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[Closed] What is the idea behind these cranks please ?

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[img] [/img]My mates mother in law found these lurking at the back of her attic.
Anybody know what is the idea with the arms being that shape.
Thanks..


 
Posted : 04/06/2010 7:54 pm
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where's the "can o'worms" pic?


 
Posted : 04/06/2010 7:54 pm
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I think the idea is a lack of understanding about forces and torques.


 
Posted : 04/06/2010 7:57 pm
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Looks like a weird marketing exercise, they'll just be heavier and probably more flexi than straight cranks. Didn't they come out around the time of Biopace chainrings?


 
Posted : 04/06/2010 7:58 pm
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The idea behind them is to put them on the 'Bay and watch as retrofetishists spaff their load over them!


 
Posted : 04/06/2010 7:59 pm
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http://www.classicrendezvous.com/Italy/PMP_crk_ad.htm


 
Posted : 04/06/2010 8:00 pm
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German?


 
Posted : 04/06/2010 8:00 pm
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iirc the spiel was that they helped you over top dead centre, because downward pressure on the pedal would then apply torque to the shorter part of the L section.
Barking ๐Ÿ™‚


 
Posted : 04/06/2010 8:02 pm
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That spiel in the link is hilarious, did kaesae write it?


 
Posted : 04/06/2010 8:04 pm
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kenneththecurtain - Member
That spiel in the link is hilarious, did kaesae write it?

No, no mention of the BB or the grease in it!!


 
Posted : 04/06/2010 8:10 pm
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Wow! What utter, utter, utter twaddle !! (sez Rick)


 
Posted : 04/06/2010 8:11 pm
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Pedals for supporters of the Third Reich, whatever next.


 
Posted : 04/06/2010 8:18 pm
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Combine those with Biopace chainrings and.........


 
Posted : 04/06/2010 9:04 pm
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Correct me if I'm wrong but the leverage on those cranks is exactly the same as if you had a straight bar to the center. Given that you're pushing around an axle (the hub) it doesn't matter what shape your leaver takes.
Basically you draw a triangle from axle to pedal and the long side is your lever (the bit they've navigated around).
So, as far as I can tell that's just more weight and utterly useless?
Physics boffins please?


 
Posted : 04/06/2010 9:16 pm
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I'm no boffin, but 's exactly what I thought.

Based on that theory, I'm going to take my cranks off and remount them 20' further round on the crank. Should achieve the same result.

Ahem.


 
Posted : 04/06/2010 9:23 pm