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When pedaling a bicycle, the maximum torque occurs when the pedal stems are horizontal and the rider is pushing strait down. The least torque occurs when the pedal stems are vertical and the rider is pushing them forward or backward. To equalize the torque throughout the cycle, I suggest an elliptical
front sprocket with the pedal stems across the narrowest part of the sprocket. That way, the power ratio would be greatest when the pedals are horizontal and the at the highest torque. The power ratio would be lowest when the pedals are vertical and the torque is lowest. It would be like changing gears several times through the cycle.
Google
https://www.google....lliptical+chainring
Baked; WKTE; not shown to be useful AFAIK (in either orientation). [notexactly, Feb 14 2018]
Epitrochoids at a glance.
https://giphy.com/explore/epitrochoids
[2 fries shy of a happy meal, Feb 20 2018]
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Elliptical chainrings are already available, with the benefits claimed as you describe. Look up "osymetric chainring" for a particularly non-round design. |
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I have ridden a bike with one (for about five minutes), it feels very weird. |
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They are baked I'm afraid. Check out Shimano's "Biopace"
which appear on the occasional race bicycle. Strangely
though, they're not oriented to use the peak torque part of
the pedal stroke, but actually offset at a mysterious angle. I
heard psychopath and bicycle expert Lance Armstrong
explain that this is actually to optimize knee speed.
Apparently, the transition from the leg moving up to down is
very stressful and energy sapping. By manipulating the chain
ring they can mitigate peak acceleration at that point. |
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Admit it, [IT], you just like saying "epitrochoid", like you know what it means. |
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I'm trying to imagine anywhere where an epitrochoid could feasibly be
shoehorned into, and failing. |
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This could be because shoehorns are designed for shoes, by and
large. Are you sure you wouldn't be better off with an abstract-
mathematical-curve-horn? |
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No, the concrete is what you stand on. |
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What if you used a sort of outrigged cam to drive a shoehorn so that it tried to shoehorn your foot into a shoe while you were riding a bicycle? Might one end of that shoehorn then describe an epitrochoid while at it? |
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Cows have shoes ? We thought that was horses... |
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//just click on a camera icon and take a snap and
instantly post // |
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Oh. Well, if you think some form of instant-snap-talk
software would be anything other than an encouragement
for underemployed narcissists I suppose you could go for
it. |
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Perhaps the aggressive opposition to change cultured
'round these parts might convince the natives to
begrudgingly house the soon-to-be-destitute MS paint. It
would add functionality, but only a tiny amount, and
would contribute to less overall change. I for one, don't
want to live in a world without the living fossil of
graphics. |
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// an encouragement for underemployed narcissists // |
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[IT] would just adore that .... |
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// I for one, don't want to live in a world without the living fossil of graphics. // |
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Come, join us ... don't be afraid ... you'll wonder why you ever hesitated ... |
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And we give you a really neat head-mounted laser for dazzling non-Borg, absolutely free ... how cool is that ? |
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Geez, this was baked on my first rigid frame Costco (ahem, Price Club) mountain bike in 1988. |
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Now an elliptical gear that changed it's tooth number, in a compact form factor, would be on the want list. |
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Ooh, epitrochoid is a good word. |
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All Julia-Mandlebrot-ish and such. [link] |
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Circles outside of circles inside of circles around circles between circles through circles in a circle. |
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It's totally tubular to the max. |
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//Now an elliptical gear that changed it's tooth
number, in a compact form factor, would be on the
want list// |
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Maybe 3 chainrings stacked? Say 22-32-42 teeth.
35+50+70 grams or so for the stack? Well under
200g handling maybe 200lb/ft of torque? Shame it
already exists. I learned long ago that the bicycle is
about as perfect a machine as exists. It's simple
enough that anyone with engineering skills can enter
the market, there's enough enthusiasts for exotic
development and billions of people demanding them
for transport. They're almost perfect. Provided you
ignore all the frivolous
developments that took place after the Raleigh
Sports |
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No sorry, imagining a shapeshifting nanobot composite cog with torque sensing abilities that clicks like a swarm of bees. |
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// clicks like a swarm of bees. // |
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Software glitches do happen occasionally. Just don't reboot while riding. |
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//torque sensing abilities that clicks like a swarm of bees.// |
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I see I'm not the only one to have experience of the wonders
of mid 90's British engineering. The Hope TiGlide fulfilled
every facet of best practice in recent British engineering,
beautiful, expensive to buy, expensive to service with
irritating features. <link> |
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Odd link ... we thought it would be to the Typhoon .... |
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After all, you did say // every facet of best practice in recent British engineering, beautiful, expensive to buy, expensive to service with irritating features. // |
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Ehhhh shouldn’t this be gone by now, given that it’s totally
baked and widely known to already exist. I'm throwing this
bone at it begin the process. {-} |
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//Ehhhh shouldn’t this be gone by now, given that it’s
totally baked and// |
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Well, the ORIGINAL purpose of the idea has become
somewhat redundant. There's been a little mission creep
and in the absence of a common goal individuals have
very much switched to their own agendas. For political
purposes, we're all still very much committed to our goals
and would like to request additional funding to cover the
expenses that arise with the creation of a more inclusive
and diverse goal sphere. Many goals are so diverse as to
be diametrically opposed, as such tremendous resources
are needed to ensure balance. |
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My personal goals revolve around thinking up something
funny about the Eurofighter and the engineering thereof.
Once achieved, I'm happy to consider alternative motions
until the steering committee is convened regarding the
selection of AGM location (Tuscany) and Christmas party
booze budget. |
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// a more inclusive and diverse goal sphere. Many goals are so diverse as to be diametrically opposed, as such tremendous resources are needed to ensure balance. // |
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It's very unwise to make such a sweeping statement without first having a properly constituted Goal Diversity Diversity Review Working Party to examine and report on the issues. While the majority of the work can probably be office-based (suites at a five-star hotel and a conference room for the delegates would be adequate), obviously a fair amount of field work will unfortunately be required.
We understand that locations such as Monte Carlo, Antibes and the Sorrento area provide a suitable amount of cutural diversity during the winter months of the northern hemisphere; a great saving can therefore be achieved by chartering a moderately sized cruise liner for the use of the field team, being able to deliver both transport, working space and accomodation in one economical unit. |
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We suggest an advance inspection group is sent to Tuscany to inspect potential venues. A proper entertainment budget can't be determined until the exact parameters of the event itself have been defined. That will require the report of the beverage selection working party to be signed off ... which may take some time. |
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All that's needed is for [xen] to forward a Letter of Intent with regard to open-ended funding of the work. |
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