How I converted my vintage Peugeot City Express to a 30mph Electric Bike for under $500

I live in NYC and constantly see restaurant delivery guys zipping around on bicycles. The day I first saw one of them accelerating without pedaling, a seed was planted in my mind. That seed has grown into a small tree resembling a very fast bicycle.

There are many benefits to biking in NYC, only some of which are provided by a motorcycle, and all of which are enhanced by adding an electric motor.

  • Avoiding traffic by having a choice between the regular street, bike lane, or (illegally) sidewalks, going the other way on one ways, etc
  • Not having to find car parking
  • Not having to pay for the subway
  • Not having to ride on the subway
  • Not paying insurance
  • Not needing to have a driver’s license

I did a lot of research before buying my bike and decided I wanted

  • At least 48 volts, 1000W for speed, my size, and range
  • Easy installation (I don’t know much about bikes)
  • Relatively Cheap
Kits like these are plentiful on eBay and Amazon

I chose to have a 1000W 48V front wheel hub motor kit for my ebike which I purchased off eBay for $151. It’s important to note that most ebike enthusiasts would recommend a mid-drive motor or a rear-hub motor. However these are more complicated to install and usually more expensive. I don’t know much about bikes so I chose a front wheel kit with the entire wheel and tire. The kit I got included everything but the battery and torque arm.

  • Motor built into wheel, with tube and tire already mounted
  • All necessary wires, which are color coded and plug and play
  • Twist throttle with on/off switch and 3 color LED battery level indicator
  • PAS: Pedal Assist Sensor (I didn’t install this)
  • Controller
  • Brake handles (cuts power to motor when braking)
  • Zip ties
  • Bag to hold controller and wiring
How a torque arm works
How a torque arm works

It is important to have a torque arm (or even two) if you are using a front motor! Otherwise the motor can snap the dropouts (where the axle of the wheel fits into the bike frame) causing the wheel to fall off the bike while you’re riding it and sending you flying over the handlebars at 30mph which could literally kill you.

Torque arms cost less than $20 so this is a no brainer. Since my frame is steel I went with just one torque arm, if your frame is aluminum (it probably is) you should probably get two.

Electric bike batteries are very expensive, usually the most expensive part of an ebike by far. You do not want to by old school lead batteries as they are heavy as hell and they won’t provide as much power or range, and they’ll be dead faster.

I learned a lot about batteries in general during my ebike research and especially rechargeables which are most often comprised of multiple 18650 cells, which power everything from box type handheld vaporizers and flashlights (1 cell) to ebikes (approximately 52 cells) to Tesla Model S (approximately 6800 cells).

A popular place to buy new batteries is Luna Cycle or em3ev.

Ebike battery
This looks pretty much like the battery and charger combo I have

I got a used one on eBay which has so far turned out to be a great deal. It is 48v (though it was listed as 52v) and 13.5ah. The volts are the power, the amp hours are the range (I think.) I paid $312 with free shipping. I think this is probably about a $500 battery/charger set (new, at the time). So far so good. My battery came with a mount which screws into water bottle holes on the frame. The mount has wires to connect to the controller. The battery then slides onto the mount and secures with a lock and key. One issue I’m having is with the small plastic clips which hold the battery to the mount – so far 2 out of 6 have broken off while I was carrying the bike (I keep it inside and have to go upstairs).

My kit arrived first, which gave me time to install it all nice and clean on my bike.  First problem – the axle didn’t fit in my frame dropouts.  Good thing I have a rotary tool AKA a Dremel (mine is actually Black & Decker).  I grinded off the paint from the dropouts and the wheel fit in.  My daughter enjoyed watching the sparks fly 🙂

Inexpensive suspension seatpost

The battery came a couple days later and I was super psyched for my first ride.  It was amazingly fun. But extremely bumpy.  I decided to get a seatpost with suspension.  These can be quite expensive (over $100) and I imagine that the very expensive ones feel like riding on a cloud.  But I didn’t want to spend that kind of money so I got one on Amazon for about $30.  It definitely helps a lot,  potholes no longer feel like I’m smashing my tailbone with a hammer.

The back part is (fairly) easily removable

I also got a padded seat to mount on my bike’s rear rack so I can take a passenger.  You’ll also need some bike pegs for your passenger to rest their feet.  While you definitely feel the speed reduction when carrying a passenger, it’s still powerful enough to get going faster than I could by pedaling solo.  I modded it with some thumb screws so I can get the backrest on and off easily.

I have hit a top speed of 32mph on my ebike which feels VERY fast.  Don’t forget to wear your helmet!