Thinking about electric assist

Okay on the flats, but for the hills we'll need more power

If I could name the #1 thing that makes parents we know in San Francisco who’ve never attempted family biking perk up and say they want to try, it is the words “electric assist.” The other week I said those words in passing to another mom at our daughter’s preschool who has almost no experience riding. She has now told me every day that I’ve seen her since that she is hounding her husband to shop for an electric bike for them when he returns from his current business trip.

Discussions about riding bikes in San Francisco always involve hills, to some extent. This is especially the case if you live, as we do, on a mountain. Mt. Sutro: it’s right there in the name. It burns us, Precious! We’ve learned to ride them, but these hills aren’t easy. If we lived higher up the mountain like some of our neighbors, I would be riding an electric bike right now. Nonetheless hills are at least consistent. Unlike the wind or the traffic, they are predictable. They aren’t going anywhere. I keep thinking that people can get used to anything, but there are destinations in the city we avoid unless we’re driving. And there are times we give up. Last weekend Matt couldn’t face the prospect of riding to the hardware store, which is halfway up the other side of our hill, leaving him the unenviable choice of riding up and down and back, or down and up and back, or driving. Despite the hell that is finding parking in that neighborhood, he drove.

It's easier on the way down

Our friends have a Big Dummy to take their kids to school, and they live on Lone Mountain. They take their kids, their groceries, and on occasion each other, up Lone Mountain. And they tell me they push that bike a lot. They are philosophical about it and call it upper body training. They are opposed to many electric assists for environmental reasons, but they are the exception. Our friends who live on Potrero Hill or nearer the top of Mt. Sutro have said they’d be riding their bicycles daily if they had any idea how to arrange an assist. I myself had no idea. But our kids are getting heavier, and I think it’s time to learn. The only other semi-practical option was suggested by my brother-in-law, who noted that Lance Armstrong became a much better hill climber after getting cancer and losing 20 pounds. I suppose that I could conceivably hack weight off my own frame for a year or so at the same rate my kids were gaining without losing much leg strength. But as a woman in America I really don’t need any more reasons to obsess about body weight, and this strategy would only work for so long anyway.

Option #1a: Buy a new electric bike. There is a new shop (and some established ones) in San Francisco dedicated to electric bikes. But when I look at their bike lines, they do not seem practical for family use. Most seem to lack basics like rear racks, and overall remind me of the Bikeyface cartoon about “ordinary black lace panty” bikes (not that there’s anything wrong with that). Perhaps one day this will change.  But the word on dedicated electric bikes is that the bikes themselves are often cheaply made. To keep the price point less terrifying, the money is in the motor.

Option #1b: Buy a new electric cargo bike. Both Kona and Yuba make electric cargo bikes, the Electric Ute and the El Mundo, respectively. These are obviously suited to family use, and they are both respectable manufacturers who primarily make bikes rather than slapping some bike components onto a motor. These bikes are expensive relative to the non-electric versions (all electric bikes are expensive) but they seem to offer some economies of scale; the electric versions cost less than it would cost to buy a non-electric version and add a comparable motor to it. If you’re looking for a new cargo bike, these seem like competitive options. However we have a cargo bike that we like, and living in the city makes us reluctant to commit to a really long bike like the Ute or the Mundo.

Option 2: Add a motor to the bike. This is the direction we’re leaning if we electrify: we have bikes we like right now, and if we wanted to upgrade/change bikes later, we could move the motor, potentially sparing ourselves the cost of upgrading more than once. But the market for add-on electric assists is massively confusing to me. Older reviews suggest that some manufacturers offered pedal assist (e.g. BionX, Stokemonkey) and some offered throttle assist (e.g. eZee, nearly everyone else). Not sure what’s up with the random capitalization by these manufacturers. What that means as I read it:

  • pedal assist motors make you stronger as you pedal, but won’t work unless you’re pedaling
  • throttle assists operate with a switch on the handlebars and move the bike along whether or not you’re pedaling.

But evidently this is moot now because primarily pedal-assist motors now offer the option of moving your bike whether or not you’re pedaling (BionX) and primarily throttle assist motors now offer what some are calling “the European option” of only working when you’re pedaling (eZee), a term which I can only assume refers to some legal restriction on electric assist bikes in Continental locales. As a bonus, the major brands all seem to offer head and tail lights that plug into the battery. Whoo hoo!

As a result I have started thinking about electric assists in the simplest possible terms for a total noob like me: front wheel, back wheel, and inbetween.

Front wheel motors

You can buy these all over the place, including on Amazon; eZee is apparently the market leader. The El Mundo uses an eZee motor; some models are evidently powerful enough to move a loaded cargo bike. An important caution: You shouldn’t put a front wheel motor on an aluminum front fork. It will break while you’re riding and fling you headfirst onto the ground. GOOD TO KNOW! This is mentioned occasionally on sources like online bicycle forums and on the websites of what appear to be reputable electric bike shops, but is not routinely mentioned in the advertising for these motors. The electric assist market is a Wild West indeed.

Costs for these motors seem to range from $400 or so for a low-power version with heavy batteries (not cargo-bike friendly) to $1500 or so for a high-torque version with lighter weight batteries. Installation not included, and given that people are evidently mounting them on aluminum forks on occasion, I would be inclined to find a reputable bike shop for installation even if I weren’t hopelessly unhandy. Who knows what else could go wrong?

The Kona has an aluminum fork: no front wheel motor on our MinUte. The Breezer has a steel front fork (the specs said “chromoly” which I had to look up, because in case it’s not totally clear by now, I’m clueless; another option is to see if a magnet sticks to your fork, if yes, your fork is steel). So we could put a front wheel motor on the Uptown.

Rear wheel motors

The market leader in rear wheel motors is apparently BionX. It is primarily a pedal assist motor, but the newer versions claim you can use it without pedaling if you want. The BionX motor comes in various powers, some suitable for cargo bikes and hills, others less so. BionX appears to be sort of the Apple of electric assists; expensive and incompatible with other systems, but stylish and easy to use. The newest versions have cool features like locking the rear wheel when you walk away with the console, making the bike more difficult to steal.  Reviews suggest that riding with the BionX is a lot of fun; you pick a level of assist (25% extra to 300% extra) and when you push down hard on the pedals, the battery sends out that much extra power to make riding easier. This would be super-handy at stop lights as well as on the hills. This motor only works on bicycles that use a derailleur on the rear rather than an internally geared hub.

Cost seems to range from $1000 for a system that might not move a loaded cargo bike uphill to $2000 for the top-of-the-line system with lots of torque and security features, installation not included.

My Breezer has an internally geared hub and I like it: no BionX for the Uptown. The Kona MinUte has a derailleur so we could put a rear wheel motor on it. How can you tell if you have an internally geared hub? It’s like true love; you already know.


Let’s say you have an aluminum front fork and an internally geared hub and no desire to buy a new bike. Or you are carrying very heavy loads. Apparently there are also motors called mid-drive motors that attach to the chain. They are recommended for cargo bikes because they have a lot of torque. The only two I have heard of are the EcoSpeed and the now-out-of-production Stokemonkey. The Stokemonkey, if it were possible to find one used, is pedal-assist only (a discussion of the pros and cons of this for one family, relative to the eZee kit, is here). And evidently really, really powerful; it took a loaded cargo bike up Russian Hill! That’s over a 30% grade.

Costs are heart-stopping even for electric assists. The EcoSpeed runs over $3k. Installation is evidently challenging. It’s not for the faint of heart, unless of course you live in Portland, where all these motors are made, and where presumably any bike mechanic could install one with their eyes closed in exchange for a pint of artisanal beer sold from a Metrofiets.

Should we get an electric assist? I don’t know. They’re expensive, and that’s daunting. But we’d probably ride a lot more, and that is worth something too. We fear the hills more and more as the kids grow. We are fortunate that there are at least bike shops in San Francisco that seem to specialize in electric motors. Both Big Swingin’ Cycles and The New Wheel will put a BionX on a bike, and Electric Bicycle Outlet will install an eZee kit. Maybe it’s time for us to actually visit one of them.


Filed under cargo, electric assist, family biking, San Francisco

2 responses to “Thinking about electric assist

  1. Ann

    I have a front motor (Ezee) on an aluminium fork. There are different opinions whether this is safe or not. Before installing the motor, I spent hours reading on the Endless-sphere forum:
    What I learned is that basically a front motor on an aluminium fork is fine unless you have a very powerful motor (1000W or more). You need to install it correctly and use a torque arm. I probably wouldn’t trust a shop, unless you know that the mechanic has plenty of experience installing that particular motor. Installing an Ezee kit is quite simple, and it’s easier to check your own work than somebody else’s.

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