[mhs4771]

We have one similar to what Ozz posted. Sold under various names, Tire Minder, Tire Traker, and one or two more.
It works but not the greatest in the world. If we've been running for several hours in pretty warm weather the tires do heat up, no big deal, but we'll stop for Fuel or whatever and the tires will start to cool, so the system does what it's suppose too, gives an alarm for a leaking tire, worrys you the first couple of times it does that. But the problem is it won't reset for 15 or 20 minutes so now if you really did develop a leak you would probably ignore it. Just my experience with Tire Traker. Will probably change to a better system sometime in the future.