The Right Specs
How To Choose The Best Components For The Job
Sponsored as an industry service by Kenworth Truck Company
Produced by Heavy Duty Trucking
By
Deborah Whistler, Editor
Deborah Lockridge, Senior Editor
Tom Berg, Equipment Editor
In trucking, how you specify components counts a great deal - especially the Class 8 market. It's not just the truck's make that allows the vehicle to perform efficiently.
The U.S. trucking industry is diverse and the specs that work for one fleet might not work for another.
Here we will look at what to consider when specifying trucks for particular applications, as well as changes in components that could have a major impact on your next purchasing decision.
Fewer Options
The push by truck builders for alliances with component suppliers has resulted in fewer available options. These affect primarily engines and transmissions, but lists of other types of parts have been trimmed, too. In return for steady, long-term business, a supplier agrees to relatively low prices. The truck builder can pass some of the savings on to buyers - or at least moderate any price increases. Many of those alliances involve engine manufacturers. The engine is the most expensive single component in a truck, and the one that probably develops the most intense emotions among buyers.
Loyal customers can be turned off when favorite engines are dropped from favorite chassis. If an engine is a customer's chief concern, he might have to change truck makes to get his power of choice.
Some truck builders used the changeover to October '02 lower-emissions engines to pare their power options. Freightliner LLC, for example, suspended most Cummins engines, including the ISM and ISX, and made Mercedes-Benz its standard diesel in most makes. The MBE4000 has gained converts, but Cummins is back in Freightliners with some engine models.
Detroit Diesel's Series 60, which successfully survived the switch to Exhaust Gas Recirculation (EGR), remains the best-selling engine in Freightliners. Losses in fuel economy are less than were anticipated. The January '04 version even gained back some economy. Various Caterpillar models are optional in Freightliners and very popular in Sterlings and Western Stars.
And Freightliner has resumed offering Cummins' ISC and ISL, which are non-EGR models by virtue of EPA "credits" earned by DaimlerChrysler for the high-volume, clean-burning Dodge-spec ISB. No EGR means that Sterling, for example, can sell an ISL-powered truck for considerably less than with a Cat C9.
Caterpillar had put most customers on allocation when its non-EGR Clean Power "bridge" diesels gained sudden popularity. Cat's ACERT models have now taken over. They cost many millions to develop and they are priced at the high end of the spectrum. Other engine-related developments at other truck builders:
• International is now emphasizing Cummins engines in its 5000i, 7000, 9000i and other heavy duty models. But Cats remain important, and International now has a more powerful heavy duty midrange-size engine for vocational heavies. International offers only its own diesels in medium-duty truck models.
• Paccar's supplier agreement with Cummins makes those engines standard in most Kenworths and Peterbilts, but the majority of customers still order Cats. Detroit's Series 60, once a popular engine in the Paccar makes, is no longer available; Detroit Diesel is part of the Freightliner organization.
• Volvo dropped Detroit several years ago, and last year quietly axed the Cummins ISC and ISL, which were lightweight options in two vocational truck series. The VHD now comes only with Volvo's own VE D12. That engine is standard in the VN and is gaining popularity, but the optional Cummins ISX is still bought by the majority of VN customers. Volvo has a new 16-liter engine for Europe and other markets, and says the new D16C will eventually be brought to North America. Top rating for the D16C in Europe is 610 hp, so this could be an exciting addition to the Volvo, and perhaps Mack, product lines.
• Mack, Volvo's sister company, has made the ISX the only engine available in its long-nose CL, but only a few hundred are sold each year. Mack still offers the ISL in its Granite vocational truck, but nearly all are sold with Mack's own 12-liter diesels, as is true of all Mack truck models. By 2007, Mack and Volvo will share a new family of modern diesels, though the companies say they'll be tailored for each brand.
Transmissions
What are your vehicles packing for gearboxes these days? Ten-speed models for the heavy tractors and 5- or 6-speeds for medium trucks? If so, you're on a well-traveled road, because those are the most-often spec'ed manual transmissions in the biz, according to the builders. And if you're reluctant to take the plunge to automatic or automated mechanical transmissions - at least in Class 8 trucks and tractors - you're also with the overwhelming majority. About 90% of today's heavy duty vehicles are built with manuals, but more buyers each year are willing to try autotrannies.
Many fleets are now opting for automatics because they give a better chance for every driver to attain good fuel economy. The new EGR engines are much more difficult to keep in the proper power zone for fuel efficiency, and only the most experienced drivers can keep them at their optimum rpms.
Among midrange trucks, automatics have a much stronger following - mainly because many middies tend to run in stop-and-go traffic. In Classes 5 through 7, automatics account for more than half of sales overall, and will grow as more "two-pedal" automated products come to market. In Class 4 and lower, automatics are the rule and few buyers choose the six-speed manuals available in Dodge, Ford and General Motors "heavy duty" pickups. In medium-duty trucks, the 6-speed manual has all but replaced the "5 and 2" - the 5-speed manual with 2-speed rear axle setup that was popular a decade and more ago (just as 5-speeds replaced the "4 and 2" years before). Seven-speed manuals that gained some sales in the '90s have likewise gone out of style in favor of the cheaper and easier-to-drive 6-speed.
6-Speeds Are Neat
A 6-speed has enough ratios for most anything a medium-duty truck will encounter, but a 5-speed might not. A 5's top gear is direct, so the engine might be straining at highway speeds, and if the axle ratio is made faster (numerically lower), startability might not be as good as it should, and the clutch can get beaten up. Even so, the midrange truck market is very price-sensitive and some buyers will pick a 5-speed to save a few hundred bucks.
Those willing to spend the money for a 6th gear sometimes take advantage of 6th's overdrive ratio by mating it with a "slow," numerically high axle ratio; this turns 1st gear into a "creeper" for starting out on steep upgrades or maneuvering in tight quarters. The normal start-out gear then is 2nd. With a faster axle ratio, 1st gear should be used to start out in most circumstances. Of course, a tractor based on a midrange chassis will encounter higher gross weights and will need an 8-, 9- or 10-speed.
Direct Versus Overdrive
Some engineers and fleet managers still debate the argument over a direct-drive top gear versus overdrive. Most heavy transmissions have overdrive or double-overdrive so engines can propel the vehicle at high road speeds and stay in their most economical operating range.
But a direct-drive top gear and a "fast" (numerically low) axle ratio can let the truck achieve the same road speeds, according to proponents. Moreover, overdrive gearing introduces a bit more friction and lube "churning," which saps some energy. Advocates of more efficient direct-drive gearing say this costs money in fuel - usually 1% to 3% more.
Fans of overdrive counter that the loss in efficiency is so small that it cannot be measured in tank mileage except under the most controlled conditions. Everyday traffic congestion and driver habits influence fuel economy far more. And an overdrive transmission sends less torque through the driveline, which can extend shaft life. Since the driveline spins faster, U-joint angles must be as low as possible, but this is easily designed.
And so the arguments continue, but they're seldom loud because both direct and overdrive transmissions do a fine job if they - and all other driveline components - are properly spec'ed.
Heavyweight King
In heavy highway tractors, the 10-speed has replaced the 9 as the most popular model because 10s do a better job of ratio coverage - providing enough "steps" to get the truck up to speed and keep it there. The 10 has also replaced some 8-LLs, 13s and 18s because engines have wide operating ranges and simply don't need more than 10 speeds.
This may be changing, however, as some of the new EGR diesels have narrower operating ranges. Though a high-capacity 18 is commonly chosen for use with high horsepower diesels producing hefty torque, ArvinMeritor has Torq-2 versions of its 10-speeds with 200 lbs.-ft. more capacity in 9th and 10th gears, where an over-the-road tractor spends most of its time. In some applications that 10-speed might suffice. This would save some serious purchasing dollars, with some truck builders charging a premium for an 18-speed.
Eaton also has models that can be rated at an extra 100 lbs.-ft. in the top two gears. But a stout "18" might still be needed with extra strong diesels, which develop as much as 2,050 lbs.-ft. of torque. An 18 is also fun to drive and has high resale value. Spicer recently announced a Pro-Shift 18, and it's already at work in road trains in Australia. It's rated at 2,050 lbs.-ft., like Eaton's Roadranger 18, and engineers are mulling the idea of uprating it to as much as 2,400. But you'd have to special-order the Spicer in trucks made in the U.S. or Canada, because TTC (jointly owned by Dana Corp. and Desc SA de CA of Mexico) lost out in component rationalizations done by truck builders in recent years.
Torque Rules
As you see, torque capacity is as important in choosing a transmission as the number of gears. Capacity has to be high enough to handle the diesel's output, as well as any uprating that an owner may have in mind for the future. Electronic engine controls allow punching up a diesel's output to pull higher loads or, more likely, to give a used truck more resale appeal. Because today's electronics also allow raising horsepower while limiting torque, the original smallish driveline might still be sufficient.
Yet any engine's highest attainable rating should be accounted for when spec'ing the driveline. The engine might produce 1,450 lbs.-ft. for its first owner, but could be boosted to 1,550 or 1,650 later, so the higher output is what the driveline should be built for. This is a cheap option, and should more than pay for itself through higher resale value made possible by the truck's stronger and more desirable engine.
Owner-operators have always favored big power, and so have proprietors of "premium" fleets who want to attract and retain good drivers. Horsepower/torque ratings leveled off somewhat during the recent recession - an almost unnoticed trend that was eclipsed by the serious sales slump. Drivers had to be content just keeping decent jobs. But prosperity has returned, and with it a driver shortage. To compete for drivers, stronger engines may be necessary.
Extended Warranties
Transmissions today last many miles longer than those of yesteryear. Like the diesels they work with, many midrange gearboxes go 400,000 to 500,000 miles, and heavy duty models will go a million miles or more. That's why manufacturers can offer warranties that cover about two-thirds of a transmission's expected life.
Warranties usually are predicated on use of synthetic or semi-synthetic lubricating oils. The builders publish lists of approved lubes, so buyers should be sure that their gearboxes get only those products. Otherwise the warranties may be blown, along with the transmissions.
Owner-Operators
Owner-operators are more likely to walk in off the street and buy a truck off the lot than the fleet customer. Dealers stock the most popular o-o specs - big sleepers, long noses, big engines, comfy interiors, shiny metal trim - which also are found in many of today's fleet trucks. And as the driver market tightens, more and more fleets will be looking to owner-operator-type specs and driver comfort features to aid in driver recruiting and retention.
Some o-o's, however - particularly those who have been in business for a long time - want to spec out a new truck themselves. They know they should steer away from rigs with specs that could cause problems down the road. For instance, some components designed for light weight that end up on many stock trucks might not hold up in some applications. How the truck is put together is far more important than chrome plating and bells and whistles. Then again, fancy items have appeal at resale time, and meanwhile make owner-operators and company drivers happy about what they're driving. As a result, they'll usually be kinder to the truck.
Shopping around for the best deal and best financing package can lower payments and make life easier for truckers and their families. Some dealers sell in enough volume to be able to give an o-o a better deal than a low-volume outlet. Service, too, is important, so look at the dealer's shop and the hours it's open - the longer, the better.
Tanker Trucks
What does it take in a truck to tote a tank body? A stout frame and decently sized running gear, according to people who design and sell such chassis.
Light weight in straight trucks is seldom the consideration it is for tractors that pull tank trailers. A good example is the type of truck that hauls and delivers home heating oil.
The typical fuel-oil body set up for the Northeast is a 2,800-gallon aluminum tank divided into two compartments, plus bottom-loading valves, hose reel and electrical equipment. The body sits on a pair of stiff frame rails and rugged crossmembers that support the loaded tank without flexing. This protects the tank and keeps the truck stable. This is a real advantage for trucks that go off road - like those delivering to farms, quarries and construction job sites - where the fuel storage tank can be across rough ground or on the other side of a shallow ditch.
For a Class 7 truck, which is usually loaded right to its 33,000-pound gross weight rating, this can mean rails as strong as on a Class 8 truck. Some builders have gone to deep-section rails, because eliminating the inverted-L (or other type) liner (or reinforcer) precludes corrosion between the two members - important where salt or chemicals are spread to combat pavement icing - and reduces cost and weight.
Proper weight distribution is important in maximum-load situations, so the wheelbase must be adjusted to suit the cab-to-rear-axle (CA) dimension and body length. Durability is more important than low tare weight, especially because chassis stay in service for 10, 15 or more years.
For safety and liability reasons, a fuel truck's other chassis components must be similarly strong. This includes axles - often a 12,000-pound front and 21,000-pound rear for a Class 7 vehicle - plus beefy suspensions, brakes, wheels, fasteners, tires and brakes. It's better to have too much capacity than just enough, because the weakest link can cause the truck to roll over with messy or fiery results. Either could be disastrously expensive in monetary and human terms.
Air rear suspensions are now available on many medium duty trucks. There's increasing interest in air-ride products because they are more stable in turns. And an air-bag suspension smooths the ride for driver as well as that aluminum body - which can be cracked by shock from rough pavement. Prices for air suspensions have come down, making them even more attractive.
Customers choose air brakes for most Class 7 vehicles and some Class 6s, various builders say. Today's higher-rated hydraulic brakes stop a truck quite well, but linings and other parts for air brakes are cheaper and generally more robust. So lower maintenance costs soon pay for the initial air-brake upcharge of $1,500 or so.
The frame behind the cab must be "clean" so the tank and associated equipment can be easily mounted. This means that fuel and air tanks must be kept clear of the top and upper sides of the rails; if a vertical exhaust stack is used, it should be at the cab's corner, away from its rear. Operators of city delivery trucks prefer the vertical stack to keep fumes away from the driver's face. Rural operators more often use a horizontal frame-mount exhaust.
Power take-offs on tank trucks are usually transmission-mounted, with one on each side of the case. Two PTOs are commonly used to run the pump and hose reel. Some reels can play out the hose, so the driver doesn't have to drag it out and across sidewalks and lawns, as well as wind it back in.
Wiring gets special attention on propane tankers. To keep sparks from igniting fumes, wiring along the frame is covered in conduit and connectors are sealed plastic. Plug-in electrical boxes on all modern chassis are a boon to body makers, who connect lights and controls right to them. Cutting into wiring is no longer required and, in fact, discouraged, because it can seriously disturb intricate circuitry.
Most fuel delivery trucks are purchased with manual transmissions. But Allison automatics are getting more popular, and there's increasing interest in the less costly Eaton Fuller medium duty AutoShift and UltraShift automated mechanical transmissions.
An autotranny eases a driver's workload and helps with recruiting and retention, while also reducing driveline repairs.
Engines of moderate horsepower - often 230 - are all that's required on fuel delivery trucks. This holds down the purchase price and perhaps keeps drivers out of trouble. Because even when the weather's cold, rushing flammable fuel to your customers isn't the best idea.
Construction
Construction trucks vary greatly by locale. Like any industry, construction has its peculiarities and intricacies requiring many types of bodies and equipment.
The truck chassis itself is built according to two main factors: customer preferences and state (and sometimes local) weight laws. The laws mostly affect straight trucks, but heavy haul tractors also must be spec'ed with the laws in mind. Because most construction trucks run locally, federal weight laws are usually not a big factor unless your state has adopted them as its own.
Spec'ing guidelines
• Know what's legal. State laws and sometimes local ordinances limit truck weights by individual axle and by axle group (e.g., a tandem). "Bridge formula" states set minimum distances between axles. This affects frame length, wheelbase, type and placement of auxiliary axles, and other details of how vehicles are configured. So a certain kind of truck - 10-wheeler, tri-axle, quad, super 16, etc. - is useful in one place but useless in another.
However, an upcoming change in state law may allow a new, more productive configuration or, more likely, require one that's more restrictive. Current equipment is usually "grandfathered" for a time in such circumstances, but you don't want to be saddled with something that will eventually be outmoded.
• Learn about special options and programs. Some OEs now can install lift axles on the assembly line, have "integrated" programs with certain body makers, or pre-spec'ed trucks set up precisely for certain applications.
These usually come with special pricing and extended warranties that can save money. Quick delivery programs in many cases can get a freshly built truck into a customer's hands fast.
• Consider innovation. New equipment designs might allow you to haul more, or will reduce maintenance or fuel costs. Sometimes this requires components that are new and relatively untested in your area (steerable lift axles instead of the familiar non-steering type, for instance). Of course, unusual equipment may have poor resale value, so beware of something radical.
• Join an association. Local, regional or state dump truck or ready mix associations lobby for and against legislation that affect their members, and offer knowledge of equipment and operating matters. If it's a good, effective group, it deserves your support and involvement.
Grocery
Operators of grocery trucks often have a standard list of specifications they have developed over time. However, truck technology is changing rapidly, and a spec that was good two years ago might now be obsolete.
Because grocery trucks have to get in and out of some tight spots, maneuverability, visibility and height restrictions are important. Grocery haulers also tend to be extremely safety conscious. Important are mirrors, air bags and collision avoidance systems. The typical grocery truck or tractor is a daycab, but more fleets are opting for sleeper cabs in order to help comply with hours of service rules and not run up big motel bills. Total cost of ownership is important to grocery fleets, so areas such as maintenance, reliability and financing options are key, especially because trade cycles are longer than the average over-the-road fleet. It's not wise to go for the cheapest truck on the block. In the long run, features like aluminum cabs, stainless steel and aluminum componentry that won't corrode, and a good tare weight, end up saving money.
It's not necessarily a price buy for any market, especially those where the trade cycles are extended.
Make sure dealer facilities are set up to support you where they are based and where you deliver. Dealerships should offer parts programs, warranties and maintenance.
P&D Fleets
Pickup and delivery trucks encompass a wide range of vehicles, from a panel van to walk-in vans through medium duty low cabover straight trucks all the way up to Class 7 and 8 trucks with heavy duty components.
And customers are not only buying a cab and chassis, they're also buying a body. Options and combinations abound.
It's important to know the answers to these questions: What are you going to carry in the truck and how will it be packaged and secured? Will cargo be loaded primarily from docks or some other way? How much will be carried in a load? How many stops will the truck make per day? How long do you expect to keep it? Will a lift gate, ramp or special steps and handles help the driver be more efficient and avoid falls? Do you need a translucent roof? How long can the truck or trailer be? Who's going to be driving?
It's common these days for P&D people to have little truck driving experience. The driver may be primarily a route salesman, or he/she may be the one with the least seniority. For these drivers, features like automatic transmissions are important.
Then there's the type of operation. A business with more than 30 stops a day that operates intracity may want to look at a walk-in van. You need to understand the options that are available, from shelves to types of doors to types of seating to lighting, compartments and step heights.
Government/Municipal Trucks
Specifications and price are keys to proper government and municipal fleets. Smart equipment or maintenance managers learn to convince purchasing people on the need to buy something beyond the most basic truck that'll do the job. Premium components can save the agency money in maintenance and repairs, and should be included whenever possible.
Dealers and manufacturers can help with information on how spending more now can pay dividends in the future. Ask if they can provide you with a demo truck and help with the spec writing. Ask to be introduced to factory people and then pick their brains. Make sure sales people are aware of your particular budgetary limits and operating needs.
For instance, dump trucks that double as snow plows carry a lot of weight on their steer axles when plows are mounted. What's the best way to reduce front-end weight on a particular chassis - a smaller but still powerful engine, a shorter hood, aluminum wheels? A sharp sales person will have some good ideas. So will colleagues at association or interagency meetings.
A "muni" truck must also age well. It doesn't get the mileage or hours commercial equipment does because it works in a small area and is often only used for very specific purposes. So most government agencies keep their trucks seven to 15 years, and are concerned about the total cost of the truck over its life.
Find out if manufacturers have special leasing, financing or warranty programs available to municipalities. Some offer optional warranties that cover labor for removal and re-installation of aftermarket equipment during repairs, such as snowplow blades. Everything helps in these days of tight budgets.
