New Cervelo R3 Road Bike
08-01-08, 06:28 PM
#51
just keep riding
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08-01-08, 06:41 PM
#52
gone ride'n
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Check this out and read the SRM technical discussion. SRM professional is the gold standard for power meters but $3500 for D/A is a lot of money for electronics. https://www.biketechreview.com/archive/pm_review.htm
Hopefully Mieke will provide how quarq does it.
Hopefully Mieke will provide how quarq does it.
08-01-08, 11:43 PM
#53
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Sorry - don't mean to be critical but as an engineer I don't see how this is possible. I agree you can sense the torque on the right side but can't see how you capture the left side. If I were to only pedal with my left foot what would your system read? Call me skeptical but I don't see how you can measure torque on the left side if your sensors are not between the left pedal and the chain. Please explain - I am all ears. Since I have never disassembled a bottom bracket maybe I do not understand the mechanical linkage - does the shaft to the left pedal connect to the chain rings through the spider?
The torque applied with both your left and right legs goes through your chainrings to propel your bike forward. In other words, if you were to just pedal with your left leg, you are still putting force through the chainrings and chain to propel the bike. The only thing bolted to the chainrings is your spider.That means the torque from both legs goes through the spider as well.
The left crank arm is bolted to the bottom bracket spindle that connects directly to the right crank arm/spider assembly. That's how we can measure the combined torque in the spider.
If that doesn't make sense, I'll have Jim, the Quarq founder / engineer explain it in more detail.
Mieke
08-02-08, 12:05 AM
#54
His Brain is Gone!
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I watched a bit of the cycling portion of the Madison official Ironman competition last summer. There were a lot of riders on Cervelo bikes.
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"Too often I would hear men boast of the miles covered that day, rarely of what they had seen." Louis L'Amour
There are two types of road bikers: bikers who are faster than me, and me. Bruce Cameron - Denver Post
08-02-08, 05:41 AM
#55
gone ride'n
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If thats the case I get it. If the left crank torques gets transferred through the spindle and into the right spider before it gets transferred to the chain ring then I see how it works. So I go back to my original comment - cool design. What I like about measuring at the crank (Spindle or spider) is that you are measuring closer to the engine than the Powertap. Thanks for clearing that up.
