Sanity check?

[drewdiller]

Hi, I've been lurking a while, but I want to ask a basic question, sort of a "state of affairs" question.

First, (a little) context:

I am decent shape, former competitive runner. I aim to regain "great" shape, but it's not something I want to do to and from work. I've been biking off an on this summer: I've observed that as I age, the drivers in this place get worse and worse. If I can avoid their routes and traffic jams, my homicidal urges stay well maintained.

My commute is 7 miles each way. Down the valley in the morning... UP the valley in the evening. Lots of wind by the Mississippi. Snow to handle (I live in Minnesota). Very safe route, only four traffic intersections.

I just want to get home in a relative hurry.

I don't have any CNC skills. I have a single speed bike with disc brakes front and rear (pics).

The question: Is it possible to do an e-conversion that adds 15 pounds or less to my bike and has an emphasis on high torque as opposed to top speed, and come in at a total cost under $1,000, the further the better?

I am aware of light weight DeWalt batteries with A123 cells, fixed sprocket adapters for existing hubs, stuff like that, I just want to know if the italicized is a realistic goal.

Feel free to call me stupid. I dropped out of engineering school for reasons unrelated to engineering school, and now I very much regret it. I write website software for a living, it's a pseudo science. Speaking of, if you need CSS or Javascript help, feel free to PM me.

 

[liveforphysics]

If you search for Grinhill's lightweight commuter bike (his first one), you will find what you are looking for.

I think he may have added less than 5lbs total to the bike, including battery?

You can put together an RC motor setup with LiPo batteries that weighs less than a small hubmotor alone with no batteries.

 

[gogo]

http://www.goped.com/Products/GoBike/default.asp

 

[boostjuice]

http://www.endless-sphere.com/forums/viewtopic.php?f=28&t=10635

I agree with LFP. Grinhill has one of the cheapest and highest power-to-weight systems ive seen on these forums.

 

[deardancer3]

A new entry, no one has tested:

http://endless-sphere.com/forums/viewtopic.php?f=7&t=13333

 

[drewdiller]

Thanks! I might PM Grinhill, I have a few questions whose answers I haven't found in his threads...

I had thought of a variation on a friction drive system... driving the tire directly is not an option to me because of studded tires potentially ripping up the driver, and vice versa with premature stud wear. Why not drive the rim itself using opposing small wheels?

The more I thought about it, there were problems that didn't sound fun to solve: ensuring that the rim is _always_ perfectly true, being able to disengage the rollers for human-only efficiency, figuring out how to align the contact surface of wheels to be parallel with the rim, etc.

(And, somehow, I have a feeling it is not an original idea anyway)