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PostPosted: Mon May 09, 2005 4:58 am 
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Joined: Sun Apr 11, 2004 5:21 pm
Posts: 101
Location: U.S.
The "virtual" crankarm length becomes longer at the top of the stroke (and shorter at the bottom) with greater stack height.

I believe the foot still travels around in exactly the same circle regardless of stack height... but the circle your foot travels is offset from the true crankarm circle by the stack height.


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PostPosted: Mon May 09, 2005 5:40 am 
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Joined: Thu Apr 07, 2005 4:30 am
Posts: 32
Location: Fort Bragg California
Halfway on the down stroke and halfway on the upstroke you are along side the crank arm . On the top of the stroke and bottom of the stroke you are on top of the crank arm and then located between the end of the crank arm and the bottom bracket on the bottom of the down stroke . so rather than a complete circle there is an eliptical motion . I have to constantly remind myself after I start to get fatigued to watch myself from starting to do a bio pace rythm . Where my I can hear my tires accelerating and slowing with each stroke . I think this pedal might just be a new break through in inovation for avid cyclists. I did 41 miles on my 30 lb Foes Fxr mountain bike today and I could have used everybit of help.


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Posted: Mon May 09, 2005 5:40 am 


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PostPosted: Mon May 09, 2005 7:20 am 
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Actually now that I think about it, it's impossible to know the exact path someone's foot is describing because not only does the stack height effect it... the amount that the foot is "toe down" or "heel down" changes it as well. It's a function of both of those.

Of course with the pedal that's the topic of this thread (zero stack height), it doesn't matter if the foot is toe down or heel down -- the foot (at least the spot in the foot that the imaginary spindle center passes through) goes around in a perfect circle.


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PostPosted: Mon May 09, 2005 3:24 pm 
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Location: Oxford - UK
Just from viewing the pedal, I'm concerned about the Q-Factor effect.

They appear to puch your shoes outwards and away from the crank arm more than "standard" clipless pedals.

anyone any info?

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PostPosted: Mon May 09, 2005 3:47 pm 
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Joined: Wed Nov 10, 2004 4:39 pm
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Location: Des Moines, IA
fdegrove wrote:
Sorry folks but you're dead wrong.
I didn't say the cranklength changed, I said that the "effective" cranklength changed. Not quite the same thing.


Ok, at the top your effective is a longer crank, on the bottom your effective is a shorter crank and on the right and left you have the same length crank.

You could have the slightest amount of vertical elliptical shape if you had a crazy tall pair of shoes and were a dramatic ankler. 1mm may be.

I don't think this would slow you down though, you would have less power at the top and bottom then you would at the down stroke, so you could have a better. Like those elliptical rings that Bobby Julich is using.


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PostPosted: Mon May 09, 2005 4:20 pm 
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Joined: Mon Apr 25, 2005 9:16 pm
Posts: 216
You're right about the Q-factor. It will be greater by quite a bit. That alone might inhibit some from liking this pedal. I think Q-factor is a personal preference like saddles... depends on body proportions. The absence of rocking torque and full circle pedalling is how they arrived at 3-4% gain. He didn't measure this himself but sent it out for testing. Anyways its funny how we're so market driven these days. All you need is Armstrong using these in the time trial or some pro team using them and bam....they'll be a huge hit like speedplays and cervelo bikes a la CSC.

I for one am waiting for the intial batches to move through and get reviewed and "tweaked".


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PostPosted: Mon May 09, 2005 4:30 pm 
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Joined: Tue Feb 15, 2005 1:33 pm
Posts: 200
Hi all.....

Just came from the hyperbookshop I frequent and did a quick flip through them pages looking for the weblink. So here it is-

http://www.sidemountpedal.com

Hope this works cuz I'm gonna view it after I just posted the link here..... :oops: :D


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 Post subject:
PostPosted: Mon May 09, 2005 8:20 pm 
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Joined: Tue May 03, 2005 2:20 am
Posts: 5773
Location: Belgium
Hi,

Quote:
I don't think this would slow you down though, you would have less power at the top and bottom then you would at the down stroke, so you could have a better. Like those elliptical rings that Bobby Julich is using.


Not bad but not quite there yet.....
Let's forget the crankarm for a minute and focus on the leg of the rider; due to increased stackheight his lower leg has seen an increase in length by about an inch with respect to the distance sole/center of pedal axis.

This means that the femur muscle now has to stretch further.
The pivotal points have been shifted noticeably: ankle to knee is still the same but the ankle is now at stackheight distance from the pivotal point of the pedal.
As we can see the stackheigt introduces a shift in the lever/pivot series that inevitably introduces a loss in energy transfer.

While you can train yourself to ride that it certainly isn't the most efficient.
Worst case scenario: you'll be shifting up one gear to be able to spin the crankarm system around.
Anyone who knows the ratios of gearing systems knows this isn't the right way to gain effeciency while pedaling as the same amount of energy now goes to a lower gear.

Ciao, :wink:

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