Like a lot of other factors involved in mountain biking, setting the air pressure of the tires is a matter of compromise. Keep them too soft, and you can’t go as fast as you’d like on smooth stretches of the trail – keep them too hard, and they’ll just bounce off of roots and rocks instead of gripping them. As it stands, most bikers go for a “Jack of all trades, master of none” setting, that allows for some traction and some speed. The folks at ADAPTRAC, however, apparently think that such a compromise shouldn’t have to be made. Their new system allows riders to inflate or deflate their tires as conditions dictate, while they’re riding.
The ADAPTRAC system works as follows ...
Toggle switches on a handlebar-mounted control unit allow riders to add or remove air from their front or rear tires. That unit can also be mounted on the stem or down tube.
If more air is requested, it is released from a down tube-mounted rechargeable compressed air tank – these tanks are available in a variety of sizes. An attached regulator brings the pressure of the stored air down to a system-friendly 175 psi, as it leaves the tank.
That air travels through one of two frame-mounted hoses, to either the front or rear ADAPTRAC wheel hub. The hose/hub couplings incorporate “special, extremely low friction rotary seals,” to keep air from leaking out while allowing the wheel to spin freely. From the hub, the air goes through another hose, that leads out to the tire’s valve stem.
When softer tires are needed, presumably air is just released from them into the atmosphere. The current air pressure of the tires is displayed on two bar-mounted analogue gauges.
ADAPTRAC's Paul Skilbeck tells us that the product is still in the late prototype stage, and that a price will be announced shortly after the system is presented this week at the Sea Otter Classic Expo in Monterey, California. He added that the total system weight is about 690 grams (1.5 lbs) with an empty 9-ounce (266 ml) CO2 tank – keep in mind that the custom hubs would replace those presently on the bike.
Source: ADAPTRAC
It must be real nice to have the money to throw away a good bike because it does not have all the latest bells and whistles. for the rest of us an add on system is the best we can hope for. I do agree that a shock-absorber (Spring damper) compressor would be a nice touch.
Designing the pump to pump to a higher than maximum tank pressure and venting into the tank through a tiny hole would minimize the ride changing with tank pressure, and so would running hydraulic fluid through a motor at significantly lower pressure than the ride control valve contains.
The people who'd really benefit from such a system are the people too stupid to realise they need to pump their tyres up and have the pressure automatically adjusted.
...I do love the bike tech articles - keep em coming!
1.5 pounds for the equipment .6 pounds for the liquid CO2 so 2.1 pounds minus the weight of the hubs already on the bike.
Having hard tires across firm terrain will pay for that penalty within a couple of miles.
i would love this on my motocross bikes as well, adjusting tire pressure for the terrain is very handy. Super soft in super soft beach sand and median for dirt