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American Legion Rider
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Discussion Starter · #1 ·
I see a trend to these upside down forks and question, why? There's a claim that they provide better rigidity but how can that be with the biggest thickest part on conventional forks being lower where twisting starts. I guess upside down you can add more bracing, but is that what it's all about or is it just a claimed appearance improvement? I really don't get it. It looks odd to me but I'm seeing more and more of this style.
 

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I've wondered that as well but was never that motivated to look it up. You motivated me! Here is an explanation that seems straightforward enough - http://tinyurl.com/y5j5a4hl
 

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The theory is that the inverted forks are more rigid and therefore improve handling. This has been professionally tested and for the most part proven to be untrue much like adding a fork brace it seems logical yet provides no measurable advantage.
 

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The rest of the theory, as the article at the link says, is that unsprung weight is reduced, resulting in better damping and control. Looking at photos of inverted forks, I wonder if there is really that much difference in moving mass. I've read that 1 ounce of usprung weight equals 7 ounces above the springs for damping control, so a little weight loss could help, I guess.
 

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A study of a horses lower leg will reveal the answer. Less un-sprung weight.
Einstein said it requires energy to move mass, and the amount of energy is in proportion to the mass. If the lower forks weigh more, they require more energy, to move them up and down. Energy in action creates heat. If you want very fine control over the movement, less weight helps. Move your mouse. Move your full coffee mug. Einstein is right again.

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The rest of the theory, as the article at the link says, is that unsprung weight is reduced, resulting in better damping and control. Looking at photos of inverted forks, I wonder if there is really that much difference in moving mass. I've read that 1 ounce of usprung weight equals 7 ounces above the springs for damping control, so a little weight loss could help, I guess.
You managed to just get that in before me.
For street riding I do not think it is necessary. Bluzu has normal forks and are more than good enough for the street. I think for very quick track riding, at the top of the leader board, there will be enough difference.

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American Legion Rider
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Discussion Starter · #7 ·
The rest of the theory, as the article at the link says, is that unsprung weight is reduced, resulting in better damping and control. Looking at photos of inverted forks, I wonder if there is really that much difference in moving mass. I've read that 1 ounce of usprung weight equals 7 ounces above the springs for damping control, so a little weight loss could help, I guess.
Well I would think if anything, the heavier tops now being on the bottom would cause slightly more resistance on dampening but could you even measure it? Like a heavier weight oil. I doubt it. But that might be the only benefit I can see with reversed fork tubes. I personally think people just bought into a fashion craze.
 

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Well I would think if anything, the heavier tops now being on the bottom would cause slightly more resistance on dampening but could you even measure it? Like a heavier weight oil. I doubt it. But that might be the only benefit I can see with reversed fork tubes. I personally think people just bought into a fashion craze.
Yes, kind of like holes in brake rotors to improve braking, or extra-wide tires on street bikes (for unknown reasons). I'd have to see measurements of similar inverted vs. normal forks to trust that there is really less moving mass.
 
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