Timmy Green, my homebuilt Delta Recumbent Trike.

Step 6 Only 1 Front Derailer

Only 1 Front Derailer is used for gear shifting on the front triple Chain ring with standard 24,36 & 44 teeth driving a standard 18 teeth Freewheel cog. A Rear Derailer is used midway to act as a Chain Tensioner. 
The Rear Axle is linked to the left Rear Wheel through a 1:1 Final Drive set up using 2 standard 18T Freewheel cogs. 
Another 18 teeth Freewheel is used on the Rear drive wheel. No Derailer is fitted to ease tire removal during puncture.
Rear brake is only on the Right rear wheel to evenise wear & tear of driving & stopping on opposite tires.

Comments

[alexwelton]

how long did it take to make your homebuilt delta recumbent trike?

[Timothy Wooi]

I took me about 2 weeks from design to spray paint.

[alexwelton]

its amazing

[dwrenne]

Nice job. Using a front derailer is a sweet innovation and using the rear derailer just for tensioning is clever. Any reasons why you didn't decide to drive both rear wheels.

[The Wapusk]

The issue with supplying power to both rear wheels is there is no easy/inexpensive  way to construct a differential.  Without which both wheels would move at the same speed as each other reguardless of what was required of them.  When cornering the outside wheel would need to spin faster then the inside wheel, as it travels a larger diameter curve, and would scrub on the ground acting as a passive brake.

[tarala]

very good instuctable... and wapusk, now i know what the diff in the car does... i am going to tell everyone! 

[Timothy Wooi]

When you go to a hobbyist shop , just take a look at a moderately high end scale model of a remote control  buggy or 4WD .Spin the right rear wheel clockwise and look at the rotation of left rear wheel.
It spins counterclockwise when theres no load applied.
A differential will automatically engage to spin faster when the opposite side experience a heavier load/traction thus improve handling at corners!

[static]

 There is a simple inexpensive way to drive two wheels that lets the wheel with the least traction, freewheel while slightly in a turn turning. A ratcheting drive cog is employed at each wheel

[Timothy Wooi]

Tks for the englightenment to why only 1 drive is used.
Unless you want to incoperate put 2 freewheel at the 2 rear wheels,you can dive 2 wheels at the same time compensate for the turning effect like that of a differential gear assembly without wearing much of the tires!
Tim

[Timothy Wooi]

Hi Dwrenne,
You can use to drive 2 wheels but needs more parts to build/fabricate. You will have slightly more pedalling resistance but get better traction in contra. 

As our average human power is only about 1/8hp! and to why I use only 1 wheel to drive is to reduce frictional & transmissional losses  as well as creating simplicity in design by using parts readiliy available/ cannibalise from existing bicycles.
After simulating driving 1 wheel,I found it is enough to add value so why 2 is my reason to be energy efficient.You can see that the rear brakes is on the opposite side and no brakes on the drive side is to evenise wear & tear of the tires!
I just incoperated a 6 speed cog as an improvement to the rear 18teeth as found it a bit tiring trying to climb a 10degree hill recently.
Ist, I must tell you that Im a Lean person,and applies Lean thinking into design.  Simplicity in design identifying minimum resourse to eliminate Waste incoperating Robustness and also choosing parts that is repairable (should it fail at the momment it shouldnt( is part of Lean thinking.
Attached some photos.
God bless,
Tim