On-bike electric drives like the ConoDrive and Electron Wheel aren't the only means of adding some electric muscle to your pedaling. Powered bike trailers like the compact Ridekick or cargo-hauling Brouhaha bring their own drive wheels and give your pedaling a little extra oomph. The new, UK-designed Wheezy is a compact, easy-to-use electric trailer option. Make your bike a little more Wheezy and you can expect to be a little less so.

Since the Wheezy is self-powered and doesn't offer any built-in room to transport anything, it really isn't a trailer by any stretch of the definition, save perhaps for when it runs out of power. Its designers description of an electric auxiliary wheel is more accurate, but also clunky. We'll just stick with Wheezy.

The Wheezy is a compact unit that includes a single wheel with 9 x 3.5-in all-terrain tubeless tire, detachable battery pack, brushless electric hub motor, microcontroller, built-in charger with cable, and draw bar. A stainless steel chassis protects the components. Its 26-lb (12-kg) curb weight is a significant drop when compared to the Ridekick's 40-lb (18.1 kg) figure.

The Wheezy has been designed with both pedal sensor and thumb throttle options. The pedal sensor works like a pedelec bike, prompting the microcontroller to start the motor when you start pedaling. The thumb throttle lets you control motor power directly.

The initial set-up requires a bit of wrenching around, but after that, the Wheezy secures and detaches in a matter of seconds. The Wheezy mounting adaptor swaps out for the left nut on the rear bike wheel and the pedal sensor or thumb throttle gets mounted and wired back to the rear wheel. After that, the Wheezy simply snaps into place on the adaptor and plugs into the wiring. The two-axis joint allows the Wheezy to move left and right and up and down, improving handling on curves, turns and hilly terrain. A key-based power switch and battery lock system adds security.

The simple hardware means you can easily attach the Wheezy when you need it and take it off when you don't. You can also bring the Wheezy inside without having to roll the whole bike in or spend time detaching it from the frame. When it's off the bike, the draw bar works as a grab-handle, letting you roll the Wheezy around like a trolley. Inside, the charging cable pops out, and you can charge the battery in about 2.5 to 4 hours, depending upon the model's battery size.

Wheezy is raising money on Kickstarter, where it's offering the entry level Basic model at pledge levels starting at £259 (approx. US$400). It includes a 250-watt motor and a 166 Wh NiMH battery. It is only available as a pedal-assist (no thumb throttle) and offers up to 17.4 miles (28 km) of pedal-assist range and 15 mph (24 km/h) of speed.

The mid-level City5 includes a 250-watt nominal/500-watt peak motor, a 220 Wh battery, USB charging for external devices, two LED taillights and a 23.6-mile (38 km) pedal-assist range. Its top speed is the same 15 mph. It starts off at the £318 ($490) pledge level.

The flagship Touring7 has more power and all the bells and whistles. It includes a 350/700-watt motor; 280 Wh battery; USB, 12V and 110/230 V outlets; a Bluetooth transceiver and app compatibility; a 10 W LED headlight and two LED taillights; a carrier rack and bag; a 29-mile (46 km) pedal-assist range and a 20 mph (32 km/h) top speed. Kickstarter pledges start at £478 ($740). Both the City5 and Touring7 models work with either pedal assist or thumb throttle.

If all goes smoothly, Wheezy plans to begin deliveries by next May. However, with only about £1,700 of a £50,000 goal accounted for and two weeks to go, it looks like the startup will have to find funding elsewhere, likely delaying those plans.

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