Introduction
CAT scales, often called certified scales, are heavy-duty commercial truck scales found at truck stops and rest areas across the United States and Canada. They are used to weigh tractor trailers and other commercial vehicles for regulatory and safety purposes. The name CAT comes from Catapillar Tractor Company, which first developed these scales in the 1950s.
Weighing trucks and their cargo is important for several reasons:
- Ensures trucks are not overloaded, which can cause accidents and damage roads and bridges
- Provides weight data for government agencies to monitor and enforce weight regulations
- Allows fleet owners and operators to maximize loads while staying within legal limits
- Helps with load distribution to avoid uneven axle weights
CAT scales are known for their durability, reliability, and accuracy in weighing heavy trucks. Using proper techniques on a CAT scale allows truck drivers and owners to obtain certified weight tickets for compliance and operational purposes.
Prepare Your Truck
Before positioning your truck on the CAT scale, it’s important to prepare the vehicle properly. This will ensure you get an accurate weight reading. According to CATScale.com, the first step is to remove any extra weight from your truck.
Make sure to take out all passengers and pets from the cab before weighing. You’ll also want to minimize the amount of fuel, as the weight of a full tank can throw off your axle weight readings. Many experts recommend filling up just enough fuel to get to and from the scale.
Additionally, remove any unnecessary items from the truck bed or cargo area. All cargo, tools, and gear should be taken out. This will allow the scale to capture just the weight of the actual vehicle.
The goal is to have the truck in its lightest state possible, without any variables that could add more pounds to the overall weight.
Approach the Scale
When approaching the scale, it is important to center your truck and maintain a straight path at a steady speed of 2-3 mph. This will ensure that the axles weigh accurately. Going too fast can produce erratic readings. Make sure your truck is centered on the scale – if the wheels are too close to the edges, it can impact the weight distribution. Focus on keeping the truck moving straight ahead without turning or veering. Sudden braking or acceleration can also impact the readings. The key is a centered, straight approach at a constant, steady speed for optimal accuracy.
According to CATScale.com, “Position 1: Your steer axle should be positioned on platform 1 and your drive axle on platform 2. The weighmaster will then ask you to pull forward. Position 2: Your steer axle remains on platform 1 while your drive axle is now split over platforms 2 and 3.” This demonstrates the importance of a straight steady approach to properly position the axles.
Front Axle Position
Properly positioning your front axle on the scale is crucial for getting accurate weight measurements. You’ll want to place your front axle wheels about 12-18 inches onto the first platform of the scale. This ensures that the full weight of your front axle is registered by the scale without going over the edge (according to How To Weigh – CAT Scale). Keep your wheels straight and centered on the platform. If you have a long front end, you may need to pull forward more to get the 12-18 inches.
It’s ideal to place just your front steer axle on the first platform. Having additional axles on the first platform can throw off the weight distribution. Focus on keeping those front wheels in the right spot 12-18 inches back from the edge (RV Weighing | CAT Scale – Fifth Wheel St.).
Engage Parking Brake
Before the scale operator records your truck’s weight, it’s important to engage the parking brake. This ensures the truck stays in position and allows for an accurate reading. According to experienced truck drivers on forums like TheTruckersReport.com, you should “set the parking brake once they get your weights” (Source).
Some drivers prefer to leave the transmission in neutral rather than park to allow the wheels to roll freely. However, using the parking brake is still recommended for safety and measurement accuracy. As one driver on IRV2.com explained, “Do not apply the parking brake, or place your transmission in Park” (Source). The parking brake holds the truck in place without interfering with the weight readings.
Record Weight
Once your truck is properly positioned on the scale with the parking brake engaged, it’s time to go inside the scale house and get your weight ticket. The weighmaster will weigh your axles and print out a ticket with the weights. This is an important document, so make sure to keep it in a safe place like your logbook.
The CAT scale ticket will show the weights of each axle group as well as your gross vehicle weight. It’s key to note these weights on your driver’s log or keep the ticket with your other important documents. Having a record of your weight is necessary for compliance with regulations and can help with load planning on future trips.
Some drivers also like to note the time and location of weighing along with the weights. This can provide helpful records of your load over time and identify any trends in weight changes. No matter your exact system, make sure to record the vital weight information from your CAT scale ticket.
Pull Off Scale
After recording the weight measurements, the next step is to pull your truck off of the scale. It’s important to do this slowly and steadily in order to avoid any accidents or damage to your truck or the scale:
First, release the parking brake that you had engaged while weighing the truck. Release it slowly and make sure the truck doesn’t start rolling backward on its own.
Next, pull the truck forward steadily, either by pressing gently on the accelerator or by placing the truck in low gear and letting out the clutch gradually. Pull forward just enough to completely clear the scale.
Avoid any jerky movements or sudden acceleration, as this can damage the scale. Drive slowly and be aware of your surroundings as you exit the scale area.
Once fully off the scale, you can pick up speed gradually. Be sure to take note of the weight measurements from the scale ticket, as you’ll need those for legal and safety purposes.
Weighing Multiple Axles
When weighing a vehicle with multiple axles on a CAT scale, it’s important to position each axle on the scale platforms separately. This allows you to get individual weight measurements for each axle group.
Here are the steps for properly weighing multiple axles on a CAT scale:
- Pull forward so only your front or steer axle is positioned on platform 1 of the scale. Engage your parking brake.
- Record the weight shown on the scale display. This is your front or steer axle weight.
- Pull forward until only your drive axle is positioned on platform 2. Engage the parking brake.
- Record the weight shown for your drive axle.
- Finally, pull forward so only your trailer axles are positioned on platform 3. Engage the parking brake.
- Record the weight shown for the trailer axle group.
Following this procedure allows you to accurately weigh each axle group separately. Having individual axle weights is useful for ensuring proper weight distribution across your vehicle and compliance with weight limits.
Understanding Your Weights
Interpreting the weights on a CAT scale ticket can seem confusing at first, but once you understand what each weight represents, you can use the measurements to optimize your load and avoid issues like being overweight. There are a few key weights to pay attention to:
Gross Vehicle Weight (GVW): This is the total weight of your tractor and trailer combined. It includes the vehicle’s weight plus any cargo, passengers, or other items being hauled.
Gross Axle Weight (GAW): This shows the weight on each individual axle, front and rear. You’ll want to make sure no single axle is overloaded.
Net Weight: This is the total weight of just the cargo being hauled, excluding the weight of the empty vehicle. Subtracting your truck’s unloaded weight from the GVW gives you the net weight.
Legal Weight Limits: Compare your weights to the legal limits for gross vehicle weight, axle loads, and bridge or road limits that apply based on your vehicle and location. You can be fined if overloaded.
Weight Distribution: The weight distribution on your axles also matters. You want an optimal balance so neither the front nor rear is handling the full load. Improperly distributed weight can affect steering and handling.
Having a solid grasp of these key CAT scale weights allows you to configure your loads safely and efficiently. You can make adjustments as needed to avoid overloading issues or unbalanced weight distribution. Understanding and monitoring your axle and gross vehicle weights is a crucial part of operating safely.
Source: https://www.airforums.com/forums/f238/need-help-understanding-cat-scale-weights-160435.html
Safety Tips
Proper safety precautions should be taken when using a CAT scale to avoid accidents and injuries. Here are some tips:
- Always use caution and drive slowly when approaching and positioning your truck on the scale. Sudden braking or acceleration can cause injury or scale damage.
- Engage your parking brake and chock your wheels after positioning your truck. This prevents accidental movement and rollover.
- Be mindful of hazards like potholes, debris, and uneven surfaces around the scale. Look for good visibility and lighting if using the scale at night.
- Pay attention to weather conditions like rain, snow, and ice that can create slippery conditions.
- Wear reflective safety vests or other high-visibility clothing when working around the scale. This alerts other drivers to your presence.
- Use traffic cones, signs, or barriers as needed to prevent other vehicles from entering the scale area while in use.
- Never exceed bridge weight limits or attempt to weigh overloaded trucks. Overloading can damage the scale.
- Inspect the scale platform and ramps prior to use. Report any damage or hazards to the scale operator.
Following basic safety precautions helps protect you, your truck, and the CAT scale equipment while weighing.