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#21
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"Liquid Drive" bike prototype at auction
Tom Sherman wrote in message ...
Rick Onanian wrote: ... How about a bike shaped like a cow? That would be cool.... See http://www.chicagotraveler.com/cows/235.jpg Tom Sherman - Planet Earth Dear Tom, Thank you for a wonderful picture. My only regret is that it looks as if the handlebars are not the horns. Moo! Carl Fogel |
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#22
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"Liquid Drive" bike prototype at auction
A Muzi wrote in message ...
Carl Fogel wrote: -snip- Here's a stray question to emphasize the depth of my ignorance: are there fixed-gear tandems? If so, do they use a different gear--higher or lower--than either rider would normally use? -snip- Traditionally, the only competitive tandem event is on the track. Gearing used to be 46x16. (I haven't kept up with that.) Dear Andrew, I hope that you enjoy my naive questions as much as I enjoy your answers. Honest to God, they're racing fixed gear tandems around tracks? I love it. I have a vision of two tandems warily jockeying for position on a banked wooden oval, doing semi-trackstands and eyeing each other like gunfighters in a bad Western. I suppose that it's not like this really, but please don't spoil my fantasy. Thanks, Carl Fogel |
#23
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"Liquid Drive" bike prototype at auction
In article ,
(Chalo) wrote: It looks like the fella behind this CVT hydraulic bike is trying to raise some capital by selling off his prototype: http://cgi.ebay.com/ws/eBayISAPI.dll...tem=3641257316 http://www.powerengine.com It seems like a cool artifact, if not particularly practical. I know this particular bike has come up for discussion before, with a certain amount of pooh-poohing of the general concept. Since this thing surfaced again, I've been reflecting on what hypothetical advantages a hydraulically driven bike could have over a chain driven bike, which might offset the drawbacks of what is almost certainly a heavier, lossier, and more expensive system than chain drive. So far I've come up with: 1) True continuously variable transmission ratio, which this bike has Some people insist we want CVT, but hydraulically driven vehicles have always had it available and are still rather uncommon. For instance, Hondamatic motorcycles never caught on, though their system seemed to work as intended. I'm unconvinced that it's really as desirable as its proponents say. The original CB750A and CM450A Hondamatics were not CVTs. They used fluid torque converters instead of a plate clutch (just like any automatic car), and 2-speed transmissions. I'm not even sure if they had automatic shifting. http://100megsfree4.com/honda/h0700/amatic.htm You mean this Hondamatic? http://he.honda.ca/motorcycles/model...RX500FA_pf.asp It's not a motorcycle, but it is interesting. A hydraulic CVT on an ATV. I think the argument for a hydraulic CVT on a utility ATV is much stronger than the one for the same drivetrain on a motorcycle, and much, much stronger than the argument for a bike. How did CVT become associated with the HPV community, when human power seems to tolerate a wide range of RPM? It's a logical extension: like all underpowered engines, humans benefit from lots of gearing choices. This led people to believe that continuous gearing would be even better than a mere 18 or 27 or 30 speeds. 4) Possibly less regular maintenance and system wear Many hydraulically powered machines work around the clock for years between breakdowns in the hydraulic systems. (I am reminded of various forklifts I've worked with, whose batteries always seemed to be troublesome but whose hydraulics were seemingly invincible.) Hydraulic systems by their nature run in a lubricant bath, and much of the mechanical wear in them occurs to the fluid. I am sure that not every cyclist would be willing to give up a noticeable amount of efficiency to have a service interval measured in years, but some certainly would if the cost were not offensive. I think the problem is that you can get similar durability and better efficiency and weight by going to a shaft drive. That's why most performance-oriented applications (cars) use shafts as a compromise system when chain or gear drive setups don't have what it takes. The possibilities outrun my ability to imagine good uses for them-- so much about the bikes we know is just corollary to the chain drive, that it's difficult to imagine what a "normal" bike would be like in the absence of one. The high wheeler is what you get when you assume that a bike's cranks will drive its axle directly, and the diamond frame with derailleurs is what you get when you assume the use of a chain drive. If you don't assume either of those things, then what? I suppose the answer to that will have to await another feasible alternative, if there is one. Chalo Colina That's just the trick. Chain is so good, it defeats all other options. You use belts or enclosures if the filth bothers you, but that's it. Maybe some recumbents would benefit from a long, stiff shaft drive, given their ludicrous chain issues. -- Ryan Cousineau, http://www.sfu.ca/~rcousine President, Fabrizio Mazzoleni Fan Club |
#24
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"Liquid Drive" bike prototype at auction
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#25
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"Liquid Drive" bike prototype at auction
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#26
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"Liquid Drive" bike prototype at auction
Ryan Cousineau wrote in message ...
[massive snip] That's just the trick. Chain is so good, it defeats all other options. You use belts or enclosures if the filth bothers you, but that's it. Maybe some recumbents would benefit from a long, stiff shaft drive, given their ludicrous chain issues. Dear Ryan, I love ludicrous issues. I occasionally see recumbents wobbling along on my local bicycle path, but have never inspected a dead one's anatomy--possibly there is a secret recumbent graveyard. Is the length of the chain-run a problem? That is, are longer chains less efficient, harder to shift, more prone to wear? Or is it the peculiar arrangements rather than the mere length? Are recumbent chain problems worse than tandem chain problems? Any concrete answers or even wild speculation will be appreciated, since I'd hate to shoot such rare creatures just to dissect their chain anatomies. I can recall only a single tandem sighting in fifteen years and fear that they may be extinct in these parts. J.J. Audubon |
#27
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Recumbent bikes (was: "Liquid Drive" bike prototype at auction)
Carl Fogel wrote: Ryan Cousineau wrote in message ... [massive snip] That's just the trick. Chain is so good, it defeats all other options. You use belts or enclosures if the filth bothers you, but that's it. Maybe some recumbents would benefit from a long, stiff shaft drive, given their ludicrous chain issues. Dear Ryan, I love ludicrous issues. I occasionally see recumbents wobbling along on my local bicycle path, but have never inspected a dead one's anatomy--possibly there is a secret recumbent graveyard. Recumbent owners keep their bikes forever. There are no low quality/low price recumbents (equivalent to discount store bikes) and the majority of commercially produced recumbents were made in the last 10 years. Therefore, unlike upright bicycles, one is unlikely to find recumbents in dumpsters, along the curb, at police auctions of abandoned bikes, etc. Is the length of the chain-run a problem? That is, are longer chains less efficient, harder to shift, more prone to wear? Chain wear mainly occurs when the tension (power) side of the chain is bent around the drive cog(s). Since recumbent chains are generally much longer, they typically last much longer (assuming similar conditions of use). I suspect that the cost per unit distance for recumbent chains does not differ significantly from upright chains. Shifting quality on a recumbent depends primarily on the quality of derailleurs, shifters, cassettes and chainrings used. An advantage of RWD recumbents is that the chain angle is lessened when the driven cog does not line up with the driving chainring. One can get away with using cross-gears much more so than on an upright. On the downside, recumbent shifter cable runs are typically longer and more convoluted than those of uprights are, and this can impact shifting in a negative manner. Small drivewheel bicycles that use larger than normal chainrings generally have poorer shifting quality - this is true of both recumbents and small wheel uprights. I had 73/52 chainrings on a bike I used to own [1] and front shifting was not the best. This is compounded by the lack of large chainrings with ramps and pins. My current bike uses a clever step-up jackshaft to avoid this problem and has excellent from shifting. [2] Or is it the peculiar arrangements rather than the mere length? For reasons of aerodynamics (reduced frontal area) and power production (angle formed by the seatback, seat base and BB) unfaired performance recumbents have the BB located higher than the seat. A direct chain run from the BB to the rear sprocket(s) would pass through the rider. Therefore, some combination of mid-drive, jackshaft, chain idlers, chain tensioners and chain tubes is required for chain routing. Any concrete answers or even wild speculation will be appreciated, since I'd hate to shoot such rare creatures just to dissect their chain anatomies. I can recall only a single tandem sighting in fifteen years and fear that they may be extinct in these parts. J.J. Audubon [1] http://www.ihpva.org/incoming/2001/wbone2.jpg [2] http://www.ihpva.org/incoming/2002/sunset/Sunset001.jpg Tom Sherman - Planet Earth |
#28
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"Liquid Drive" bike prototype at auction
On Wed, 26 Nov 2003 23:35:44 -0600, Tom Sherman
wrote: Rick Onanian wrote: ... How about a bike shaped like a cow? That would be cool.... See http://www.chicagotraveler.com/cows/235.jpg That's a trike. Close enough...where can I get one? Tom Sherman - Planet Earth -- Rick "Moooooooo" Onanian |
#29
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"Liquid Drive" bike prototype at auction
Rick Onanian wrote: On Wed, 26 Nov 2003 23:35:44 -0600, Tom Sherman wrote: Rick Onanian wrote: ... How about a bike shaped like a cow? That would be cool.... See http://www.chicagotraveler.com/cows/235.jpg That's a trike. Close enough...where can I get one? Tom Sherman - Planet Earth -- Rick "Moooooooo" Onanian Unfortunately, all the cows were sold four years ago. http://www.chicagotraveler.com/cows_on_parade.htm Tom Sherman - Planet Earth |
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