Introduction
A spread axle refers to a trailer configuration where two axles are positioned several feet apart from each other, rather than next to each other like a traditional tandem axle. Spread axles help distribute weight more evenly and allow for higher weight limits compared to tandem axles. Knowing the accurate weight of each axle is critical for spread axle trailers to ensure compliance with weight regulations.
Weighing spread axles presents some unique challenges since the axles are spaced further apart. Special methods must be used with truck scales to get individual axle weights. CAT Scale is one of the most popular truck scale networks and provides a standard process for weighing spread axles to get accurate individual axle and overall weights.
This article will provide a step-by-step guide to using CAT Scales to properly weigh spread axle trailers. Proper weighing technique is essential to ensure compliance, safety, and optimized payload.
What is a Spread Axle?
A spread axle refers to a rear axle on a truck or trailer where the wheels are spaced further apart than a typical axle configuration. While a standard tandem axle has the wheels spaced about 4 feet apart, a spread axle can have the wheels spaced 5-6 feet or even more.
Spread axles are common on heavy haul and oversized load trailers. By spacing the wheels further apart, the load weight is distributed over a longer platform. This improves stability and weight distribution when hauling heavy industrial equipment, prefabricated buildings, or other large loads (Source).
Compared to a standard tandem axle, a spread axle trailer can handle heavier loads on the axle while remaining within legal weight limits. The wider stance also provides more sway control for safely maneuvering large loads.
Challenges of Weighing Spread Axles
Weighing spread axles presents some unique challenges compared to standard tandem axle configurations. The main difficulty is that the wheels on a spread axle trailer are spaced too far apart to weigh on a single scale platform. This means the weights of each axle must be measured separately and then added together to determine the combined weight across the spread axle.
Obtaining an accurate combined weight for a spread axle can be tricky. The separate axle weights may not perfectly match due to load distribution issues. Small differences in individual axle weights can throw off the total weight when added together. This uncertainty makes it difficult to guarantee the combined weight is truly accurate.
Spread axle trailers are designed to distribute weight more evenly and allow higher payloads. But this benefit creates difficulties in using standard truck scales to efficiently weigh the total load. The spaced-out nature of spread axles means they require special considerations when it comes to weighing.
Using CAT Scales to Weigh Spread Axles
The Certified Scale Company, commonly known as CAT Scale, operates a network of certified truck scales across North America (https://catscale.com/). CAT scales are specially designed for weighing commercial vehicles accurately. Their certified weighing system is considered the most reliable and convenient way for truckers to obtain legal weights.
To use a CAT scale to weigh a spread axle:
- Locate a CAT scale near you using the scale locator (https://catscale.com/cat-scale-locator/). There are over 1,500 CAT scales in the U.S. and Canada.
- Drive the truck onto the scale following the posted positioning instructions. For spread axles, the instruction is usually to keep the trailer axles together in a tight group.
- Remain in the truck during weighing. The scale will weigh the drive axles first, then trailer axles.
- After the weigh-in is complete, insert payment or CAT card to receive a printed weight ticket.
- The ticket shows individual axle weights as well as gross vehicle weight.
- For spread axles, the trailer axle weights are combined into a spread axle group weight.
The self-service CAT scale weighing process provides truckers with quick, certified weights legally admissible for registered gross vehicle weight and highway weighing.
Positioning the Truck
Properly positioning your truck on the scale is crucial for getting accurate axle and gross vehicle weight measurements. CAT scales are designed with multiple platforms that allow axles to be weighed individually. For spread axles, it’s important to align each axle with its own platform.
The standard technique is to pull forward so your steer axle is on platform 1 and your drive axle is on platform 2. But with spread axles, you’ll need to take extra care. Make sure one axle is fully on platform 2 and the other axle is fully on platform 3. Keeping them separated on distinct platforms is key.
Some drivers pull too far forward, placing their spread axle over platforms 2 and 3. This prevents getting individual axle weights. Other drivers don’t pull forward enough, keeping the spread axle together on platform 2. Both scenarios lead to inaccurate readings.
It can take some maneuvering to perfectly position a spread axle. But taking the time to place each axle on its own platform will ensure you get precise measurements. The weighmaster is there to guide you if needed. Don’t be afraid to pull forward and realign until each axle is properly in place.
Operating the Scale
Once the truck is in position, it’s time to operate the scale to get an accurate weight reading. The first step is to insert your ticket and payment into the automated machine located near the scale. Most CAT scales accept credit cards, and will prompt you to insert your ticket and choose a payment option.
After inserting the ticket and payment, you simply need to watch for the green light on the scale. This signals that the system is ready for you to drive forward. As soon as you see the green light, proceed slowly across the scale.
It’s important not to drive onto the scale until you see the green “proceed” light. Driving on prematurely can result in an inaccurate reading. The system needs a moment to reset between vehicles, so wait patiently for the green light before moving forward.
Once the truck is fully on the scale, remain still until the scale captures the weight data. This usually only takes a few seconds. When complete, you’ll see the red “stop” light illuminate. Carefully exit the scale at this point, driving slowly and cautiously.
Reading the Ticket
The weighment receipt or ticket from the CAT scale will list the weights for each axle group as well as the gross vehicle weight. For a spread axle, the individual axle weights will be combined into one group.
The ticket will show:
- The weight of the steer axle or axle group
- The weight of the drive axles combined
- The weight of the spread axle group
- The weight of any additional axle groups
- The total gross vehicle weight
It’s important to carefully review the weighment receipt to ensure the axle group weights are listed accurately. The spread axle weight will be shown as a single combined number, not as individual axle weights. Understanding how to read the ticket is key to getting proper weights for a spread axle.
Calculating Spread Axle Weight
To calculate the weight of a spread axle, you will need to add together the individual axle weights from the scale ticket and then subtract the weight of the steer axle. Here are the steps:
- Add the weights of Axles 2, 3, 4, 5, and 6 together. These are the individual axle weights that make up the spread axle configuration.
- Subtract the weight of Axle 1, which is the steer axle. This isolates the spread axle weight.
- The result is the total weight of your spread axle.
For example, if your scale ticket shows:
- Axle 1 (Steer): 12,000 lbs
- Axle 2: 17,000 lbs
- Axle 3: 17,000 lbs
- Axle 4: 17,000 lbs
- Axle 5: 17,000 lbs
- Axle 6: 17,000 lbs
You would calculate:
Axle 2 + Axle 3 + Axle 4 + Axle 5 + Axle 6 = 17,000 + 17,000 + 17,000 + 17,000 + 17,000 = 85,000 lbs
Then subtract the steer axle weight:
85,000 lbs – 12,000 lbs (Steer Axle 1) = 73,000 lbs
Therefore, the total weight on your spread axle is 73,000 lbs.
Ensuring Accurate Weights
To ensure you are getting accurate weights for your spread axle rig, it’s important to follow the proper weighing procedures and double check that the weights make sense based on your load.
First, be sure to position the truck correctly on the scale, with the spread axle situated centered over the weigh pads. Go slow and straight when pulling onto the scale. Make sure no wheels are touching the ground off the scale.
Next, watch the weighmaster closely as they operate the scale to ensure proper procedures are followed. Make sure each axle group is weighed individually in sequence from front to rear.
When you get your printed ticket, read it carefully. Check that the individual axle group weights as well as total weights seem reasonable based on your load and experience. If anything seems off, don’t hesitate to ask the weighmaster to reweigh you.
Cross-check the total weight against your permitted weight and what you expect the load to weigh. Make sure your total steer axle weight, drive axle weight, and spread axle weight all align with your load configuration.
Taking the time to properly weigh and double check your spread axle weights will give you confidence you are operating legally and safely.
Conclusion
Weighing spread axles on a CAT Scale can ensure truckers are in compliance with regulations and avoid costly fines for overload violations. While spread axles require precise positioning and careful reading of the weight ticket, CAT Scales provide guaranteed accurate weights. By properly aligning the axles, letting them rest on the scale, and correctly calculating the spread axle weight, truckers can be confident they are within legal limits.
Accurate truck weights are critical for both safety and compliance. Overloaded trucks put undue strain on roads and bridges, while also making vehicles harder to control and stop. Exceeding weight limits defined by federal and state laws can lead to citations, fines, and even impoundment of the vehicle. By using certified CAT Scales and following proper procedures, truckers can avoid citations and operate their vehicles legally on public roads.
