Jack Neuman of Maynooth, Ont. is looking for a good heavy truck. “We’re going to draw gravel and we’re going to use it to draw logs,” he says. It’s the kind of work that requires robust equipment; something tougher than a traditional highway tractor.

He may not be able to decide between three popular makes, but with 20 years in the logging business he knows exactly what he wants from a Class 8 truck.

Neuman runs down his list of spec’s: a sturdy drive train, a heavy front and rear end, double frame on springs, 18-speed transmission, 60-inch spread and four-way lock-up differential.

But at the top of his list is power. “Approximately 500 horsepower.” He wants the extra power because his truck will be spending half its life in the bush and the other half running the hills of the Ottawa Valley.

Neuman will complement the big engine with an 18-speed transmission and a 4.30 rear gear ratio: “Low enough so we can take off with a big load in the bush, and maybe use it hauling trailers later,” he says.

“There aren’t any scales on those logging roads,” adds George Payton, branch manager of Tandet Kenworth in Peterborough, Ont. Many of his clients are loggers who regularly haul 140,000 lb. loads through the bush. Consequently, they’re looking for powerful machines when they go shopping for a new truck.

“Off-road they’re looking for higher horse, higher torque engines,” he says.

Big power always appears to be at the top of the shopping list among vocational buyers.

Last year, Trevor Lidtke of Palmer Rapids, Ont. bought a Kenworth logging tandem with a 525 Cummins N14. Now he is in the process of spec’ing a new Kenworth tractor that will run a 600-horse Cummins Signature Series engine.

“It provides as much braking power as pulling power,” says Lidtke. “The extra power will enable us to pull a bigger load. Either a five-row trailer or a set or trains. We’re in hilly country, you know.”

Payton cautions that an improperly matched high-performance engine may affect drivetrain warranty. “The important thing with running high horsepower engines is to make sure you’re got the right driveline – clutch, transmission and driveshaft,” he says. “If your engine is producing 2,050 lb-ft of torque, you better have a driveline that can handle that twisting.”

Engine size varies greatly with application. Highway trucks can usually get away with fewer horses under the hood. Often, engine choice is based on personal experience and preference.

Jack Neuman is a fan of Cat engines. George Stein of Schutt, Ont. will only buy a truck with a 470-500 horsepower Detroit in it.

Fred Viger, operations manager of Ariss Haulage in Ajax, Ont. runs a fleet of 80 trucks, mostly Macks and Peterbilts. Half of them are used for hauling sand and gravel while the other half are freight carriers. The highway trucks run 355-380 hp engines while the sand and gravel units are spec’d for a bit more power. “The last truck I bought had a 490 Mack in it and the one before that was a 500 Cat,” says Viger.

Payton thinks that high-performance engines aren’t always necessary. “A 475 Cat with the proper gear ratio will do the same job as a bigger engine,” he says. “Are you going to get passed on the hills? You bet. But some owners are starting to look at fuel economy.”

Most heavy haulers are going with 18-speed transmissions. “That gives them the slow crawl speed they want,” says Payton. “The gear ratio between gears is a lot closer.” Generally speaking, trucks that spend more time on the highway need fewer gears.

George Stein, owner of George Stein Lumber in Schutt, Ont. has been driving trucks for 60 years. He’s come up with his own criteria for highway and bush trucks. For a unit seeing more highway than bush miles, Stein would go with a 13-speed transmission rather than an 18-speed.

This is not too dissimilar from the Ariss fleet, which uses 15-speed Eaton transmissions in its highway trucks and 18-speed Fullers in its construction vehicles.

Rear-end ratios also vary according to use. Stein prefers a 3.56 ratio for his highway trucks and 4.11 for his off-road units, while Ariss goes with 3.70 and 3.90, respectively.

Larry Dombrowski of Barry’s Bay just bought two identical Macks. His selection is interesting because the two units will be used in entirely different ways. One truck will spend all its time on the highway while the other will be in the bush 90 per cent of the time.

Dombrowski wanted sister trucks so they could be interchangeable should one have down time. His choice of 460-hp Mack engines, 18-speed Fuller transmissions and 4.17 rear gears is a compromise between the trucks’ two different lifestyles.

Double frames are standard for most dump and logging trucks. Highway tractors are the exception. Many of those have single frames, while some heavier rigs have double inserts around the fifth wheel.

George Stein, however, doesn’t think that double frames will make a Class 8 chassis any stronger. “All you’ve got is two light frames joined together instead of one strong one,” he says. “And it rusts. You can’t keep it painted.”

Front and rear axle weights are another important consideration. The last time Noel Chesher bought a new truck was almost 15 years ago. But he must have made some good choices because his fleet of seven GM Generals are as active as the day he bought them.

“I’ve definitely got proof that by spec’ing them as heavy as you can has worked because most of those trucks we’re running are 85-6-7s, so they’re 15 years old now, and they’ve done us a good job.”

What the president of Buckhorn Sand and Gravel wanted was double frames with 20,000-lb. front ends and 46,000-lb. rear ends.

The heavier axle weights are suited to the kind of work his company does. His trucks spend about 70 per cent of the time on the highway and about 30 per cent hauling out of quarries and on gravel roads. More recently his company has become involved in hauling limestone blocks for retaining walls and cottage breakwaters.

“There are guys running a picker truck with 20,000 front ends, while highway tractors are more probably 14,600,” says Payton. Rear axle weights also vary from 40-48,000-lb., depending on their use.

Dombrowski’s Macks are hauling logs with 14,300-lb. front ends along with 46,000-lb. rears. Neil Schutt, of Palmer Rapids, Ont. has 16/46 configurations on his 98 International, while William Graff has an 18,000-lb. front end.

But not every vocational application needs the massive rears. Cliff Hall of Cambridge, Ont. has a fleet of Freightliners hauling oversized equipment to and from the U.S., about 99 per cent highway miles. Running stateside makes him more conscious of weight limitations. Also, the cranes, loaders and skidders he pulls are often more awkward than they are heavy.

Thus, Hall’s spec’s reflect the application. The units all have air ride and 12,000-lb. front ends and 40,000-lb. rears are standard.

Chester chose rubber block suspension for his dump units. “It’s a rather hard ride when you’re not loaded, but when you’re loaded it’s a good suspension,” he says. “We’ve put them through some pretty rough paces working around here where there is a lot of rock.”

Nonetheless, Hall estimates that the rubber block suspensions have to be rebuilt every five years or so, leaving him to consider air ride for his next truck.

Neuman, on the other hand, is sticking to what he knows best. “A Hendrickson spring suspension is what I want,” he says. “I don’t like rubber block or air. Rubber block is great but you just don’t have the traction when you’re off road. Air won’t come back quick enough. It’ll lean too far and then you have to wait for it.”

Rear axle spreads offer another crucial variable. Heavy trucks working bush trails are almost always fitted with a 60-inch spread between the tandems. Any longer and the truck would get hung up in ruts and dips in the road. “Sixty is bad enough,” explains Neuman. “With a 72-inch spread I can get a little more weight,” he says. “But it’s not as good traction in the bush and on gravel roads.”

Sand and gravel units, doing road and industrial constru
ction, can accommodate the 72-inch spread. Ariss dump trailers are spec’d to 72 inches for their operation in Southern Ontario. But Norm Chesher finds that the 60-inch displacement makes it easier for his trucks to turn. This is a big factor for his operation in Peterborough County’s rocky terrain, where switchbacks and rock cuts are commonplace.

Certain components are almost givens when spec’ing a new Class 8 truck. An engine or Jake brake is pretty well essential. Also, all the truck owners surveyed said they would probably order a full four-way differential lock-up in their next purchase. “That’s a big advantage in the bush,” says Neuman, where getting stuck is an inconvenience and a loss of revenue.

Payton explains that two switches can activate the four-way lock up systems by Eaton or Meritor. “I can drive on three wheels or four wheels. Three wheels still gives you the ability to maneuver,” he says. “But four wheels means that truck’s coming out there straight ahead.”

The debate over aluminum disc wheels or the traditional radial spoke design is still hotly charged in the logging industry. Larry Dombrowski will not use aluminum hub-piloted disc wheels on his trucks. His previous experience with steel discs left him “very unhappy”.

However, some heavy haulers use aluminum wheels on highway trucks while sticking with spoked wheels for the bush. Others are using aluminum for all applications.

In general, Class 8 trucks are spec’d one above standard for vocational work. Often, high-capacity transmission coolers are added.

William Graff keeps his air lines clean by changing his air dryer once a year. “I change my air dryer every fall and I have trouble-free driving all year,” he says.

Noel Chesher is a strong believer in 250-hour oil changes. “We’ve had one out of seven transmissions go but the motors have never been redone,” pointing proudly to his 300-hp Cummins engines.

“They’re offering mega-miles for some of these new synthetic oils, and they make work in a clean environment,” he says. “But if you’re off the road in the dust and dirt we’re in, we have proven that the 250-hour oil change has given us the longevity we’ve received.” n