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Kobber
04-04-2010, 08:41 AM
Hi everyone,

Happy Easter!

So I'm thinking about transmission for my trike tandem. I'm toying with the idea of dual unified transmission, where each rider can pedal independently, but where the driving force from each crankset is transferred to both rear wheels through an intermediary axle,

A picture says a thousand words, so here's the basic idea:

http://lh3.ggpht.com/_1rYxS4qsQBg/S7iG4TsR0CI/AAAAAAAAAp4/fMYSGMmRjjQ/Unified%20transmission.jpg

Drawbacks
Heavier, more expensive, more complex, ...

Advantages
Neat idea, stability, ...

Anyone ever tried this? Any thoughts would be very welcome. The idea seems a bit silly to me from certain angles, but neat from others.

Take it easy, everyone!

Radical Brad
04-04-2010, 06:57 PM
Drop the 4 single speed freewheels (they are not needed) and you will have the drive system from The Kyoto Cruiser...

http://atomiczombie.com/product/kyoto/large1.jpg

Brad

Kobber
04-05-2010, 05:10 PM
Hi Brad,

There's this weird French cartoon series from the '70s called the Shadoks, and one of their favourite sayings is "Why make it simple when you can make it complicated?"

I feel like that with this idea. I don't need the four single speed cogs, the idea is to have drive going to both wheels, regardless of how many people are pedalling.

Stupid idea for a tandem, I guess, 'cause I'm not likely to take it out on my own ... call it a mental exercise. Thanks, and I'll use your advice to keep it simple, but more along the lines of the LodeRunner2, I think. I love that crossover ...

Shadoks:
http://eppee.ouvaton.org/IMG/jpg/shadoks-2.jpg
(for those interested, some translations below)

"If there is no solution, it's because there's no problem."
"The most serious of brain diseases is thinking."
"Why make it simple when you can make it complicated?"
"By continually trying, one finally succeeds. Therefore, the more you fail, the greater are your chances of succeeding."
"The concept of 'sieve' is not related to that of 'hole'."
"It is better to use one's power of intelligence for stupid matters than to use one's power of stupidity for intelligent matters."

And advice for anyone in a leadership position:

"To have the fewest possible disontented people, always beat on the same ones."

Radical Brad
04-05-2010, 08:52 PM
Great quotes! This one is also one of my favs...

Spock: Once you have eliminated the impossible, whatever remains, however improbable, must be the truth.

Brad

jimFPU
04-06-2010, 08:15 AM
'...a man's got to know his limitations...'-Spock. Usually followed by: 'I'm only one man.'-JimFPU

vrooom3440
04-06-2010, 10:23 AM
The problem with using freewheels for the differential is they put all the power to the wrong/inside wheel in a turn.

I have pondered scaling up a ball differential as used in RC cars.