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wow thats awesome. but i was thinking mor elike the top tube plunged down to become the fork itself and then the bars adiated out off the fork legs in a nice curved or even 'swoopy' manner. beats me.
awesome post with the photos though. |
huh?
how would you turn? |
those off center fork things are wacky
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Originally Posted by Analog
Fixed-Gear coaster!
Sounds kind of like a sin, doesn't it? I was thinking: Fixed rear hub, freewheeling cranks that had a pin that you push in or pull out to either allow or disallow coasting. |
Originally Posted by skanking biker
Invent a bike with the geometry of a recumbent only flipped so the rider is forward facing with his legs behind him. In other words, a bike where you are prone (kinda like the characters in Tron) with the riders pelvis/stomach resting on some sort of padding device.
I've seen one. |
integrated top tube pad.
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[QUOTE=summerinside]Here are some photos to start the ideas flowin:
http://www.auburn.edu/ind/awards/hasty1.jpg [QUOTE] that is what i am talking about where do i get one of those? |
A heated seat for those long winter commutes
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In all practicalness, there is always new territory. Or at least a chance to try again where others have failed.
Something I've been pondering in my head over the past few days is a two-speed fixed gear drivetrain. I envision a bike with two chains, each with it's own cog and chainring. Possibly one chain on each side of the bike. Only one chain would be driven at a time, and either the hub or the crankset would have integrated provisions to allow the unused gearing to ride along disconnected from the system at one end. It would be like having a freewheel that either spins freely in both directions or can be locked up solidly by the rider. "Shifting" gears could possibly be accomplished by an indexed rod sliding through the bottom bracket that the rider could click back and forth with his heels to engage one ratio or the other. It would be somewhat heavy and probably very difficult to shift while in motion, but might be a great thing to have in a city like SF where there are plenty of hills to be had and no single gearing works well for everything. Even if it was manually engaged or disengaged by the rider while stopped, it would still be quite a bit faster and easier to change ratios than the traditional way using a flip-flop hub populated on both sides. |
Originally Posted by brunning
integrated top tube pad.
I'm already working on lugs that would work with leather/other upholstered tubing, make a sweet looking ride. |
integrated sparks fountain with no less than 4 jets and 6 terraces.
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Rig up an old wheel generator to deliver some juice to the seat whenever the bike is in motion. Helps break people who ride too much, give em that negative reinforcement/association. Or use it for sprint competitions
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I'd like to see a hub that would switch from fixed to free in seconds without taking the wheel off.
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http://linkpuncher.tripod.com/wwnbicy.jpg http://www.spaceworld2000.com/astrobik.jpg http://web.media.mit.edu/~tim/pix/20...2/img_1057.jpg
http://www.oldbicycle.co.uk/baines1.jpg http://www.tin-soldier.com/FATE1.JPG http://www.flyingfurniture.com.au/im...raft%20vk2.JPG http://www.ocregister.com/newsimages...ourth.bike.jpg |
Originally Posted by marqueemoon
I'd like to see a hub that would switch from fixed to free in seconds without taking the wheel off.
You can get a very similar effect by using a set of lock-out Power Cranks on a track bike..uber expensive though, I think the lock out version of power cranks run $1200.00 plus |
the www.bikeforest.com ought to get your nogin workin...
examples: http://www.bikeforest.com/unwheeldy.jpg http://www.bikeforest.com/vonbotbyl2.jpg http://www.bikeforest.com/killian_sidewaysbike.jpg this thing is cool... it's like engineless mass transit! imagine getting on a "bus" and sitting in a seat and everyone pedals together to get across town, that would be cool... though it would suck if you were on the late bus and it was just you and some old lady... http://www.bikeforest.com/ms_ride_big_bike.jpg also interesting... the "hula bike" the rear wheel is eccentrically laced, so you rock your body up and down to move it. http://www.bikeforest.com/hularental.jpg |
Yeah, I had checked out bikeforest my personal favorite is the treadmill-bike that they "tale off some sweet jumps."
All this is for my mechanical engineering design class. Cost isn't really important as long as the prof. thinks its cool. I thought about a couple different things, but there are some crazy good bicycle designers in Japan and China. Apparently they have design contests every friggin' weekend because there are a ridiculous amount of cool Chinese and Japanese designs. Here's an example: http://image.baidu.com/i?ct=50331648...E8%BC%C6&in=45 I'd thought about an expanding chainring design except you'd have to use a friction belt because you couldn't get a chain to engage the varying pitch between teeth. I'd also thought about the free/coast hub, but it would be dangerous to reengage the fixed nature of it while riding (I tried thinking of some way to slowly bring them up to speed, but I've got nothing). That example picture was something I thought of an then found it already designed. Someone mentioned a regenerative braking that would be used later to provide a boost, I thought about that as well, but didn't develop the concept much. Further ideas greatly appreciated, thanks everyone. Keep 'em coming. |
Originally Posted by Fix_me_up
I'd also thought about the free/coast hub, but it would be dangerous to reengage the fixed nature of it while riding (I tried thinking of some way to slowly bring them up to speed, but I've got nothing).
You would have trouble synchronizing the speed without breaking things if the non-fixed setting did not have a ratchet, but I also see no real point of having a system that is 100% free. You might as well build in a ratchet so that when the hub is not locked solidly (fixed), it would behave like a singlespeed bicycle that has the same gear ratio but coasts when the rider stops pedaling. I think this would be the most practical design. With a ratcheted freewheel, synchronization would be simple, but not idiot-proof. The rider would merely have to resume pedaling fast enough that the ratchet locks up, and then engage whatever mechanism locks the hub into a fixed. If you did for some reason want a design with no freewheel ratchet, you could also use some kind of indexed system that has an intermediate setting that clicks loudly as the cog and hub counterrotate to allow the rider to audibly synchronize their pedal speed before engaging the lockup mechanism the whole way. Just engage the lever halfway and change your pedal speed until the clicking sound slows to a stop and then lock the hub. I can't think of an easy way to prevent people from engaging the lockout while the speeds are badly out of sync, which could probably break an ankle if the rider accidentally (or out of stupidity) locked the hub on a fast descent with the pedals stopped. fixed/free design aside, I still vote for a simple multiple-speed fixed hub. Like an English 3 speed planetary hub, but one that doesn't freewheel and also has as little slop as possible. You can modify certian SA planetary 3-speed hubs to make a 2 speed fixed hub, but it is a bit spooky with regards to reliability and strength and there is an uncomfortable amount of rotational slop from the hub when transitioning from pedaling to resisting and back again. If you could design a strong and simple planetary (or other) gear setup that could be built into a hub and activated by the rider in some fashion to get multiple fixed gears with no wrenching and flipping of wheels, you could probably get rich off of it. Strength and reliability would be key though, since there are enough people in this world that would want to run it with no brake and expect it not to puke its guts at a bad time. |
Wow I am tired, I botched a bunch of stuff in that previous post from me. I meant to say I was really looking into the fixed/coast hub (so that you could pedal in both forms, but coast in one). I've got a basic idea of how it would work but I need to look further into the workings of current single freewheels and most importantly, I need find a way to stop someone from re-engaging the fixed nature without unless their cadence is matching that of what is needed to apply some force to the wheel.
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i would guess that it would be possible to build a singlespeed freewheel with some kind of lockout mechanism, functioning similarly to the ratcheting screwdriver i've got in front of me.
it's got a three position switch on the side. in the up position, the ratcheting mechanism can turn right. in the down position, it can turn left. in the center position, the ratchet is locked out ("fixed", if you will), and doesn't ratchet in either direction. |
I'd thought about an expanding chainring design except you'd have to use a friction belt because you couldn't get a chain to engage the varying pitch between teeth. How about a fixe with a planetery gear system in the bb/crank set. |
As for your safety mechanism: make the locking part use pins that slide from the hub body to engage the freewheel/cog and prevent it from turning separately from the hub.
Have a plate mounted to the hub that is able to rotate 5 or 10 degrees and is spring loaded to return to the counterclockwise-most position. This plate would have holes drilled in it to accomodate the pins of the locking mechanism, but they would only line up and allow the pins to pass through the plate when it was rotated to the clockwise position. Now make some kind of freewheeling cog with a proper ratchet. When the ratchet engages the hub to apply driving power to it, the ratchet actually catches against this rotating plate thing. When you pedal and apply force to the rear wheel (which guarantees a matched cadence), the plate is held in the clockwise position, which lines up the holes and allows the pins to pass through the plate and into the freewheeling cog to lock it up. Do I get extra credit? Maybe just beer? |
[QUOTE=wearyourtruth]
this thing is cool... it's like engineless mass transit! imagine getting on a "bus" and sitting in a seat and everyone pedals together to get across town, that would be cool... though it would suck if you were on the late bus and it was just you and some old lady... http://www.bikeforest.com/ms_ride_big_bike.jpg yeah---except that supposses everyone pedals with equal enthusiasm--how do you deal with the schmoo who decides to lollygag it and not pedal-----inherent problem with all commune ideals |
incorporate load cells into the pedals and build a circuit that compares the forces applied over time for all of the riders to see who is slacking. This should naturally be hooked up to electrodes mounted to the seats to automatically motivate the slackers...
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