Hill-climbing may be a great workout for cyclists, but, well … not everyone has a hilly road nearby. That's why Australian cyclist Michael Freiberg created the AIRhub. Sold as a complete front wheel, its hub incorporates an electromagnetic brake that creates up to 100 watts of resistance. It's sort of like being on an indoor trainer with the resistance turned up, except you're out on the road, where you belong.

The AIRhub generates its own electricity via regenerative braking, so no battery-charging is required.

It's controlled via Bluetooth LE by an iOS/Android app on the user's handlebar-mounted smartphone. That app allows riders to choose between different training modes including one in which the amount of resistance is selected manually; one where the resistance is automatically varied to maintain a given heart rate (a heart rate monitor is required); one that varies resistance to maintain a specific power output (a power meter is required); and, one that simulates an increased coefficient of drag.

It's not just about hill-climbing, however. The device could also be used to hold oneself back when riding with a slower partner, to pack more of a workout into short-distance rides such as commutes, or to keep the speed at a safe level while still getting a high-intensity ride on cycling paths.

The hub itself has a carbon fiber and aluminum housing, and tips the scales at 1.5 kg (3.3 lb). It's incorporated into an aluminum-rimmed 700C wheel, which should fit most road bikes.

If you're interested in getting one, be prepared to pay AUD$1,950 – or about US$1,496.

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