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#1
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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 |
#2
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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 |
#3
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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 |
#4
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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. |
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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 |
#6
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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 |
#7
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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 |
#8
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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. |
#9
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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 |
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