Electric front and friction rear?

flossandfly

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Jan 2, 2012
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Hi, I have an older style mountain bike (no disc brakes, no suspension) with a robin subaru friction kit from statoninc on the back. It works well to help up some big hills on my commute home. But it is not allowed on the bike paths so I thought I would put a front hub electric kit on the front for the bike path part of the trip.

I just want some advice in case this is a stupid/dangerous idea. The RS friction kit adds about 22 lbs and a front hub kit with battery would add more weight. (another 20 lbs???) A smaller watt kit would be lighter, but the battery is probably the bulk of the weight.

If it is a good idea, what are some good kits and from where?
 


graucho

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Feb 14, 2008
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The robin subaru friction kit takes up the rear fender space where the battery pack would normally go. I like the idea of a hybrid bike. The weight added wouldn't be any different than a 260lb person riding the bike. Figure out a good space to add a battery any you should be able to a good 15-20 mile of silent riding.
 

darwin

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May 26, 2008
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How do you keep both power plants in sync without a $5000 controller and monitors?
 

graucho

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Feb 14, 2008
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How do you keep both power plants in sync without a $5000 controller and monitors?
Not a "true" hybrid.
I'm sure i'm preaching to the choir with most here. But for those learning about this setup...
I guess the term hybrid when talking about bicycles is your using one or the other. (not a true hybrid) Not like a car when they switch over automatically. The bike's front electric has its own controller. And the rear is gas without a controller. Since they both have separate throttles I guess you could be the controller.:D With a little practice backing off on one while while juicing the other, and vise versa. I had a dual system 2 years ago but I killed the gas, stopped the bike and released the roller tension to the rear wheel then went electric down the walking/biking trail quietly not causing a ruckus.
 

laugh

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Jan 17, 2013
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46
I have been thinking about this lately as well. My thought would be to use a hub motor kit with two batteries of the same size. Attach a mounting bracket to ether side of your front fork (think touring panniers) attach the throttle for the electric to the left handle bar and the throttle for the gas to the right. and there you have it the extra weight over the front wheel might seam a problem at first but I have been using a front rack for years with little ill effect. Have fun with the build and remember that no plan survives the first contact with the enemy.
 

wheelbender6

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Nov 13, 2008
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I considered adding a 24v electric motor to the front of my gas bike for sidewalking (the only safe way for me to commute to work). I have a China girl 2 stroke and there is a lot of drag when the motor isn't running. I tried to find a Hybriped sprocket (allows the motor sprocket to freewheel with no drag) but nobody seems to import them to the US anymore.
If you are able to easily lift the motor off your rear tire for pedaling, a front hub motor may work for you. Seems to me that you have the best of both worlds if you have the range of a gas engine as well as the ability to silently power your way down the sidewalk and multi-use path. I would probably go with 24v to keep the weight down.
I will probably just build myself an electric only powered bike for commuting on the sidewalk.
 

Dankoozy

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Dec 28, 2012
Messages
114
are you going to be removing the engine altogether for use on the path? I thought of drilling a 6-8mm hole in the roller, tapping some thread into it, and finagling some sort of a DC generator onto the other end. I don't know how long these paths are but it would mean you could get away with using a smaller battery. A bunch of 18650's, NimH D cells or even lead acid. The batteries could help balance the FD kit as well.

I just don't like the hub motors in front at all unless you're going to reinforce the forks. If you're not removing the engine you could have a DC motor powering the other end of the roller
 
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