Hauling freight down America's highways is no easy picnic — for either man or machine — but the rough-and-tumble world of field service ratchets up the stress on equipment to a much higher level.

Take the work American Tank Service performs in the oil patch out in Hays, KS, for example. Oil drilling equipment digs deep into the earth — up to 4,000 ft. — and comes up with seawater along with crude, midnight black petroleum.

American Tank's big Mack trucks, such as Granite, CH, RD, and RB models equipped with heavy-duty vacuum systems, take that messy, brackish water from collector tanks at the oil sites, pump it into truck-mounted tanks, and transport it 20 to 30 mi. to special disposal sites where it's pumped back into the ground.

The company's trucks then haul salty water back to the drilling site, where it's pumped into the drill shaft to mix with chemicals for cleaning and to help the drill grind farther into the ground. They also do double duty hauling water to help form cement casings around the drills and crude that can't be used for processing.

It may sound like easy, simple work, but it's as far from that as the Earth is from the moon. Most of the miles American Tank's Mack trucks traverse are bone-jarring, frame-rattling terrain. Smooth, state roads become country roads so ragged and rutted with potholes and rocks they can't be graded. The pathways to the drilling sites are even worse; they're little more than primitive trails gouged out of the ground. More than one plastic dashboard or truck frame have been damaged by the constant vibrations and bouncing due to this terrain.

Factor in seven-day-a-week operation, with trucks handling anywhere from 10 to 12 jobs a day when business is booming, and it's easy to see the kind of punishment the trucks must absorb.

To withstand the pounding, American Tank's Mack models are overbuilt for durability. They max out at 54,000-lb. loaded weight, operate not one but three PTOs and come spec'd with military-style, heavy-duty suspensions.

Engines run a wide gamut of makes and models, cranking out anywhere from 400 to 460 hp., but all come equipped with 18-spd. transmissions as the standard at American Tank. The company's newest Granite Mack models now come spec'd with double frame rails and rugged 18,000- to 20,000-lb. capacity steering axles, plus a 44,000-lb. drive tandem with differential lock and camelback spring suspension, to handle any nasty surprise that might lay in wait in the field.

Tires in particular get a brutal reception in oil patch work. When it gets wet, American Tank must chain them up in order to drive — and sometimes the company must put in a call for a bulldozer to help drag its trucks through the muck.

American Tank generally specs Goodyear Unisteel G177 severe-service tires on steer positions as well as G286 mixed-service tires. It also uses G286A SS wide-base “flotation tires” on the steer-axle position of some of its vehicles. The inflation pressure for all tires is maintained at 100 psi.

The company reports that the deep tread of the G177 works well in the mud because it's strong enough to resist punctures, which are a constant danger due to the off-road conditions. At the drive position, G287 MSA mixed-service tires perform well and last 55,000 to 60,000 mi.

Traction is a major issue out in the field, American Tank reports, so tread life is critical as worn tires quickly lead to flat tires. The rugged terrain does require the company to rotate its tires every 10,000 mi., however, as the high crowns on the rutted country roads make the inner tires on the duals wear faster than the outer tires.

While oilfield service may not be easy work, with the equipment spec'd the right way, it's work that can be done consistently and well with minimal downtime.