While the individual selections in these categories seem rather simple, they can have a significant impact on the final performance of the truck, he points out.
Great care needs to be taken when developing specs to ensure they meet the needs of the intended application of each vocational truck, he stresses. Under-spec’ing can lead to premature component failures, resulting in unscheduled repairs and additional downtime, plus increased life cycle costs. Over-spec’ing adds unnecessary weight to the vehicle, increasing the cost of daily operation through lowered fuel economy and added stresses.
Not to be overlooked is the importance of reviewing the maintenance histories of existing vehicles in the fleet, Johnson counsels.
Vocational trucks used in off-road applications are subject to different types of wear and stresses compared to their on-road counterparts. Failure points depend on type of equipment, operating environment, duty and drive cycles and overall quality of maintenance.
Typically, the most neglected items on vocational trucks are the work equipment installed to adapt the vehicle for a specific job, he says. All too often, maintenance on this equipment, if performed at all, is limited to servicing easily visible or accessible grease fittings.
Look for common failure patterns to see if there are areas where vehicle specifications may need to be upgraded, he advises.
Going through this process can also alert you to other potential issues within your operation. If a particular truck has higher maintenance costs than similar vehicles in the fleet, that truck’s driver may be responsible. A high incidence of repeat repairs within a short period of time may indicate poor maintenance and repair.
Johnson suggests performing a final weight distribution and capacity analysis, incorporating all of the options and accessories added to the vehicle. This will ensure that the completed truck still has the necessary payload capacity and that the individual axles are not overloaded.
If the original chassis selection was marginal, you may have to go back to the initial chassis selection process and make changes in the foundation components or even select a larger truck, he says.