4-Step Process Learn How to Spec Trucks Like the Pros

Inexperienced fleet managers who find themselves in this situation typically rely on manufacturer representatives, their fleet management company, or truck dealers to assist them. These truck specialists can be a great help in calculating weight carrying capacities, powertrain requirements, drive axle ratios, body lengths, and truck configurations that are best suited to meet your fleet application. However, unless you, as the fleet manager, understand the fundamentals of truck spec’ing, you cannot properly manage the specification process. What follows is a four-step truck spec’ing tutorial designed to help you understand the fundamentals of the specification process and to learn how to ask the right questions of your drivers and suppliers. The first step to correctly specing a truck is to meet with the drivers or technicians who will be using the vehicle. "By understanding their day-to-day application, you will be able to build a truck that meets their needs," says Dan Karst, truck specification engineer for PHH Vehicle Management Services in Hunt Valley, MD. "Sometimes there is a misconception by the fleet manager as to what is actually needed in the field. The best way to avoid this is by talking with the end-users." In particular, the fleet manager needs to understand what type of service the truck is expected to perform, says Bill Byron, manager of truck purchasing for Donlen Corporation in Northbrook, IL. "He or she will need to discuss the truck’s actual in-field application and usage with either the regional or district managers, depending upon the size of the fleet and the various levels of purchasing approval required," said Byron. "Most smaller, more centralized fleets have facility managers or warehouse foremen, who know what does and does not work for them." Sometimes this information can be gathered over the phone; however, for more complicated applications it may require a site visit. "Most of the questions that a fleet manager has will be answered during a site visit," says Karst. The key objective to these discussions is to match the truck with the fleet application, says Tony Cordato, director of truck and equipment engineering for US Fleet Leasing in Carrollton, TX. When meeting with your end-users, Cordato suggests asking them questions about their current vehicles. For example:

• Is the powertrain right for their application?
• Is the gross vehicle weight adequate for the payload carried?
• Is there enough gross combination weight rating (GCWR), if the vehicle is used to tow a trailer?

Agreeing with this approach is Terry McMahon, truck application engineer for GE Capital Fleet Services in Eden Prairie, MN. "Look at the existing truck and investigate the maintenance records. What type of problems has this truck had, if any? This will help you determine if the current vehicle has been under-spec’d. If it has, then take the necessary steps to correct it. I find that the majority of trucks that have problems are under-powered and over-loaded, which results in those dirty words – downtime," says McMahon. Scrutinize your maintenance records to see what mileage, and at what time intervals, your present trucks have needed major servicing such as a brake re-line, new or recapped tires, and engine work. Talk to the employees who are using your trucks. They may have problems with loading height, cab access, lack of bins, difficulty when backing, or insufficient tool storage. Ask them about passenger requirements, whether there is going to be a high idling requirement, how the payload will be distributed, whether the vehicle will be fully loaded, or whether it will be operating with a diminishing load, and how they load and off-load cargo, says Wayne Reynolds, truck specialist, corporate fleet leasing for Lease Plan in Atlanta, GA. Consideration should also be given to whether a liftgate, pull-out ramp or pull-out compartments should be chosen for the truck body, says Bob Shipp, truck sales manager for ARI in Mt. Laurel, NJ. Another consideration that affects cargo delivery is the type and number of doors. "To increase driver productivity, you may want to consider side doors, and the type of rack and bins configuration," says Shipp. Swinging rear doors may be less expensive to maintain, but they may pose a problem when space is limited for loading and unloading. "It is important to design a truck that will accommodate your operational requirements rather than trying to make your operation conform to the truck," advises Mike Corchin, director of truck operations for Wheels Inc. in Des Plaines, IL. After compiling the input you have gathered from the field, you must next review budgetary considerations, says Byron. One factor that can sway the decision on which chassis to acquire is the manufacturer’s incentive program, adds Karst. "The type of truck your field personnel would like may not always fit into the annual budget," says Byron. "Additionally, some driver-requested options such as a cassette radio or power windows need to be scrutinized. Although they may provide driver convenience, they may not return their dollar value at resale." If you are not careful, it is easy to over-spec or under-spec a vehicle, with each presenting its own unique set of problems. "Over-spec’ing a truck increases the capitalized cost of the vehicle, while under-spec’ing increases maintenance cost," said Shipp. "In addition, an overloaded vehicle puts your company at risk of a lawsuit if it is involved in an accident." According to Patrick Gallagher, vice president of sales for AMI Leasing in Worcester, MA, "The most common mistakes made in truck spec’ing are that engines are too small or the body is not high enough." “After standard specs are established, they should be reviewed each year with the maintenance provider to make changes to the components if necessary," said Shipp. "Specifications and maintenance records should be reviewed yearly." Payload is probably the most critical aspect of truck spec’ing, said Russ Cass, fleet truck manager for Piemonte National Fleet in Melrose Park, IL. "The real estate industry has a saying, ‘Location, location, location.’ The truck world should have the motto, ‘payload, payload, payload.’" There are three main components of payload, points out Cass. "The first component is payload weight. How much weight will the truck need to carry in its daily work load? You need to figure the maximum need here, not an average. The vehicle must be able to do the job every day with the maximum load at any given time. Payload weight will also help determine if the cargo can be loaded and unloaded by hand or whether you will need a power liftgate or some other type of assist to get it up in the body or bed," said Cass. "The second component is payload size. How big is the load? What is the necessary cubic feet of space to hold the material that needs to be carried? This will help determine the actual size of the cargo area. Will a pickup box handle it or will you need a 26-foot van body to carry everything that must be hauled? "The third component is the actual type of payload. Are you going to carry loose gravel, pallets of frozen food or boxes of Beanie Babies? This will decide the type of truck and body combination you need to choose," said Cass. One practical tip on how to determine actual payload is offered by McMahon at GE Capital. "My suggestion is to have the truck loaded as it would be in a normal work day and have the truck weighed. Also, have the front axle and rear axle weighed. This will tell you if you are over-loading the whole truck or just one of the axles. Maintenance records should back this up." By determining the fleet application, you will determine the payload, said Karst of PHH. Byron agrees, "The single most important factor in selecting a truck is determining the payload needed to perform a particular operation." Overextending a truck’s payload capacity beyond the chassis’ weight specifications is a good way to shorten the truck’s service life. "Overloaded trucks will cause a variety of problems such as premature tire wear, lost miles per gallon, and downtime due to engine or transmission repair," says Byron. In addition, overloading may put you in trouble with the law. "Overloading results in fines from the police and possible impoundment of the vehicle by the authorities," adds Shipp of ARI. "Also, there is significant company exposure to lawsuits should an accident occur." According to Corchin at Wheels, the most common mistake made in spec’ing a truck involves payload determination. "Making uneducated guesses about issues such as payload weight and operation can have disastrous effects on the operation of the vehicle and can certainly jeopardize the safety of the driver as well as cause premature component failure and shorter truck life." Cargo rating is one of the prime components of the GVWR, and the weight, type, and length of the payload are determining factors of chassis length and body selection. Cargo rating is the ratio of cargo weight to cargo volume that is needed to properly size the payload. "The rule of thumb in determining cargo rating for a medium-duty straight truck is that the cargo ratio on the front axle should not exceed 15 percent of the payload and should not be less than 10 percent of the payload," says McMahon. He cites several reasons for this:

1. Overloading the front axle or rear axle will cause excessive wear and tear on components such as tires and suspension, which will cause increased maintenance and downtime.
2. Less than 10 percent on the front axle can cause some loss of steerability and also excessive wear on tires from flat spotting.
3. Overloading makes a vehicle unsafe to drive and more prone to be involved in an accident.

Load density calculation relates to the payload, which is simply the combined weight of the cargo, occupants, and fuel. In addition, there are "special requirements," such as auxiliary equipment, which may require special truck components or heavier than normal specifications. For instance, adding a generator or a hydraulic crane might mean modifications to suspension and axle ratings. "You need to make sure that the truck can carry not only the payload but also any additional equipment you put on the truck," said Karst. The fleet manager needs to add the body and equipment weight to that of any tools or other material that could be stored or transported by the chassis. "Let’s consider a hypothetical situation of adding a crane to a chassis," says Byron. "Let’s say the maximum available payload listed by the manufacturer for a particular chassis is 3,000 lbs. After selecting the desired engine, transmission, and other options, the actual payload results in 2,700 lbs. The utility body with empty compartmentation weighs 1,500 lbs. Tools and miscellaneous equipment weigh 800 lbs. The fleet manager must now realize that the crane’s weight cannot exceed 400 lbs. or the vehicle would be exceeding the manufacturer’s payload maximums," explains Byron. "All manufacturers build in buffers regarding payload, but adding what the chassis needs to carry and subtracting that figure from the listed maximum payload is still the safest way to avoid overloading. Frankly, this simple formula is age old, but is often overlooked." When reviewing the criteria for choosing a truck, one of the most important aspects is the gross vehicle weight rating or GVWR. This rating reflects the maximum GVW a particular truck is certified to carry. This rating consists of two weight factors: the empty vehicle (curb weight), and the payload it will carry (the contents to be hauled, the passengers/driver, and fuel). To determine the correct size of a vehicle for the intended payload often requires a non-scientific judgment call: namely, how much over-capacity to build into the payload capacity of the vehicle when spec’ing its requirements. Spec’ing the truck to the minimum necessary payload rating (by basing it on an average load, or looking at only today’s business needs instead of trying to anticipate future needs) means that the vehicle will be operating at peak capacity most of the time, which may compromise safety and the length of its service life. Using average payload for specs means that the vehicle will sometimes be overloaded – and that means excessive wear and tear, higher maintenance costs, and poor fuel economy. At the same time, too much payload capacity is wasted capacity that should be avoided. "One of the most common mistakes made by fleet managers is not understanding the importance of allowing reserve GVW when spec’ing a truck," said Cordato of USFL. "Having the correct amount of reserve will allow the truck to perform the intended job over a longer period of time, with less downtime." According to Cordato, some items to consider when determining how much reserve GVWR is necessary include the wheelbase, axle rating, the type of body, and the type of application. "Generally speaking, there should be approximately 20 percent reserve GVWR," said Cordato. Corchin at Wheels agrees. "I would suggest that a 15- to 20-percent payload cushion be used as a rule of thumb. For example, for a 5,000-lb. maximum payload estimate, I would spec a vehicle that could carry between 5,750 to 6,000 lbs." GVWR alone, however, does not tell what class or size of truck is needed. How the cargo is distributed is also extremely important, and partially determines gross axle weight rating (GAWR), which identifies the maximum load-bearing limit of a complete axle and suspension system, made up of wheels, tires, and springs, but not shocks. Essentially, GVWR is determined by the lowest rating of a truck’s load-carrying components, which include the frame, springs or suspension, axles, and tires. For the most part, shock absorbers are not included in an axle’s weight rating, since they are not designed to carry weight. The weakest link among these components, usually tires, determines the GVWR rating. "A vehicle can be under the GVW, but can still be overloaded on one of the axles," said Shipp. "Drivers will fill space if it is available." The GVWR and GAWR cannot be exceeded without risking some serious problems, such as steering and handling problems, excess wear, and reduced vehicle life. The converse is true as well; it makes no sense to over-spec a truck, because the vehicle will inevitably incur higher operating costs because the truck is under-utilized, causing a fleet to pay for more capacity than it needs. "Also, local laws may require special options to drive on certain roads," said Shipp of ARI. "Certain vehicles may fall under D.O.T. rules that must be taken into consideration such as driver logs, CDL license, and safety options." Where a truck operates can dictate the truck style. For example, fleet operations in metropolitan areas can dictate whether a one-ton covered van or a cab/chassis with added body are required. Similarly, tight operating conditions may dictate the type of truck that is recommended. "Extreme weather conditions will also determine necessary options," said Cass. "What weather will the truck operate in. The vehicle may need cold weather aids such as an engine block heater or maybe extreme heat equipment such as extra engine cooling and oil coolers." Once the size of the chassis has been determined, it’s time to think about powertrains. The powertrain is made up of the engine, transmission, driveline, rear axle, wheels, and tires. The first thing to consider when selecting a powertrain is the operating conditions and performance criteria, said Reynolds of Lease Plan. This involves nine factors:

1. How will the truck be used?
2. Typical GVW or GCW.
3. Annual miles.
4. Expected operating surfaces.
5. Desired cruising speed.
6. Desired startability.
7. Desired high gear gradeability and cruising speed.
8. Vehicle configuration, such as number of drive axles and tires.
9. Operating altitudes and temperature.

The anticipated annual mileage will help determine whether to spec a gasoline or diesel engine, said Shipp. The speed you expect your truck to travel is also an important consideration. Will it be stop-and-go city driving not exceeding 55 mph or will it be at highway speeds? "Knowing this will help you determine what engine, transmission, and axle ratio you will need," said McMahon of GE Capital. A truck’s engine horsepower requirement is determined by the desired road speed at which the load should travel. This establishes the guidelines to select the right engine and transmission, which is important for minimizing overall operating costs. The proper engine and transmission selection must achieve a balance between operating economy and vehicle performance requirements. "Today, manufacturer ordering guides, along with available spec programs, have taken much of the guesswork out of selecting powertrain components," said Byron. "In most light-duty applications, once a drive has been determined (2WD or 4WD), the manufacturer’s order guide will usually offer one standard four- or six-cylinder engine and possibly optional six- or eight-cylinder engine, sometimes including a diesel." By determining the speed at which a load should be moved, another fundamental guideline, final axle ratio, is determined. Rear axle ratio selection is based on two major factors: the desired road speed and the governed engine speed. This can be used to calculate the best ratio to get a vehicle to the required maximum speed. How fast and under what conditions the load must be moved will also have a direct bearing on the final drive ratio requirements. The final drive ratio is simply the number of revolutions the drive shaft makes compared to the turns of the drive wheels. A 4.10:1 ratio means that the drive shaft turns 4.10 times for every one revolution of the drive wheels. Higher ratios usually mean better startability, gradeability, and towing capability, but at the expense of a lower top speed. Higher ratios make sense for fully-loaded trucks operating in congested urban conditions, or those which must negotiate hilly or steep road conditions. Typically, when road speed rises, there is a corresponding reduction of torque, which requires a lower axle ratio. An axle ratio selection chart indicating various governed engine speeds can be used to determine the correct rear axle ratio. "You must consider three things when determining what axle ratio to use," said McMahon. Those are:

1. What is the steepest grade your truck will go up?
2. How fast do you want to go?
3. Will this truck be operating in on- or off-road applications?

Off-road operating requirements might call for a different suspension, or different transmission-rear axle ratio combinations. "Also, determine whether there will be an increasing or decreasing load throughout the work day? Will the engine/transmission/axle ratio support the payload, allow for trailering if needed, and be compatible with strict federal emission requirements?" said Byron of Donlen. There are, of course, other factors in powertrain selection such as engine rpm, torque efficiency, engine governors, number of transmission speeds, and transmission ratios; but the fundamental requirement – speed – establishes the guideline from which these specifications are developed. Transmission choices vary from four-, five-, or six-speed manuals to five-speed overdrive automatics. "A fleet’s required vehicle delivery time and the production time of the manufacturer may not be acceptable," said Shipp of ARI. "For example, some manufacturers have better allocation on automatic transmissions than others. Some are three months, while others could be out to one year or more. There are other transmissions available that could be selected to shorten the production time, or the selection of a mechanical automatic over an electronic automatic transmission will shorten lead time." The terrain a vehicle will travel will help determine the type of transmission. "If the truck will be doing highway miles, then you will want to match it with a lower rear axle ratio and a transmission with as many forward gears as possible to achieve maximum fuel economy," said Karst. "If you will be driving in hilly country, you will want a higher rear axle ratio to provide more torque." One factor prompting fleets to specify automatic transmission is that there are not as many drivers today who can operate a manual transmission as in the past, said Karst. Agreeing with this is Rey- nolds of Lease Plan. "Recently, I find that many fleets are opting for automatic transmissions, especially if initial cost and availability are not overriding issues," said Reynolds. Cass of Piemonte National Fleet offers this perspective: "Manual transmissions cost less to purchase and repair, but in the long run, automatics can be easier to operate and don’t have clutches to replace." If your application requires a power take-off, it could dictate an engine power modification. A power take-off is a device mounted on the side of the transmission or transfer case or off the front of the crankshaft and is used to transmit engine power to auxiliary equipment such as a winch.

How to Purchase a Service Body That’s Right for Your Chassis

It is important to consider the truck body selection when making decisions about the chassis. A delivery truck needs a body and chassis that work together properly as a unit. It is a good idea to arrange a meeting with the dealer, the truck-body upfitter, and your company, so that all the parties can discuss specification details. Body upfitters sell to existing truck owners as well as to dealers. A big advantage in purchasing both together is financing both body and chassis simultaneously – either through purchase or a leasing arrangement. Some body installers and upfitters have drop-shipment arrangements with manufacturers that permit customers to have a body installed before the truck is received by the selling dealer. Talk to your truck dealer or fleet management company to see what they can do to assist your financing. Another factor to consider when selecting a chassis is the cab-to-axle dimension. This dimension is very important when you add a second body such as a service body or any additional equipment on a chassis. The cab-to-axle, or CA, is the dimension taken from the back of the cab to the center of the rear axle. "The cab-to-axle dimension of the chassis will determine the length of the box you are going to be putting on the chassis," said Karst. Some problem areas that fleet managers sometimes encounter in spec’ing a service body are:

"When upfitting you need to ensure that your vehicle stays in compliance with FMVSS regulations and motor company safety requirements," adds Karst. Should you remove the body before remarketing the used truck? Opinions vary, but a rule of thumb is to leave the add-ons with the truck, especially if extensive additions were made. The reason is that the chassis is set up for the body originally installed, and even though it may outwardly appear similar to other chassis, its usages are limited by the chassis specs. Some users still remount old bodies on new chassis, but with truck chassis lasting longer these days there is less reason to do so than in the past.