[sinbad]

Have any of you ever put an electric motor on a bike? I have an old steel frame Trek bike that I was thinking of putting a motor on. Do you have an opinion about what motor would be best? My bike has 700cm wheels, which I guess might pose a problem. Thanks for your opinions.

 

[Geet]

I haven't done it, but I have a coworker who has. After seeing his get up I probably wouldn't do it to any bike.

With his setup he has a new front wheel that contains the electric motor. He has a very large 36 volt battery pack that straps to the back of his bike. The whole thing is extremely heavy. With this extra weight he has to use the motor assist most of the time.

His commute is about 2 km longer than mine and he does his in about the same time I do mine. I figure I could keep up with him for most of the ride. Of course if I really pushed him to use his battery, I could perhaps force him to drain it and then he'll have to pedal the rest of the way.

 

[fbagatelleblack]

Have any of you ever put an electric motor on a bike? I have an old steel frame Trek bike that I was thinking of putting a motor on. Do you have an opinion about what motor would be best? My bike has 700cm wheels, which I guess might pose a problem. Thanks for your opinions.

I used to be the lead engineer at Charger Electric Bikes, so I guess I've done this a time or two.

If you are in decent shape you probably won't get much benefit out of putting the motor on the bike. The extra weight of the motor and batteries will slow you down almost as much as the extra power will speed you up. You could probably see a 2-5mph increase in speed if you gear your setup correctly.

If you are looking for a moped, then there is some logic in putting on the electric motor. Nothing like being able to cruise with your thumb on the throttle.

My favorite retrofit kits were the 24V Currie Technology kits. They bolt on the back wheel. They look a bit funny, but they work really well. Unfortunately, they don't make them any more, but you can find used ones on eBay.

Good luck!

- Forbes Bagagtelle-Black

 

[undies]

There are a couple of regulars at my favorite tavern who ride battery-assisted bicycles. They each have what looks like an old dryer motor fixed above the rear wheel, with a friction wheel applying force to the tire. This is powered by a motorcycle battery attached within the main triangle. Everything is held in place by duct tape. Just think of the hours of CAD design that went into this arragement.

Frankly I don't get it; our town is flat and not very big. If one wants to experience the thrill of self-propelled two-wheeled travel there are these new contraptions called motorcycles that you can get now. Just a thought

I suppose it is only a matter of time before someone points out the similarity between electric motors on a bike and snakes on a plane.

 

[fbagatelleblack]

Frankly I don't get it; our town is flat and not very big. If one wants to experience the thrill of self-propelled two-wheeled travel there are these new contraptions called motorcycles that you can get now. Just a thought

Motorcycle = 180 (or less) hp, fossil-fuel-burning smog-spewing death machine which requires a driver's license. Cost is up to $30,000 or so.

Electric biycle = ~400W, clean-running, energy efficient machine which can be ridden by anyone 16+ with or without a driver's license. They are (relatively) safe unless you drive them like a maniac. You can get a lot of excersize on them, so they have potential health benefits. Great for people who want to get excersize while they commute, but aren't fit enough to do it on leg muscles alone, such as the elderly and handicapped segment of the population. Cost is less than $1000.

So, there are real reasons why electric bicycles make sense. These reasons are why they are selling millions of them in China, where bicycles are viewed primarily as commuter vehicles rather than excersize toys.

Yours,

FBB

 

[Geet]

Chainsaw motor

There are a couple of guys riding around Vancouver with bikes powered by chainsaw motors.

You can hear them coming from a long distance away. The bikes move at a pretty good pace though. In the end they are still burning oil and spewing exhaust.

 

[undies]

Motorcycle = 180 (or less) hp, fossil-fuel-burning smog-spewing death machine which requires a driver's license. Cost is up to $30,000 or so.

You should get out more

Great for people who want to get excersize while they commute, but aren't fit enough to do it on leg muscles alone, such as the elderly and handicapped segment of the population.

I would certainly agree with that. My "I don't get it" comment was directed more at the perfectly healthy guys living in the small, flat town who duct taped dryer motors to otherwise perfectly good bicycles.

 

[Dave_Stohler]

FWIW, road bikes are the most efficient machine known to man. Electric motors are, at best, only about 40% efficient.

 

[fbagatelleblack]

FWIW, road bikes are the most efficient machine known to man.

Almost correct. They are the most efficient vehicle yet invented (That I know of, anyway).

Electric motors are, at best, only about 40% efficient.

Incorrect. Electric motors can have efficiencies in the high 90's, percentage-wise. Even a standard, off-the-shelf NEMA B motor can have efficiencies in the 90's. See:

http://www.engineeringtoolbox.com/electrical-motor-efficiency-d_655.html

Internal combustion engines top out in the 45% range, or thereabouts.

- FBB

 

[fbagatelleblack]

You should get out more

Ouch! HEY! It's been raining, okay?! And I've really turned into a Californian over the last few years - a little bit of drizzle and I stay indoors playing computer games. I was going to go on a killer ride tomorrow, with ~4-6K feet of climbing, but there is a storm moving in, so I guess it's a big breakfast and then I'll finish conquering Northern Europe. If it clears up in the afternoon, I'll get out and go for a ride.

And I'll continue to like e-bikes even if they're not cool.

Yours,

FBB