Off-road vehicles have had tire auto-inflation systems for years now, because a soft tire can provide a better grip on a rocky surface. And the same functionality can also benefit mountain bikes too, which led to the development of the Adaptrac tire inflation system for bikes.
Bikers tackling rough terrain are already able to adjust the tire pressure in their wheels, it just requires them to stop and get off their rides to do so. And that's no fun. So the Adaptrac system uses a special set of front and back hubs with a valve connected to a CO2 tank mounted on the frame.
A set of controls mounted on the handlebars lets the rider increase the pressure in either tire, while a regulator valve sitting between the tank and wheels ensures they don't just instantly inflate to the point of popping. In fact, a pair of analog gauges provides a constant reading of the actual pressure in each tire so you don't over-inflate them. So in theory, a mountain biker could tweak the feel of their ride without ever having to break out a tire pump, or even stop pedaling.
Of course the whole system is completely dependent on how well the hubs are engineered. A set of rotary seals supposedly ensures there's no air leakage even while the tire is spinning, but that's something you don't want to fail when you've ridden several hours into the backcountry. As for pricing and availability, that will be announced sometime in the next couple of weeks after the design on the last prototype is finalized. [Adaptrac via Gizmag]