Phillip writes: “This is a really cool ‘why didn’t I think of that?’ tool. It’s available from Summit Racing. Looks like it would be useful for many applications besides racing.”
These are used most often by drag racers, who manipulate tire pressure in miniscule amounts to control traction. Of course, since they don’t turn — at least not on purpose — they definitely want both tires with equal pressure. These are used by road racers from time to time as well, but not by circle track guys.
Percy’s offers a couple of different versions ranging from a “basic” model (sans tire gauge) to a 60 psi version. Pricing at Summit starts at $30 and goes up to $60. As you can see from the street pricing link below, they’re available from a crapton of vendors, but they’re all about the same price.
As far as other applications, I’m not sure. The idea hear is to set the pressure of two tires at once, which is really a speed thing — not something you’d use a lot in your driveway.
What do you think? Can you see other applications?