Bike Hugger 

The Ohm Sport XS750 is super-nice with a not so nice price tag (~$4000). Great bike though, with an incredible amount of power.

Ohm Sport XS750

If you haven’t been there yet, check out Electric Bikes NW in Ballard (formerly of Fremont). They’ve got a good selection and great staff. I bought a Giant LA Free Lite from them six years ago, and they were great. They sell both kits and complete bikes.

The question about build vs. buy is a tough one. It seems most of the electic bikes are spec’d with rather low-end kit.  I don’t mind simple, but cheap generally blows.

One thing to keep in mind with respect to components is that high-end light components are wasted on an electric. You’re adding ~20 pounds with the electric kit, so money is better spent on sturdy than on lightweight. As it happens, there’s some decent low/mid-range kit that’s pretty sturdy; you’d never consider putting it on a racer, but it’s probably fine for an electric.

Oh, and there’s a place in Maple Leaf that has some interesting e-bikes: LEV Seattle. I don’t think they sell kits, but the A2B bikes they have, I don’t think EBikes NW does.

Check the [Torker T3E](http://bikehugger.com/2008/11/huggacast-71-torker-t3e.html). It uses the Protanium system that has auto-assist at low speeds and a thumb-controller for boosting power. I don’t know if Torker is in production, but the Protanium is available on other bikes like the [Schwinn Electric](http://www.flickr.com/photos/huggerindustries/2495119762/).

It adds about 1K to the price of a bike. Also note there’s electric assist and then a hybrid drivechain like the Stokemonkey.

@rjl20 - I agree that I’m not going to spring for lightweight parts, but durable would be preferred.  Most of the bikes I’ve seen are spec’d with SUPER low-end Shimano stuff.  I’m thinking Deore/LX or so leveled stuff provides the strength for mtn-bike durability without too much gram-saving going on.

The kit in the picture looks like the Bionx. I would highly recommend it. I’ve been using mine daily for just over a year and have put 4000 miles on it in all weather, including a lot of ice and snow.

A lot of people like the fact that it has regenerative braking which adds about 10% to your battery mileage.

The smaller 250W hub motor plus Li-ion battery adds 14 lbs to your bike. This may not be enough if the hills are steep or you weigh a lot. I’m using the 350W kit, which adds nearly 16 lbs to your bike.

What I really like about this system is the torque senor. It measures the force of your pedaling and the system adds a certain percentage of electrical assist to your effort, depending on the chosen level of assist. The bike pedals exactly like a regular bike except now you are going much faster with less effort. It’s totally transparent.

I tried quite a number of electric assist bike and disliked the other approaches. Some, you feel power surging on and off, others do weird things at the wrong time and some just don’t feel like a bike.

Cost may be a consideration, though. I’ve now seen complete electric assist bikes with the same size motor and li-ion battery selling for the cost of the Bionx kit.

I don’t notice the weight of the kit, even when the system is turned off, unless I am picking the bike up or going up a hill. The range is great. In the lowest level of assist I get an actual mileage in my area ( no large hills) of about 45 miles. In my low-sweat assist level (level 2 on the Bionx), which I use when I cycle, say, 10 miles to meetings in my work clothes, I get about 30 miles. It goes up to level 4, which basically feels like an electric motorcycle and has a pretty short range. I generally only use levels 1 or 2.

In either case, I reach and maintain (on level ground) a cruising speed of 20 mph. This is the cut-out limit of the system in the US.

Since getting the system I have basically stopped using my car. I don’t think twice about running a round-trip errand of 20 miles. Because I’m biking so much, even with the assist I’m getting more exercise than I was before adding the kit. And it’s a LOT of fun.

Oh - a warning about any hub motor bike - you can’t put a hub-motor on the front if you have aluminum forks - it puts too much stress on them.

The Bionx has to be on the rear for the strain gauge to work.

Most ( all?) rear hub motors don’t work with cassettes, which means you have to acquire a freewheel, which you might not like if you have high-end derailleurs on your bike. It’s getting hard to find really small cogs on freewheels, so if you don’t have a pretty big chainring you won’t get a high enough gear to take advantage of the potential speed.

In my case, my biggest chainring is 48 teeth. I managed to find one of the few 11-tooth freewheels left int he world. This is just barely small enough to allow me to cruise comfortably pass 20 mph.