Driving the MX

Steve Sturgess • Executive Editor

Lined up for us to drive at the Dutch proving ground were a selection of XF and CF models and a single LF. I had recently driven the smallest DAF, both as a Kenworth and a Peterbilt Class 7, and found it just a jewel of a truck: easy to drive with a synchronized six-speed, precise, light steering, great visibility, excellent ride and so, so quiet.

Many of those virtues were found on the CF and XF - but on a bigger scale.

The CF was extremely nice to drive, with plenty of room for the driver, even if tight in the narrow sleeper. It was an extremely modern feeling, with a nice automotive style dash and loads of burlwood accents. The ride was smooth and the driving an exercise in quiet comfort. CFs had both the astoundingly good 12-speed AS Tronic automated transmission and also the air-assisted manual ZF 16-speed.

The MX engine worked particularly well with the AS Tronic and, despite being loaded to 40 tonne (88,000 pounds) the CFs got up to speed nicely with no fuss.

It was the big XF, though, that I really wanted to experience. It has the huge boxy cab that is mounted on four suspension points that are very softly sprung. There are four steps up and the cab floor is nearly five feet from the ground. It rocks as you climb aboard. As you nudge the transmission into gear and take off, the cab settles back on its suspension. As throttle eased and the transmission shifted, the cab would rock forward and then back again as the clutch engaged and the electronics poured on the coals.

While this takes a little getting used to, the ride that the truck suspension and cab provide are very easy to get to like. With a test driver beside me, I was instructed to get off the billiard-table smooth lanes of the track and attack some of the deliberately rough sections of the durability course. The XF truly amazed with its ability not only to absorb outrageous potholes and surface changes, but to do so without my losing any measure of control. Wheels stayed on the ground, the steering retained feel without any kick back. It was just a magic-carpet ride despite the awful road conditions.

We were supposed to be experiencing the MX engine, but the only sensation to come through was of comparatively effortless propulsion. The biggest horsepower MX has a torque curve flat at 1,850 pounds-feet from 1,000 to 1,400 rpm. Then as the torque starts to fall, the horsepower has risen to 510 horsepower and stays flat right out to rated speed at 1,900 rpm. The effortless gaining of speed is the only sensation. You absolutely cannot hear what is going on, so quiet is the engine and so good the cab insulation.

Peterbilt and Kenworth will offer the MX 12.9 liter alongside Caterpillar C13- and C15-liter as well as Cummins 12-, 15- and 16-liter ISX engines. It will provide customers with an additional choice of power, said Dave Giroux, Peterbilt's director of communications during the visit to Eindhoven.