Should I Motorize My Bike?

September 21, 2005 7:38 AM

I'm much too nerdy to get a real motorcycle, but I was thinking about somehow slapping a motor onto my bicycle. Has anyone had any experience with motorizing bicycles? Any recommendations?
posted by hughbot to Sports, Hobbies, & Recreation (25 answers total)

Now, now, let's not stereotype. I'm a nerdy copy editor, for crying out loud, and I ride a motorcycle. If you're dead set against a real motorcycle, though, consider a scooter.

Adding a motor to a bicycle makes the bike very heavy. Also, they make a shrill, headache-inducing high-pitched whine. I wouldn't recommend it, myself.
posted by scratch at 7:59 AM on September 21, 2005

Someone on bikeforums.net might be able to help you. Though I think you'd be better off buying a bike that already has a motor or buying a scooter. Strapping an engine of any sort to a bike will throw the balance way off changing steering and just the riding.
posted by drezdn at 8:13 AM on September 21, 2005

I don't think the frame, brakes, wheels and parts of a regular bicycle could hold even a small engine. It probably can be done but you'd be better off in a Vespa. You know you can get a Harley Sportster for <$10,000.
posted by geoff. at 8:15 AM on September 21, 2005

Nobody is too nerdy for a motorsickle, friend. Besides, aren't 2-stroke engines responsible for a lot more air pollution than 4-stroke engines? Get that motorcycle, or at the very least, a 4-stroke scooter.
posted by NoMich at 8:17 AM on September 21, 2005

Vespa, baby.
posted by o2b at 8:37 AM on September 21, 2005

Yeah, get a Vespa. You'll have plenty to work on with one of those.
posted by trbrts at 8:41 AM on September 21, 2005

There are definitely ways to do this, out there. Or at least there were.

Many years ago, a friend of mine had a weird little 2-stroke engine that was mounted to the luggage rack of his dodgy old bike. It powered the bike by a drive wheel that ran against the bike's rear wheel. There was some sort of accelerator cable/control thing that mounted to the handle-bars. The first time that I saw (and heard) it, I laughed non-stop for an hour.

He was inordinately proud of it, and used it for quite a while, motorvating himself around a large military base. He also took a lot of ridicule. Lots and lots of ridicule. Just thinking about it, brings back memories of listening to the sound of him approaching, as if he was being pursued by a swarm of angry bees.

The whole sorry business ended due to an unhappy convergergence of poorly maintained (and way overstressed) brakes, alcohol, and a couple of angry MPs.

Happy days. Thanks for cheering me up.
posted by veedubya at 8:43 AM on September 21, 2005

There's also the small problem of a bicycle + engine is a moped, with its attendant tax/insurance costs.

Engines are for wusses. Use your legs.
posted by scruss at 9:09 AM on September 21, 2005

Who says "motor" means a gas motor? Electric motors are basically silent, and you can use regenerative braking to charge the batteries back up.
posted by Mars Saxman at 9:14 AM on September 21, 2005

I rode an electric bicycle for a year and a half or so. It was an older but well respected engine (US Currie Pro-Drive), and there were some good things about it. However, it was never a substitute for a motorcycle. I could ride pretty fast on the flat (18 mph) without pedaling, but any kind of hills required quite a bit of assist by me.

Now I ride fixed gear. It suits my needs much better: suitably geeky plus I get plenty of exercise. I reccomend it.

In the mean time, it is possible to mount small engines to bicycles. Rather, get yourself an old moped. They're very geek chic these days.
posted by daver at 9:29 AM on September 21, 2005

You need a Velo Solex! (warning: background music), although there doesn't seem to be many places to shop for one online.
posted by bering at 9:31 AM on September 21, 2005

Check local laws. In some jurisdictions, putting a motor on a bicycle basically gets you the worst of the bicycle, moped and motorcycle-related laws combined; you're still a second-class road citizen because you're a bicycle, but you lose the advantages bicycles have like bike lanes and bike paths. YMMV, of course, but be sure to research that first.
posted by mendel at 9:44 AM on September 21, 2005

No. Get a motorcycle, or, if you must, a scooter. Motorcycle insurance is dirt cheap as long as you only carry liability. I pay $80/year for my '83 Honda Nighthawk. Besides, no one wants to ride on the back of a scooter.
posted by electroboy at 10:24 AM on September 21, 2005

I recommend using your legs as the motor. Obviously, they'll have to be upgraded. To do this, ride more.
posted by recursive at 10:45 AM on September 21, 2005

Don't get a vespa. Vespa = trendy BS.

Get a used honda scooter.
posted by delmoi at 11:01 AM on September 21, 2005

A honda metropolitan or ruckus goes for about $1k on ebay.

If you just ebay for 'moped' you can find some cheap, old junkers for a couple hundred For example, here's an '86 honda elite 80 with 6k miles for $300, but the auction ends in 4 hours.
posted by delmoi at 11:08 AM on September 21, 2005

You could also get somethign like this if you want to UP your nerd chic factor.
posted by delmoi at 11:11 AM on September 21, 2005

i got the electric bike kit and battery from goldenmotor.com and have put over 500 miles on it. electric bikes are great because you dont have to get insurance or a license, they cost pennies to recharge, can get over 30 miles range, and they are discrete. The downside is lead acid batteries are so heavy, the bike ends up weighing 100lbs, and everything that can go wrong with it has, but its very easy to fix. I want to get some Li-ion batteries, which are about 20 pounds lighter, but theyre expensive up front. if i could go back and do it again, id probably get one of their complete e-bikes, theyre lighter and better constructed.
posted by psychobum at 11:12 AM on September 21, 2005

this page has lots of info on actual electric bycicles.
posted by delmoi at 11:14 AM on September 21, 2005

I'm definitely biased on this one, but I say just buy a motorcycle. You can get a good used one for about the price of a new scooter (or less). The thing about motorcycles is, no matter how nerdy you are, most other riders will wave to you as you pass. Also, women will ride on the back with you. For a starting bike, I recommend something akin to an 80's model Kawasaki KZ440. If you're an average size, you can zip around just like you were on a scooter, but 2-3 times as fast.

If you're really set against a motorcycle, you might consider something like a light pedal assist (LPA) bike. You can probably pick one up at a junkyard or something and fix it up pretty easily. As for just motorizing an old bicycle, there are transmission issues. You need quite a bit of torque to get started, and less once you get going. LPA solves this by having you pedal up to speed, then it takes over, rather than having gears to multiply the torque. Also, when you come to a stop, if you don't have a way to disengage the engine from the drive wheel, you're going to stall. In short, you can't just glue a lawnmower onto a bicycle and call it quits.
posted by dsword at 11:25 AM on September 21, 2005

I'd recommend not doing it. I've seen a few electric and gas refits on bikes (never actually ridden one). You wind up gaining just enough power to avoid working, without having enough to really participate in traffic as a motor vehicle. The bike is no longer very serviceable as a bike, and the refit involves a lot of cranky parts. A roller driving the tire directly? fuggeddaboutit. You'll be buying new tires monthly.

Get a scooter. Vespas are very pricey, even used, but there are scads of other brands (from China, Korea, India, whatever) out there for a lot less. Or get a motorcycle. Check craigslist.
posted by adamrice at 11:30 AM on September 21, 2005

Take an MSF class, then see if you still feel too nerdy.
posted by yetanother at 11:38 AM on September 21, 2005

Not recommended.

Humans produce low power at high torque, and bicycle drivetrains are optimized for this (which is why the chain/derailleur design hasn't changed significantly in decades.) Electric and gasoline motors produce high power at relatively low torque, requiring a different drivetrain altogether.

Besides, there are lots of electric bikes or small motorbikes that should meet whatever need you have. Unless you're doing it for fun, retrofitting is simply not worth the bother.
posted by randomstriker at 12:33 PM on September 21, 2005

I have a buddy in Victoria who's really into this. He's even thinking of setting up shop selling the kits and completed bikes.

The EVSolutions one are apparently top-notch. It's a kit you can put onto a normal, existing bike. They are well designed for quietly assisting bike riding: they can be used 100% for the steepest hills, and have the torque to get you up them, or can just be used to assist your pedalling so that the high-grade hill feels like a low-grade hill.

They also have good speed, and are fairly unobtrusive- you don't have some huge pack or bulky apparatus. The downside is the weight, but the EV ones apparently weight 50-60 pounds as a full bike, so it's not completely immovable.

Technicalbikes.co.uk (which appears to be down right now) has some great vids of their mods, showing off the speed and the torque to get up and down steep hills.
posted by hincandenza at 2:35 PM on September 21, 2005

On the Motorcycle vs Scooter front. Get a motorcycle, most have have bigger wheels than scooters, which means they handle decaying roads better, most also have more power than scooters, which gives you more juice for escaping clueless automobile drivers.
posted by Good Brain at 11:28 PM on September 23, 2005