Twin-steer front axle trucks are rather common in Europe, as Johannes Dutch has shown us here on numerous occasions. After a discussion regarding their existence (or not) in the US, I looked up and found that Western Star, a division of Daimler, does make and sell one in the US. And not more than a couple of months later, I ran across this one parked by the Embers Supper Club, a popular C&W joint. So let’s take this behemoth in.
Generally, the axle loading restrictions have kept twin steer trucks from being practical solution in the US. Tag axles, which can be lowered under heavy loads and can typically steer passively, are more commonly found between the front and rear axles in those states where lower axle loading make them necessary for maximum overall loads. But these are two full-sized, full-time front axles, with interconnected steering gear.
Here’s the main (mechanical) steering gear, working on both axles.
Another shot of that. According to Western Star’s web site, these trucks have “dual main gears with dual ram assist”.
This is the other side, and that looks like the hydraulic ram for the front axle, in red.
And presumably the one for the rear front axle.
In back, the front two driven axles are on a Hendrickson Walking Beam bogie, a very rugged unit that relies on the the central pivot to allow the two axles to move up and down, but there’s no real springing per se, except for the rubber mounting blocks.
Here’s a better look at that. Very tough, but not nearly as soft riding as air suspension, which has become so common on big trucks.
But there’s the typical air suspension units under the last axle, which is not powered, and can possibly be raised. Maybe not on this unit, as it certainly wasn’t carrying a load.
A commercial plate, obviously.
I might have taken a closer look at the business end of this rig, to get an idea of how it attaches to the object it is intended to retrieve and tow. But I didn’t.
Under the hood is a modern four-stroke Detroit Diesel, which Daimler bought some years ago from Penske, who bought it from GM. There’s a variety of outputs, from the 400 to 600 hp available.
An impressive sight. And I hope to never have to need it.