, Emanuel Berg
wrote:

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.


Okay...?

The surfaces are flat! But there is also the
hook! Perhaps the hook is just a way of putting
it (the washer) there so the flats align
easily? But somehow that sounds unlikely!

And what happens with the torque if there is an
ordinary washer?


Washers with the little "hook" are used in a number of devices as an
anti rotation system. The "hook" fits into a hole, or in the case of a
bicycle the rear dropout slots.

Do a google search for "anti rotation washer". There are literally
hundreds of different types.
--
Cheers,

John B.


Tosspot[_3_] April 24th 18 06:13 AM

washer with a little hook in rear fork tracks
 
On 24/04/18 02:58, Emanuel Berg wrote:
Many times I've seen washers with a little hook
to be used in rear triangle dropout tracks.
Those (the washers) are pretty big.

E.g. the Shimano Nexus 3 has them, often in
some bright color like yellow. They are between
the dome nut and the rear fork tracks.

What is the purpose of the little hook or
protruding part, and how is it different from
a regular washer with a rough pattern, pointing
into the frame?

We assume both are pulled 28Nm.


Anti rotation washer. The lug sits at various angles to the axle flats.
The colours indicate the angle. I have used white, red and green in
the past.

They work if the axle nut comes loose.


Emanuel Berg[_2_] April 24th 18 07:07 AM

washer with a little hook in rear fork tracks
 
Tosspot wrote:

Anti rotation washer. The lug sits at various
angles to the axle flats. The colours
indicate the angle. I have used white, red
and green in the past.

They work if the axle nut comes loose.


Amazing!

--
underground experts united
http://user.it.uu.se/~embe8573

Frank Krygowski[_2_] April 24th 18 03:19 PM

washer with a little hook in rear fork tracks
 
On Monday, April 23, 2018 at 9:24:43 PM UTC-4, Emanuel Berg wrote:
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.


Okay...?


To further explain the torque:

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.).


The surfaces are flat! But there is also the
hook! Perhaps the hook is just a way of putting
it (the washer) there so the flats align
easily? But somehow that sounds unlikely!

And what happens with the torque if there is an
ordinary washer?


I think there may be no problems with an ordinary washer, provided the nuts
holding the axle in place are tight enough. In that case, the torque will be
transmitted to and from the dropouts by the friction forces between the nuts and
dropouts.

With the washer, the axle flats transmit torque between the axle and the washer,
and the washer's tabs transmit torque between the washer and the dropouts,
helping the axle nuts transmit torque.

- Frank Krygowski

Emanuel Berg[_2_] April 25th 18 02:24 PM

washer with a little hook in rear fork tracks
 
Frank Krygowski wrote:

We engineers would say [,..]


We long-ears would say, that while there are
many internally geared hubs w/o non-turn
washers (e.g., Duomatic and Dreigang/Triplex),
it is possible that development has moved
forward and that the Shimano Nexus 3 has them
(non-turn washers) to counteract the increased
torque, compared to a single speed hub.

BTW Nexus 3 has a break arm to.

--
underground experts united
http://user.it.uu.se/~embe8573

AMuzi April 25th 18 03:34 PM

washer with a little hook in rear fork tracks
 
On 4/25/2018 8:24 AM, Emanuel Berg wrote:
Frank Krygowski wrote:

We engineers would say [,..]


We long-ears would say, that while there are
many internally geared hubs w/o non-turn
washers (e.g., Duomatic and Dreigang/Triplex),
it is possible that development has moved
forward and that the Shimano Nexus 3 has them
(non-turn washers) to counteract the increased
torque, compared to a single speed hub.

BTW Nexus 3 has a break arm to.


Fichtel & Sachs Duomatic has a brake arm. Torpedo Dreigang
has a flatted axle with no-turn washer.

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



Emanuel Berg[_2_] April 25th 18 04:29 PM

washer with a little hook in rear fork tracks
 
AMuzi wrote:

Fichtel & Sachs Duomatic has a brake arm.
Torpedo Dreigang has a flatted axle with
no-turn washer.


Ha ha! :)

Torpedo 3 has no-turn washers in the
flat axle/washer sense but not with the little
hook that the Shimano Nexus 3 no-turn
washers have.

And Dreigang has a brake arm as well! :)

--
underground experts united
http://user.it.uu.se/~embe8573


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