Tuesday, November 10, 2009

TIme to get serious - electrify the trike!

As detailed in my previous post I have been without the trike for a few months and I have certainly missed it! Needing to use the car even for short shopping trips and school pickups has taken its toll on my fitness level and our petrol consumption! While the Mountain Drive issue was being rectified I thought it an opportune time to further explore ways to improve the trike.

With the Mountain Drive whilst I can go up any hill I want it can take a long time to do some of my regular trips when only traveling at 4km an hour! The kids can get restless when going so slow and it can also be embarrassing being overtaken by old people going for a walk! So I have been looking at installing some form of electric assist system that could increase my speed up the hills to say 15-20km/h with me also pedaling. I do not need any assistance when on the flats or downhill as the trike fairly flies along in these situations even with a heavy load.

The two main options for pedal assist are the use of a 'through the gears' type of motor that drives the cranks or a hub motor that sits inside a wheel.

Through the gear options include the Cyclone, Epac or Elation type of systems that in various ways drive the front cranks or the chain line. Advantages of these types of systems are that -
  • You retain the use of all the rear gears
  • The motor can take advantage of the rear gears to provide better assistance
  • You can choose to use only the motor, only pedal or a combination of the two
  • Most of these systems use a freewheel system so there is no extra drag if you chose not to use the motor
The main disadvantage of these types of systems for me would be the difficulty in fitting them due to the non standard frame on the trike and that most would necessitate the removal of the Mountain Drive to have 'normal' cranks. However during my research on motors I came across this setup which is a custom built variation based on the above systems. It is fitted to a trike similar to mine with a Mountain Drive installed. However it does not 'freewheel' meaning the pedals always turn when the motor is engaged. The owner of that trike kindly answered a lot of my questions during my research on the best system for my trike!

Hub motor options are too numerous to list here! The main trouble with these for my setup was that I could not use them on the front wheels as there are no suitable forks to mount them on. This would mean replacing the rear wheel which on my trike has the hub gears and back pedal brake. Thus if I was going to install a hub motor I needed to examine converting the trike to a derailleur gear system. Unfortunately the trike has no derailleur hanger on the rear dropout but thanks to the late Sheldon Brown's informative web site I learned about 'adapter claws' and I managed to track one down from this ebay shop for only $US10. I also managed to find another Christiania Trike that had a rear hub motor installed and noticed his use of a rear rim brake mounted in a way I could replicate. With my recently upgraded front brakes I would rarely need a rear one but it would be nice to have it as a backup!

So after much googling and reading of various e-bike forums I started asking questions of Renaissance Bikes about the Ezee Geared Hub Motor Kit. These hub motors (as opposed to 'direct drive' motors) have a planetary gear system built in which means more 'torque' for getting up the hills. The motors are also smaller and weigh less then the direct drive types and thanks to the built in freewheel they have no drag when being pedaled without the motor engaged. I cannot speak highly enough of the people at Renaissance Bikes - they answered all my queries very quickly and were a great help in sorting out the best options to put on the trike. I went for a rear motor with a controller from a front motor kit as the longer cables on the front controller will enable me to mount the battery in the front box if I choose. I also purchased a cycle analyst so I can accurately monitor power usage and limit the motor to make it street legal.

And would you believe the motor arrived the same day as the repaired Mountain Drive. I paid for it on October 30th, it was built (I needed the 26inch motor relaced into a 24 inch wheel) and then shipped from Canada on November 7th and I got it about 11am on November 9th! Incredible service. A couple of items were missing however (a rear torque arm and the 7speed freewheel) but after letting them know I was advised they would be sent out that day and they are now on the way.

The motor in the 24 inch wheel can be seen below. It has a fairly small diameter compared to non-geared motors and in fact is about the same size as a disc brake rotor -

The battery for the motor is contained in a neat bag that can be attached to a rear rack though I am likely to mount mine in the cargo box. A flap allows access to the charging port -

Now it all just has to go together! Simon at Cycle Surgery is going to do the Mountain Drive install, swap the rear wheels and install the derailleur. When that is all sorted I'll work out the best way to install the battery, throttle etc. Stay tuned for updates!

PS - I would like to thank my lovely wife for letting me buy the above! It will be great honey - trust me!

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