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General Considerations
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- Body Type
- Van, Flat Bed, Stake, Dump
- Body Length
- Defines the Wheelbase / Cab-to-Axle (CA) dimensions
- Payload (the commodity and how much it weighs)
- Defines the Gross Vehicle Weight Rating (GVWR): body and equipment weight plus the weight of the commodity and the cab/chassis weight. Also defines the Model Series of the Truck; e.g., C5500, C6500, C7500, T6500.
- Operating Conditions
- Defines the requirements for engine, transmission and gear ratio selections
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Will the operator have a Commercial Driver License (CDL)? If not, the truck must have a GVWR of 26,000 lbs or less. Note: In some states, a truck equipped with Air Brakes (JE4) cannot be classified as a "non-CDL" truck even with a GVWR of 26,000lbs or less. Always check local requirements.
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Applied Example
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- Non-CDL Truck
- 10,000lb Payload
- 20-ft Van body with a lift gate
- Predominately expressway driving in Central Ohio delivery goods from a warehouse in Dayton to Toledo, Ashland and Cincinnati-area retail outlets
- Loading at warehouse is from a loading dock
- Deliveries are typically at ground level
- No Trailer
- Approximately 40,000-miles per year
- Multiple drivers with diverse experience levels
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- Available recommended wheelbase/CAs for a 20-ft Van body are 212in/144in, 224in/156in or 236in/156in. Due to the specification of a lift gate and the additional weight it adds to the rear of the frame, the first choice would be to use the 236in/156in length. Local area practices and body company recommendations should always be considered.
- Maximum GVWR: 26,000lbs due to user's requirement for non-CDL vehicle
- Gross Combination Weight Rating (GCWR) not a consideration due there being no trailer
- Speed Limit in Ohio for trucks is 65 MPH - the terrain is typically flat along the route, dictating an engine with a lower horsepower/torque rating, which has the potential for greater durability and better fuel efficiency
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- Model C6C042 - Right Spec D6AVN
- Upgrade engine to 230HP/660 lb-ft Isuzu 6HK-TC diesel engine
- Allison 2200 HS/RDS Automatic Transmission
- 10,000lb capacity front axle and tapered-leaf front suspension with standard stabilizer bar
- 19,000lb capacity rear axle
- Rear Suspension - Choice should comprehend commodity to be hauled
- Fragile Load - use 19,000lb capacity tapered-leaf suspension with required rear stabilizer bar and shock absorbers or a 19,000lb capacity air ride suspension
- Standard Load - use 21,000lb capacity multi leaf suspension
- Rear Axle Ratio - 5.29:1 - provides excellent fuel economy and more than 24% "start-ability" - at 65 MPH, the engine will be turning approximately 1800 RPM, allowing the Allison Automatic to downshift if a grade is encountered, ensuring little road speed loss.
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Engine
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- Load: Heavy loads require higher horsepower/torque engines.
- Terrain: Hilly or mountainous terrain requires higher horsepower/torque engines.
- Annual Mileage covered: High annual mileage (greater than 25,000 miles) dictates diesel power.
- Customer Expectations: Many drivers expect the truck to drive up grades similar to a passenger car or light truck.
- Stationary Power Take-Off (PTO) applications: PTO operations typically require an electronic hand throttle, requiring a PTO drive gear in the automatic or manual transmission.
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Transmission
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- Primary factor is driver capability.
- An Allison Automatic Transmission is indicated unless driver skill set includes operating a manual transmission - with special attention to clutch operation. Note: If hydraulic brakes are specified, an available automatic with a PARK position is an excellent choice.
- Synchronized 5- and 6-speed manual transmissions are suitable for many applications, if the drivers' skill sets are adequate.
- Multi-speed Road Ranger transmissions are suitable for heavy applications such as single- or tandem-axle dump trucks or pulling a heavy trailer, but require excellent driver skills.
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Front axle/suspension
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- City operations with potential for increased "curb-banging" dictate the use of higher capacity front axles to improve durability.
- Tapered leaf front suspensions are appropriate for vans, flat bed / stake, and delivery type vehicles.
- Multi-leaf suspensions are a must for dump trucks and snow plows.
- A front stabilizer bar / shock absorber is always a good choice.
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Rear axle/suspension
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- For heavy and/or high center of gravity loads, multi-leaf rear suspensions are indicated.
- Rear stabilizer bars / shock absorbers are always a good choice.
- For transport of fragile merchandise (such as electronics or furniture), use tapered leaf suspensions with available stabilizer bars and shock absorbers.
- Air suspensions, though more expensive, are an excellent choice where a soft ride is paramount.
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Chassis
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- Longer wheelbases may require higher capacity frame rails and reinforcements to maintain front axle capacity ratings.
- Dump applications dictate either higher capacity frame rails, reinforcements, or both.
- Bucket truck applications typically convey increased loads into the frame rails. Note: Consult truck body and equipment supplier recommendations for minimum requirements and follow or exceed their guidelines.
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Cab
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- Cab options primarily consist of comfort and convenience items: air ride suspension seats, 2-person passenger seating, air conditioning, power windows and locks, remote keyless entry, tilt wheel, cruise control, etc.
- Consider your drivers' needs and choose accordingly.
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Brakes
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- Hydraulic brakes are typically specified for lower weight class applications (26,000lbs and under).
- Air brakes are utilized in higher capacity applications and severe stop-and-go operations, such as refuse service.
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Fuel Tank
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- On C4500 and C5500, fuel tanks are located inside the frame rails amidships and also behind the rear axle.
- If secondary bodies or an under-body hoist require "real estate" for attachment/operation, be certain the fuel tanks do not interfere.
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GVWR/GCWR
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- GVWR is Gross Vehicle Weight Rating. It is the rated capacity of the vehicle, and includes cab/chassis weight, body and payload weight, fuel, driver and occupant weights, tools, chains, wheel chocks, fire extinguisher and anything else in or on the vehicle.
- GCWR is Gross Combined Weight Rating. It is the rated combined capacity of the truck and trailer it is towing. This includes the GVW of the truck, plus the weight of a trailer and all payloads on the trailer.
- Note: If the GCW exceeds 26,000lbs a Commercial Driver License (CDL) may be required. Some states enforce this rule by adding the GVWR of the Truck to the GVWR of the Trailer, and not the actual loads being carried.
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