Upon first hearing about the Fly Kly Smart Wheel, we were more than skeptical; we called straight BS. The Kickstarter-darling, which reached 700 percent of its funding goal, claims to transform nearly any regular pedal-powered bike into an e-bike capable of zipping through the streets at speeds upwards of 25mph. But we all need to be humbled every now and again. And we'll come right out with it: the wheel works. And it works well.

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Inside the large rear hub is a detachable 36-volt lithium battery and a 250-watt motor with enough juice to move you at 20mph for 30 miles. (The battery charges in about three hours via AC outlet, but if it dies on the road, pedaling or coasting downhill also rejuvenates it.) The SmartWheel works with just about any bike right out of the box and comes in three of the most popular bike tire sizes - 20, 26 and 28 inches. It slips into the rear dropouts like any other wheel, attaching with bolts. Simple. Even simpler: It's all controlled by your phone, which sits in a handlebar-mounted dock/light that's wired to the smart wheel. Pair your phone to the wheel (it is Bluetooth compatible) and an accompanying app works like a dashboard listing current speed, distance travelled, and battery life. It can can also "lock" the rear wheel - a passive theft deterrent - and track it if it does take a walk. The motor kicks in as soon as we started pedaling, offering enough power so that even hills felt like gentle riding on the flats. It's consistent and responds well to the app, too, increasing or decreasing speeds with a tap and swipe. Sure, it can be a bit buggy from time to time, but more often than not it's effective. Who knew transformation was this simple? [$590; for preorder at flykly.com]