A tandem bike is a great way for two cyclists to travel together -- they can converse easily, and they go at the same speed, even if one is pedaling harder. But what about people with solo bikes who want to experience the joys of tandeming?
The solution is the bike coupler; it turns two separate bikes into a three-wheeled tandem, or bike train. You simply take the front wheel off the back bike and use the coupler to connect the front fork of the back bike to the back fork of the front bike.
For larger groups of people, you can string together any number of bikes. Bike trains made up of 5, 10, even 100 bikes are possible, and sure to be noticed as the snake gracefully around town.-- AO, Jul 30 2003 Close (but not nearly as cool) http://www.sandsmachine.com/a_rod_t2.htm [Worldgineer, Oct 04 2004, last modified Oct 05 2004] Direct link and trailing link http://bz.pair.com/fun/traincycle.gif[14kb image] [bristolz, Oct 04 2004, last modified Oct 05 2004] Peloton. A word invented by someone French. http://www.sheldonb...loss_p.html#pelotonSo we don't have to call it a "bunch of bicyclists" anymore. [Amos Kito, Oct 04 2004, last modified Oct 05 2004] for kids http://www.fahrrads...o.at/trailgator.htm [squeak, Oct 04 2004, last modified Oct 05 2004] Bike Chain http://www.tandembar.com/guinesre.htmlWith 65 lucky participants. [Amos Kito, Oct 04 2004, last modified Oct 05 2004] Half-baked... http://angel.nomuta....uk/multicycle.html...by the Dutch Army [angel, Oct 04 2004, last modified Oct 05 2004] decent idea, I bet the crashes would be spectacular.-- SystemAdmin, Jul 30 2003 Such a simple, elegant idea must be baked... but I can't find it.-- Worldgineer, Jul 30 2003 Close, but I think you may not have thought this through quite far enough.
NumWheels = NumBikes + 1
So two bikes gives you three wheels. How does a three-wheeled bike (trike?) turn?
How would a 101-wheeled bike turn?
Unless of course you intend to only go in a straight line, then it's brilliant.-- DeathNinja, Jul 30 2003 Can't you just add a bit of a flexible coupling to the adapter? This would allow you to turn just fine.
(thinks for a moment) Wait. It's got that built in - the handlebar will swivel in relation to the bike. When a turn is made you'd still trace out a curve, causing the bike to turn. A 101-wheeled bike would turn in a long arch.-- Worldgineer, Jul 30 2003 The other 100 wheels aren't going to turn, and you can't pivot on multiple wheels. The only reason a 2-wheeled bike works is because it can pivot on the rear wheel when you turn the front wheel. The only way this would work is if you got the middle wheels to not touch the ground during the turn. This might work for 3 wheels, but at some point the leverage from the length of the train will hold the middle down anyway...-- DeathNinja, Jul 30 2003 Worldg is right, the swivelyness of the front fork and handlebars allows the train to bend at each coupling, in the same way that a regular train bends between the cars when it goes around a curve. The coupling would also have to allow for up-down bending for going over hills, so the bike train would be like a flexible chain of bikes.-- AO, Jul 30 2003 I agree with World and AO. They would flow like a snake. On the other hand, balance would be very difficult for the followers who lack independent steering for balance.-- FarmerJohn, Jul 30 2003 I think even that wouldn't be a big problem. Unless the snake's in nearly a straight line it won't tip over.-- Worldgineer, Jul 30 2003 The coupling doesn’t allow twisting, so you won’t fall over unless the people in front of and behind you also fall over, hence the spectacular crashes mentioned by SystemAdmin.-- AO, Jul 30 2003 DeathNinja, picture this with just two bikes for a second. When the front bike turns, the second attached bike's handlebar and front forks will turn with the back tire of the first bike. And so on and so on down the line.
I'd love to see this in action.-- waugsqueke, Jul 30 2003 The term "tandem bike" is a bit misleading in this case. I think if you draw it out on paper you'll see some of the problems with this design. I don't think it would work too well to attach the rear-bike's front fork to the front-bike's rear fork because that middle wheel will get in the way of the rear bike turning, even with a rubber coupling. Those forks are not very wide. I think you would need to set this up more as a train, where the rear bike attaches not to the rear fork of the front bike, but to a separate coupling even more rearward than the wheel, just like a real train. This lets the rear bike swing side-to-side without the middle wheel getting in the way. And if you do it this way, you don't even need to remove the front wheel of the rear bike.
Here is a diagram:
not like this: O--O--O
but like this: O--O.O--O
So this is like a train, not a tandem bike because power is not transmitted by each rider. Each rider simply powers his own bicycle and they are just all connected like a train...-- DeathNinja, Jul 30 2003 //the rear bike attaches ... to a separate coupling even more rearward than the wheel, just like a real train//
This should be an option, if only for the last bike in the train, so more bikes can couple into the train, during the trip. The rear wheel would have special grip knobs extending from the axle. A bike equipped with a "grabber fork" clamps onto that rear axle. Another bike can attach behind this one at any time. Any portion of the attached groups can release (mechanical lever) and go their separate ways. The gap can then be closed -- and ride on.-- Amos Kito, Jul 30 2003 Stopping might be tricky.-- waugsqueke, Jul 30 2003 Well, it wouldn't stop on a dime.-- FarmerJohn, Jul 31 2003 Damn I thought this was going to be more dynamic. When cycling up slight inclines on my journey to work I am often passed by individuals who are moderatley fitter than myself and I am often tempted to latch on for a free ride up the hill. I could have a little break and they, I'm sure, would enjoy the challange of the extra wieght. Perhaps a small grappling iron ....-- nichpo, Jul 31 2003 Nice idea. I can see this causing havoc trying to weave through rush hour traffic. It would be great fun! Nice sketch [bris], but that seat looks painful.-- silverstormer, Jul 31 2003 I've kinda sortof seen these for kids. Either the whole kid bike attaches to the back of an adult bike or there are ones where you take the front wheel off the baby bike and hitch what's left to the mummy bike.-- squeak, Jul 31 2003 //it wouldn't stop on a dime// Nonsense. It would stop a bit faster than a single bike could stop using one brake. This is assuming everyone hits their brake at the same time. Specifically (assuming the original configuration), the braking power can be described by the following equation:
braking power = (1/2 single bike braking power) x (number of bikes + 1)
whereas the mass of vehicle + riders to stop is only:
mov+rts = (mass of one vehicle + rider - front tire + linkage) x (number of riders) + front tire - linkage
(sorry, just in a useless equation mood)
[DeathNinja] I think your solution complicates this simple design. There is nothing wrong with a linkage between the front forks and the back forks (please see [bz]'s drawing). Please describe the problems involved further if you still disagree.-- Worldgineer, Jul 31 2003 Ah, but the trouble would be getting everyone to pull their brakes. The only person with good visibility is the rider at the front, so they are the one that is likely to brake first. They can't brake hard, otherwise the train will jackknife so, without linked brakes or another communication system (e.g. the leader shouting 'BRAKE!!!'), the train will take an age to come to an unplanned halt.
I like the idea of creating a coupling that goes from the rear axle of one bike to the front axle of the next (not one of bristolz's drawings). That keeps each bike intact and introduces as much flexibility as you want between the bikes. It would also keep the load per wheel at the designed value for the bike.-- st3f, Jul 31 2003 I was envisioning the "BRAKE!" method.-- Worldgineer, Jul 31 2003 [Amos] Great find. Though I like the front axle coupling better - it's more stable and would feel more like a tandem (because you're close to the other person).
[bp] //adapter plates welded// I was thinking of two small devices that each clamp onto a front fork arm and a rear fork arm.//braking// I like the "BRAKE!" method for it's simplicity and braking power.-- Worldgineer, Jul 31 2003 [World] // //it wouldn't stop on a dime// Nonsense.// I was jesting with the phrase's literal meaning.//"BRAKE!" method// Calculate in the speed of sound.-- FarmerJohn, Jul 31 2003 See link, taken from "Patent Applied For" by Fred Coppersmith and J. J. Lynx, published 1949. (There's a lot more where that came from.)-- angel, Jul 31 2003 [FJ] Sorry, should be spelled noncents. Oh, and I would guess someone would have to relay the "BRAKE!" yell every 100 bikers or so, slowing things down further (or failing to).-- Worldgineer, Jul 31 2003 I think if you actually got two bikes and tried this you would see the problem with the fork-to-fork linkage. When the middle wheel turns, the fork will collide with the wheel. You could only turn like maybe 5 degrees before the fork tries to go through the wheel... (or actually, the wheel tries to turn through the fork)-- DeathNinja, Jul 31 2003 Tour de France Team event. +1-- po, Jul 31 2003 [DN] Silly, the fork turns with the wheel. Exactly the same setup as with a normal front wheel.-- Worldgineer, Jul 31 2003 random, halfbakery