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Tandem Cycling A bicycle built for two. Want to find out more about this wonderful world of tandems? Check out this forum to talk with other tandem enthusiasts. Captains and stokers welcome!

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Old 06-22-04, 04:07 PM   #1
Gibber
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Tandem Tricycle Student Project - Need Advice

My name is Bryce Gibson and I am currently a junior at Wentworth Institute of Technology. I am researching everything and anything that has to do with bicycles and tricycles for a project. As of right now we are designing a tandem tricycle for urban use only. I am looking for any information or thoughts that you may have. More specifically, if anyone knows if a shaft drive system can be implemented on a tandem bike please reply. Thanks a lot.
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Old 06-22-04, 07:37 PM   #2
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Bryce:
Have only seen one bicycle with a shaft drive and have heard of a couple more.
Seems chains are more praticable and would be less pricey.
There are several trike designs out there and some are real industrial-type work bikes rather than for sport/fun.
There are some racing/sport tandem trike afficionados in Great Britain and a couple recumbent tandem trikes being built in the U.S. but cannot help with brand names except for Workmans Cycles.
Good luck with the project!
Rudy & Kay/Zonatandem
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Old 06-23-04, 05:24 AM   #3
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Quote:
Originally Posted by Gibber
My name is Bryce Gibson and I am currently a junior at Wentworth Institute of Technology. I am researching everything and anything that has to do with bicycles and tricycles for a project. As of right now we are designing a tandem tricycle for urban use only. I am looking for any information or thoughts that you may have. More specifically, if anyone knows if a shaft drive system can be implemented on a tandem bike please reply. Thanks a lot.

Bryce,

There are plenty of tricycles already in production, some tandems maybe also. None use a drive shaft. A drive shaft wastes to much power because of friction and 90 deg. changes in rotation. A chain drive is 98-99% efficient. This is why racing motorcycles all use a chain (with the exception of BMW which never wins anything).

Galen
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Old 06-24-04, 05:35 AM   #4
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Quote:
Originally Posted by Gibber
My name is Bryce Gibson and I am currently a junior at Wentworth Institute of Technology. I am researching everything and anything that has to do with bicycles and tricycles for a project. As of right now we are designing a tandem tricycle for urban use only. I am looking for any information or thoughts that you may have. More specifically, if anyone knows if a shaft drive system can be implemented on a tandem bike please reply. Thanks a lot.
If you're set on building a trike, put the two wheels in front. It allows you to benefit from all of the engineering that has gone into conventional bicycle drive lines, saves on having to figure out the differential thing for the rear, and the axle bearings for trikes with two rear wheels have a history of being maintenance problems.
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Old 06-24-04, 06:00 AM   #5
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I think used is a good way to go. Problem is, I have not seen any large/extra large/jumbo frames locally or on Ebay. I am 6'4" tall, so I need a biggie. Also, most of the stuff I have seen is so old the rear triangle would have to be re-set to 145mm spacing to run 9 speed. Older aluminum can't be reset...

Galen
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Old 06-24-04, 05:20 PM   #6
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I think we are planning on having the two wheels in front, it seems to make the most sense. Thanks a lot for your advice, I really appreciate it.
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Old 06-24-04, 05:23 PM   #7
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This is a great tip. We were pushing hard to use a shaft drive system but we may reconsider. We were under the impression that the extra cost and weight of a the drive shaft would be worth it considering their efficiency and durability. What do you know about trikes and steering capabilities. If we are planning on putting two wheels in front what are our options for steering. Do we use the two front wheels to steer or the back. If you have any more information I would appreciate it. Thanks alot.
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Old 06-24-04, 09:14 PM   #8
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Gibber, my man...

Think a bit before you head off on a tangent that will only end in failure. The bicycle in it's present form has been around for well over 100 years. Basic configuration: Chain drive with the steering in front. If shafts were "worth it," every bike you saw would have them. You never have seen one...ever, have you? Even if it was the cost that held the general public back, if shaft drive were in any way better, regardless of the cost, the elite racer's would use them. They don't.

Steering in the rear. Are you kidding?? Any idea what complications that throws into the mix?? Don't even think if that.

You sound a lot like a university mechanical engineering student in search of a "ground-breaking" project. Well, totally re-designing human-powered transportation is not a good place to start throwing in all kinds of wild ideas. Believe me, with the exception of new high-strength materials and what they allow, there is nothing new under the sun. It's all been done before. Done and failed. Full suspension--look in the late 1800's for that. Unusual frame configurations--even further back. There is a reason why bikes and trikes look and function like they do. They're simple, relatively cheap, and durable.

Now, if you could come up with some wrinkle that's "new" that's another matter. For example, how about a tricycle for a particular type of handicap? Stick with a "normal" trike and adapt it only where needed for the handicap. You might come up with something.

Have to use the "urban trike" theme?...Well, then change only that which makes an "urban" machine different from any other presently on the market (though I can't imagine what that might be, myself).

In short, take what works and tweak it. Any idea what the cost differential in a chain-drive vs. shaft would be? Huge. No way to market that to "urban" consumers.

Please...get a business student involved with your team. Remember, anything you invent has to be economically viable, not just "cool" technically.

I know this sounds harsh. Dude, do some research. That's what school is for. Believe me, I know. Back in the '80's I was a member of a similar project team (sounds like). Our focus was to produce a cheap, effective, and stylish fairing for the traditional drop-handled road bike. It was tough, but we pulled it off...trouble was, no-one wanted the thing, even though it was "cool" to beat the band.

Just a wake-up note...

Last edited by Eurastus; 06-25-04 at 06:04 AM.
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Old 09-05-04, 11:57 AM   #9
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Eurastus, you'd never work for me! You don't sound "harsh," you sound narrow-minded.

The education process is far more than creating "cool stuff." The creative process is too often handicapped by taking your attitude that all the creative stuff has already been done before. The creative process is also crippled by clouded or misplaced thinking (such as yours).

With regards to chain drive versus shaft drive. Motorcycles have traditionally used chains as they were the easiest and quickest way to design them at the start. As with many early innovations, they stick not because they are best, but because they are so well intrenched (e.g. the QWRTY keyboard versus more efficient designs). Motorcycles also get away with this as the chain isn't shifting position through a derailer to change gears. [NOTE: Knowing some of the BMW insiders, there is little corporate emphasis on Beemer racing versus Bimmer racing. If they wanted to, BMW could easily dominate the sport as they have in other areas of motorsports.] If chains were so good, why don't we use them on automobiles?

Gibber should obviously take into consideration some of the practicalities of finding the simplest design to accomplish what it is he wants to accomplish. Given your line of logic, A.G. Bell should never have bothered trying to develop the telephone (a view you actually shared with his father-in-law). Those foolish Wright brothers, what were they thinking? Or that other Wright (Frank L.), where did those stupid designs come from? Dyson, what a dope! 5,000+ prototypes to come up with a bagless vac (they are fantastic by the way) - vacuums have already advanced as far as they can go!

Gibber, as a designer, inventor, and student of human behavior, my advise is to ask a lot of questions. If it makes sense, use it. If it doesn't, determine if it is because you don't understand or simply disagree. Take small steps. If you succeed, take another. If you fail, small steps are easier to recover from. Chances are you will also learn more from your mistakes (assuming you are paying attention) than your successes.

If you haven't already discovered it, here is a link to a great direct drive system www.sussex.com.tw/se2.htm

Best of luck with your project. I'd be interested in learning how it comes out as I'm interested in a tandem tadpole myself.

Regards,
James
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Old 09-28-04, 09:51 PM   #10
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Speaking as one who has just built a tandem three wheeler (and I hope I can find
out how to show you a picture of it), if you really mean 'for urban use', the research
was done decades ago and the practical forms are the ones you see in parts of
the world where, when you pay for a lift on the street, the driver is also the motor.
By this, we mean single wheel out front, chain drive. Shaft drives only become
practical when the power available challenges the durability of a chain. That doesn't
much happen with two foot power. If you put two wheels out front you have to
put them both in forks or everyone who rides it must learn how to steer something
else than what they think of as a bicycle. The extra hardware isn't anything you
want to add to your total weight. The more you get involved in such a project,
the more you realize why most folks would just as soon use two bicycles. Our machine
was built to provide passenger space, rickshaw style. We 'stretched' a three wheeler
that originally had a basket over the rear axle, usual stuff. It was relatively simple
because we started with a rig that was already two pieces bolted together.
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Old 10-03-04, 12:04 AM   #11
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Quote:
Originally Posted by Gibber
My name is Bryce Gibson and I am currently a junior at Wentworth Institute of Technology. I am researching everything and anything that has to do with bicycles and tricycles for a project. As of right now we are designing a tandem tricycle for urban use only. I am looking for any information or thoughts that you may have. More specifically, if anyone knows if a shaft drive system can be implemented on a tandem bike please reply. Thanks a lot.

If looking at an upright tandom tadpole (two wheels in front), look at a Welsh Trike-Roman Wheels Netwon Trikes for some ideas:
http://www.ddol-las.fsnet.co.uk/romanroad.htm

Trailmate also makes side by side (sociable like Workman) deltas (one wheel in front).
www.trailmate.com

Heres some useful links:

http://webpages.charter.net/rcgilmore/Illustrations.htm



If going rear wheel drive, Id avoid the complications of steering and drive on that same rear wheel.

If side by side sociable rider arrangement, fwd with each rider independently driving his own wheels is practical, particularly on recumbent or semi-recumbent rider position

In a side by side delta arrangement you might also go to independent rwd-each driver cranking his own wheel-avoids differential issues and drivetrain complication-standard bicycle drivetrain.

Ive seen some longitudinal oriented shaft drive bikes on folders trying to avoid the mess of a chain-they are heavy 45 lbs for an Aluminum folder with the shaft drive and the internal gear hub.

Sidewinder is a rear steer fwd tadpole recumbent
http://www.sidewindercycle.com/

Culty and Stites and Raven (appears to have just been renamed tricumbent) are rear steer delta recumbents;
http://www.culty.de/
http://www.stitesdesign.com/wrap_hpv.html
http://www.justtwobikes.com/models_trike.html


See Eric Wannees rear steer trike page:
http://www.wannee.nl/hpv/abt/e-abd.htm
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