SDV Drive!
A fellow on the steel is real FB page posted this thing!
With the video from Alan Duignan, found this info about the SDV system. Quite a few links in there as well to the actual company website and an employee from that bike company even commented on this blog post: https://tadpolerider2.wordpress.com/2015/10/12/sdv-drive-with-oval-pedal-motion-a-more-efficient-drive-system/ [img]blob:https://www.bikeforums.net/ff2c86d2-7e10-46fe-8c71-9245f408133b[/img] https://m.youtube.com/watch?v=EpiEX2...ature=youtu.be https://cimg8.ibsrv.net/gimg/bikefor...fbe49dcd7.jpeg |
More like WTF drive! All those moving levers remind me of Walschaerts valve gear on a steam locomotive. And my goodness, just watching that guy pedal makes my knees hurt. Looks like fast transitions top and bottom, sharply transitioning to a linear power stroke. Kind of an extreme oval ring, in the orientation that Chris Froome had them clocked, opposite of Biopace. But the feet aren't moving in circles, so the knee angle change would be less. Hm. :foo:
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Now we know the answer to the question: "How do I make my bike heavier, uglier, and more complicated with no discernible benefit?" :)
DD |
Originally Posted by Drillium Dude
(Post 21405608)
Now we know the answer to the question: "How do I make my bike heavier, uglier, and more complicated with no discernible benefit?" :)
DD |
There has to be a less complicated way to move the pedals a bit more towards the rear for time-trialling. The Q-factor on that looks astronomical too.
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Originally Posted by USAZorro
(Post 21405714)
There has to be a less complicated way to move the pedals a bit more towards the rear for time-trialling. The Q-factor on that looks astronomical too.
reminds me of a stair climber. |
Wouldn’t it be easier, to just hook up a few Husky-dawgs up front, & let them pull ya? 🙄😁😉 And what’s up with that headset? 🤔 This is apparently the end-result of hoarding, with too much free time & spare parts.
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Wow, I've got to get me one of those! If you read the original article on this system from 2002 (http://www.hupi.org/HPeJ/0013/sdv.pdf) they claimed to have measured something like a 20% power increase, something that would be quite useful in sprints...if you believe it. Also, the system would be so distracting to your competitors that you'd flash past them while they were gaping.
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Why?.......
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1. Just because you can doesn't mean you should.
2. Three chains, five chain wheels, two bottom brackets, six pivoting links, do not equal a paragon of mechanical efficiency regardless of how you pedal it. 3. "Fig.3 delivers 1.35 times lager output power than that by a conventional drive represented by Fig. 1". "The cadences for LMPs of the SDV drive vary from 20.8 rpm to 38 rpm as heart rate increases and those for the conventional one vary from 35.3 rpm to 88.9 rpm as heart rate increases". There is no free lunch as the above quotes show, SDV drive is a friction monster. : Mike |
Oh, man, I sooooo wanna ride that bike. Just once. Don't wanna own it.
I'd like to try a swing bike, too. And one of those set up with the steering to work backwards. But the one in this post I'm pretty sure I could ride without falling and hurting myself. :) |
Originally Posted by scarlson
(Post 21405690)
Thought the answer to that question was di2 :roflmao:
The real answer to that question is hydraulic disc brakes! |
Originally Posted by Nemosengineer
(Post 21406605)
"Fig.3 delivers 1.35 times lager output power than that by a conventional drive represented by Fig. 1
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This video is 18 years old. I guess they didn't make it into production. Small mercies.
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There looks to be enough chainrings and chains down there to grind your ankles to hamburger if you are not careful.....
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Has been replaced by the elliptical bike, in a way.
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Originally Posted by RiddleOfSteel
(Post 21406696)
The real answer to that question is hydraulic disc brakes!
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SDV, Uhhhhhh, new one to me, thanks for posting it!
I would love to ride 50 miles on it to really get a feel for it, but I'm sure that will never happen.
Originally Posted by tricky
(Post 21409141)
Hey now! Every mountain biker (and soon CX'er) out there would beg to differ. :-D
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Originally Posted by jackbombay
(Post 21409186)
SDV, Uhhhhhh, new one to me, thanks for posting it!
I would love to ride 50 miles on it to really get a feel for it, but I'm sure that will never happen. I'm plenty happy with rim brakes on many of my bikes, but hydro discs are the cats pajamas, there is no debating that. GEtting them bled properly can be a hassle, but once set up they need zero attention, and I feel I could slow the rotation of the earth with them if I decided to do so. |
Originally Posted by tricky
(Post 21409141)
Hey now! Every mountain biker (and soon CX'er) out there would beg to differ. :-D
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Originally Posted by RiddleOfSteel
(Post 21409369)
Ok ok ok, I will relent! Or rather, caveat or qualify my disc brake comment to road bikes (and anything close). MTBs look sick with discs, and have for a long time. And CX/gravel stuff looks just fine with them as well, largely because they were made from the outset to be that way (IMO). Road bikes being as svelte and light as they have been for so long--the discs encroach on that lithe, all-about-the-ride-quality nature. Again, IMO. :)
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Originally Posted by tricky
(Post 21409458)
I see where you're coming from! Something about the classic lines of a C&V road bike are so lovely and caliper brakes are part of that. As much of a disc advocate as I am, I don't see a need for them on a sunny day road bike. But don't get me started on electronic shifting. The only reason I ever would want to charge my bike is for e-assist on a bike I am using to replace a car. Turns out you and I have opposing views on electronic shifting and disc brakes and both of us have luddite streaks. ;)
I've always loved the Di2 brifter shape. It looks wicked and feels wonderful. :) |
I wish the video of the SDV drive was better, I want to see it move slowly so I can see how power gets from the pedals to the drivetrain.
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That video is horrible. It is like just watching someone rev up a car engine to check out a new carburetor. Is there an actual demonstration video somewhere?
It looks needlessly complicated. |
Originally Posted by davester
(Post 21405953)
Wow, I've got to get me one of those! If you read the original article on this system from 2002 (http://www.hupi.org/HPeJ/0013/sdv.pdf) they claimed to have measured something like a 20% power increase, something that would be quite useful in sprints...if you believe it. Also, the system would be so distracting to your competitors that you'd flash past them while they were gaping.
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