Power-to-weight ratio is a measure we're used to hearing in conversations about ultra-powerful supercars subjected to lightweighting programs, but British e-bike manufacturer Prodrive brings it to a discussion about small, folding e-bikes. A follow-up to the "world's lightest folding bike," the Hummingbird Electric is billed as the world's lightest folding e-bike. With a weight of just 23 lb (10.4 kg), it doesn't need the biggest motor in the garage to flaunt its power-to-weight ratio proudly.

When Prodrive announced production of the 14.8-lb (6.7-kg) Hummingbird folder in 2016, it had developed a solidly light bike, but its claim of "world's lightest" wasn't without dispute – the older 12-lb (5.4-kg) A-Bike seemed to have it squarely beat. Given the A-Bike's rather strange layout, you could say, somewhat fairly, that the Hummingbird is the lightest traditional folding bike and the A-Bike is the lightest ... something else.

At just 22.7 lb (10.3 kg), the carbon-framed Hummingbird Electric has the electric version of the A-Bike squarely beat, coming in over 3 lb (1.4 kg) lighter than the latter. But there is at least one folding electric bike standing in the way of an undisputed claim to the "world's lightest folding e-bike" crown – the 15.4-lb (7-kg) Smacircle S1. Here again, Prodrive can perhaps add "traditional" to its claim, leaving the S1 to the "something else" category.

Suffice to say, the Hummingbird Electric is lighter than your typical folding e-bike. And it isn't noteworthy only for its low weight but also for the pure simplicity of its design. A rear hub drive houses both the 250-watt motor and the 160-Wh lithium battery, providing a clean frame with no added battery pack jutting out or hanging off. This maintains the bike's sleek geometry and simple folding dynamics.

Building one of the world's lightest electric folders means slimming down on components, and Prodrive relies on a Bluetooth-connected smartphone to serve the role of bike computer. Riders can use their phones to control power, monitor usage, run navigation, perform remote diagnostics, and lock up the rear drive wheel for security.

The motor is operated by a pedal-assist drive that the rider can activate by performing three consecutive backpedal revolutions after getting speed up to 5 mph (8 km/h). The motor then adjusts assistance based upon rider input and shuts off automatically after two minutes of inactivity. The bike has a top speed of 15.5 mph (25 km/h) and provides up to 18.6 miles (30 km) or so of electric-assisted range. The battery charges within about 2.5 hours.

Given its small size and limited range, the £4,495 (approx. US$6,000) Hummingbird Electric won't fit the needs of every bicycle commuter, but it does seem like a particularly interesting option for those who have urban commutes that involve any mix of bicycling, public transportation, staircases and pedaling/walking through tight spaces.

Source: Prodrive

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