Enlarge / The Clip attached to a late-90s vintage mountain bike. (credit: Eric Bangeman)

Shortly after World War II, a French manufacturer by the name of Solex started selling mopeds. These were not your "typical" moped that looks kind of like a motorcycle with pedals—the mopeds made by Solex were essentially bicycles with a small, two-stroke engine mounted over the front wheel that could propel the rider around 100 km on a single liter of gas mixture. The downside: Solex mopeds were loud and cumbersome to ride due to the weight distribution, and they never really caught on in North America.

Clip, a startup based in Brooklyn, New York, has come up with its own twist on the Solex. Its only product, the eponymously named Clip, is a friction drive unit that attaches to the front fork of any bicycle, turning it into an e-bike. At $499 for the Commuter model and $599 for the Explorer, it is a relatively inexpensive way to turn just about any bicycle into an e-bike for a fraction of the cost of a new one.

The Clip mounts to the front fork just below the brake caliper. (credit: Eric Bangeman)

Weighing in at 8.8 lb (4 kg) for the Commuter model (the Explorer is a pound heavier), the Clip is at its essence a portable friction-drive. There's a detachable controller that mounts on the handlebar and the unit itself. The Explorer model, the one we reviewed, has a 192 Wh battery that takes an hour to fully charge. Its range is pegged at "up to 12 miles," a claim that is pretty accurate based on our testing, and the top speed is 15 mph. The Commuter model offers half the battery capacity, charge time, and range.