Many of my past blogs the subject has been on how to order your equipment to maximize the efficiency of your operation. Today I would like to put a different twist on the subject and make it on how to fully take advantages of your trucks particular specifications.
Let’s take a look at my operation for example which is primarily long distance over the interstate highways with vehicle weights between 60,000 and 65,000 GVW. Keep in mind this is my primary operation however there are times when I can be found in the mountains or weighing up to 80,000 lbs. Throughout the past years there has been many aerodynamic and drivetrain changes available to enhance long distance and higher speed operations.
Let’s speak of aerodynamics first starting with the bumper to the back of the trailer. Starting at the front of my 2018 Cascadia Aero X there is an air dam attached to the lower side of my bumper. With approximately 6 inches of clearance to the ground. This is a feature that enhances the fuel mileage of my type of operation. This same feature would not work very well if your truck needed to do off road pickup and deliveries.
Other features that work very well in my type of operation are the full side chassis fairings on the truck and trailer. The cab extenders, aero enhancements between the tandem axles, wide base single tires on truck / trailer, Flow Below wheel covers on truck and trailer, Nose Cone, Fleet Engineers side skirts,and Stemco Trailer Tail, all contribute to an efficient operation at highway speeds. If my operation was to transport logs out of the woods to a saw mill these features would be a detriment to my operation.
Now let’s move on to the drive line. When I first got involved in this program my 2008 Cascadia was equipped with a DD15 455 HP 1550/1750 FPT Eaton Ultra Shift 13 speed transmission followed by 3.42 rear axle ratio. At the time this was an ideal combination of components to maximize my fuel mileage and profitability of my operation.
The drive line later evolved to a DT12 direct drive transmission with a 2.50 final drive ratio. The 2.50 axle ratio with direct drive essentially put the RPM’s of the engine at the same place as the previous 3.42 axle with an overdrive transmission. The only reason for this change was to cut down on parasitic loss while cruising in top gear.
Since then my specifications have evolved to a DD15 400 HP/1750 FPT DT12 direct drive (AMT) transmission with a 2.28 rear axle ratio and now on my current truck 2.16 rear axle ratio. These changes were made to operate at lower RPM’s. The reasoning behind this is an engine operating at lower RPM’s has less parasitic drag. Every component in the engine from the oil pump to the valve train is moving slower which reduces the amount of friction thru slower rotation and in the case of the valve train slower actuation.
This is where I want to go into exploiting the benefits of your truck. Drivers often ask me how well my truck pulls a grade with my current combination of driveline components. My reply is always that it does not pull as well as it would with a lower gear ratio. The next thing I add to the conversation is everything that I lose in speed going up the hill I make up through not having to fuel as often. The reason this conglomeration of driveline components works in my operation is because most of the terrain I operate on across our country is flat and any area that is not flat is half downhill. It is like the song “Two out of Three Ain’t bad” by Meatloaf. This truck excels at flat ground, down hills, and is decent going up grades. If I were only concerned with how the truck pulled a grade the specifications of my truck would be different. However, my interest is in maximizing my profitability through excelling at the overall average conditions encountered in my operation.
The key is picking components which enhance the profitability for your segment of the industry. If for example I were building a logging truck nearly everything would change all the way from the front bumper to the rear license plate.