.
Remember White Crow Technologies? The company’s patented Dynamic Traction Control concept consists of two major parts that allow the rider to pressurise or de-pressurise their tyres at the flip of a bar-mounted lever. The first component is a hub-mounted pump, which uses the rotation of the wheel to de-pressurise the tyre. The second is a (Schwalbe Procore-like) inner tyre chamber. The reason that the pump is used to de-pressurise (effectively suck air out of) the tyre is to take advantage of a higher-pressure tyre’s low rolling resistance when additional energy is needed to operate the pump and to make re-inflation quick and easy, especially when one goes too low. Using an inner chamber provides a relatively large, low-pressure storage space, which means that less energy is required to pump and the system needs not be engineered with high-pressure fittings or tubing. Because no air is drawn from the atmosphere, there’s also little chance of filling one’s tyres with water on wet days.
..
The company was back in Las Vegas this year with a booth displaying a closer-to-production of their pump-stroke-hub and a rather polished looking lever.  Company representatives were reluctant to speak too much about the system as it nears production- but suffice it to say the the concept remains largely the same.
...
The one Iditarod veteran we mentioned the hub to was extremely excited about the idea and hustled over to take a look- so White Crow may well find itself a hungry market.  Maybe next year we’ll have production pricing and availability.