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    MIT's e-bike

    Well making batteries more affordable would be the ideal spot to put it. Electric motors are old technology. They've existed for as long as we have had electricity, in fact the dynos used to generate electricity could also be used to create motors. So there is about as much to know about them...
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    MIT's e-bike

    Looks can be deceiving. It could be that the guy figured out some manufacturing process that would allow him to make such seemingly complex frame design done on the cheap or some other thing like that. I mean if the frame was just one big stamped item that could be turned out for 40 bucks a...
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    registered the dual etek bike trike as a moped

    I always figured that if the motor was off on a moped then it's not motorized anymore. Depending on the jurisdiction it's probably not actually necessary to register the moped at all. In my state, for example, I don't have to register or insure it or anything like that. I can legally drive it...
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    2-speed systems (R-D, dog-clutch or derailleur changing)

    I would not get to hung up about efficiency at the rear wheel like that. Efficiency is very nice at the motor because any wasted energy ends up as heat, which is bad, and puts heavier loads on the batteries. On a upright bicycle once you get over a certain speed inefficiencies in aerodynamics...
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    converting a dirt bike and making it street legal possible?

    Well that's what a moped is. It's just a bicycle with a motor. It differs from state to state, but in mine (which I think is typical) is that: 1. It MUST have working pedals. A moped is a moped because it has pedals. If it doesn't it's a scooter. This is a legal definition for moped and if...
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    2-speed systems (R-D, dog-clutch or derailleur changing)

    Wikipedia to the rescue: http://en.wikipedia.org/wiki/Sprag Or maybe not. The sprag patent from 1950's... http://www.google.com/patents?id=PKRIAAAAEBAJ&dq=2777551 Basically you have a bunch of little bars in the clutch that if you rotate it one direction they slide freely, but if you rotate...
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    2-speed systems (R-D, dog-clutch or derailleur changing)

    As long as your controller can handle the surge then it should be fine. Devices at my work will use reverse polarity as a braking mechanism for brushed motors. I'd probably check out controllers designed for robot combat as they are designed to take high loads, be abused, and whatnot and would...
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    converting a dirt bike and making it street legal possible?

    Depends on the state, of course. I don't know about Oregon. I know that in the midwest it's going to be much easier because we are able to avoid the whole environmental nazi brigade so far, but it's not looking that good. And on the west coast I expect that they have such little trust in their...
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    Spur gear retro-direct

    This is a very cool idea and I think it's actually very do-able... If you take the simpliest design, how much do you suppose would it cost to build? Hundred dollars in machine shop, 30-40 bucks for the backstop/sprag bearings, 50 dollars for the big spur gears, 20 dollars average cost for the...
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    Spur gear retro-direct

    Ya. I made my version just trying to figure out your concept. So it's definitely a variation on your idea. :)
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    Spur gear retro-direct

    Here is my rendition... background: (I know that everybody knows this and I know that you are not stupid, but I am just saying it for the sake of clarification and the description. Just so that everybody knows were I am coming from.) You know how when you spin you pedals in the wrong direction...
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    Spur gear retro-direct

    Do they make spur gears (or whatever) with one-way clutches like they do with freewheels? I think the technical term is 'sprauge clutch'. Because if so then the design should be relatively simple... You have have two sets of gears, one with a even number of gears so the output shaft rotates in...
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    Spur gear retro-direct

    Ya. I think your essentially aiming for: low gear going backwards and then high gear going forwards. (or visa versa). Is that right? Bicycles in the 1920's or so were able to do this using a single chain and two freewheels on the rear wheel. Some people have modern versions for the novelty...
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    Planetary + Clutch Dual Speed

    Well if your going to go with the dewalt hammerdrill route then the already come with a very nice all-metal gear reduction in them. On the low gear the output shaft runs 0-400 RPM which is about perfect for a bike. If you take the drill apart you can shove in spacers to force it always to be in...
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    Giant Yukon build

    At that point it doesn't really matter. A bicycle, or motorcycle, is about the most un-aerodynamic vehicles you could possibly imagine using. The energy losses of a chain tensioner amounts to you spitting in a monsoon of inefficiency. :) It's a very cool bike, btw.
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    The patent system

    Ya. The first thing we do, lets kill all the lawyers. -- Shakespeare :) Well ya, but that's the problem. If your violating a patent you don't need to be notified or know that your doing it. Your already breaking the law. Nobody is required to notify you about anything, that's just how the...
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    The patent system

    *shrug*. I am more aware of the issues involving patents and software. Which is much worse then anything else involving the patent system, and I won't go into it immediately. The patent system, like any form of artificial law can be twisted into doing things that is not intended. Another...
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    The patent system

    Hrm. Wrong forum, I think? That won't work. The mechanics of the patent system is so that you are given a temporary monopoly over a practical application of a idea or concept. Using this patent you can protect your own product or extract licensing fees from other people. There is no natural...
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    Planetary + Clutch Dual Speed

    I found a detailed example of a automatic 2-speed transmission for a scooter. http://scooter.wikia.com/wiki/Evo_two_speed_transmission It uses centrifugal clutch mechanism to switch between two belted gears. Pretty snazzy.
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    Phaser transmission (Is it as easy and good as it looks?)

    If you want 3 speeds then planetary is the way to go. It's a very strong, very compact design. See: http://science.howstuffworks.com/gear7.htm That's the sort of thing that is used in those 3-speed hubs and is used it automobile automatic transmissions. I would think that it's possible to...
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    Planetary + Clutch Dual Speed

    Compared to a derailer then ya the V-belt thing is VERY inefficient. In larger vehicles it's better and with CVT cars that use that type of drive train tend to get in between the efficiencies of manual transmission and automatic transmission. The advantage is that you can design the motor to...
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    High power RC motor and drive unit production

    It's about as nice as you can get. Very freaking cool. I look forward to obtaining one. One thing that you can do to possibly improve the device is add a rubber coupler from the gear to the motor. Electric motors tend to be rather jerky and while I know that this can be controlled by the...
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    Planetary + Clutch Dual Speed

    I have had two mopeds. My old one I got in highschool was a Honda thing.. it actually featured a CVT. It was the common belt-type were one pulley was split in half and got squeezed together, thus changing the diameter of the pully and thus the gearing. The one I currently have is a Puch with a...
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    Go cheap, or wildly exotic?

    Personally I want a nice quality steel bike, that I know will last. Next after the bike comes the batteries. The batteries are, IMO, the most critical thing about a build, related to performance, and are probably going to be the most expensive. People have been making all sorts of electric...
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    LiPoly powered 18HP Twin Motor Brushless MONSTER build!

    IMO you should really be aiming at a small motorcycle setup. The power and weight your aiming for far exceeds any sort of off-the-shelf mountain bike and is way past the legal limits for even mopeds. The bicycle chain, for example, is something that simply won't stand up to these power levels...
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