2. CDL Endorsements & Restrictions
4. CDL Training: Learn to Drive
4. Seven-Step Inspection Method
8. CDL Training: Seeing Around
14. Managing Vehicles Around You
17. Spot Hazards on RoadCDL Training
24. Vehicle for Winter Driving
25. Drive in Winter Conditions
27. Railroad-Highway Crossings
39. Truck Fire Causes & Prevention
2. Legal Weight Limits for Trucks
3. Passenger Supervision & Accidents
2. Air Brake Systems for Trucks
3. Air-Brake Systems & Foundation
4. Air-Brake PartsCDL Training
5. Air-Brake System Spring Brakes
6. Air Brake Systems for Trucks
7. Dual Air Brake Systems for Trucks
10. CDL Air Brake Check for Trucks
12. Emergency Stops in a Truck
13. Properly Brake on Downgrades
1. Drive Combination Vehicles Safely
3. Handle Railroad-Highway Crossings
5. Combination Vehicle Air Brakes
7. Connect Hose Couplers (Glad Hands)
9. Antilock Brake Systems for Trucks
10. Couple & Uncouple Trucks Safely
11. Couple and Uncouple a Truck
12. Safely Uncouple Tractor-Semitrailers
13. Inspect a Combination Vehicle
2. Couple & Uncouple Trailers Safely
3. Uncouple Twin & Triple Trailers
1. CDL Training: Section 8 Tanks
1. Hazardous Materials Regulations
2. Intent of Hazmat Regulations
3. Hazardous Materials Responsibility
5. Placards & Regulated Products
7. Hazardous Substances & Quantities
8. Fill Out Hazmat Shipping Paper
9. Hazmat Shipping Paper Requirements
10. Recognize Hazardous Materials
12. Load & Unload Hazardous Cargo
13. Load & Unload Hazardous Cargo
14. Loading/Unloading Hazardous Cargo
15. Bulk Packaging Markings, Loading
17. Hazmat Driving & Parking Rules
19. Keep Shipping Papers & Info
20. Respond to Hazmat Emergencies
21. Control Truck Fires & Leaks
22. Respond to CDL Training Hazards
23. Required Notification for CDL
24. Hazardous Materials Glossary
2. School Bus Loading/Unloading
6. Emergency Exit/Evacuation CDL
7. Emergency Evacuation Procedures
10. CDL Training: Special Situations
1. CDL Pre-Trip Vehicle Inspection
2. Inspect Vehicle Parts for CDL
4. CDL Training: Check Oil Pedals
5. Inspect Steering & Suspension
6. CDL Training: Brake Wheel Checkup
7. Inspect Truck for CDL Training
8. Inspect Tractor & Coupling Lines
9. CDL Drivers: School Bus Inspection
10. Inspect Trailer for CDL Training
1. CDL Basic Vehicle Control Skills
1. CDL Training On-road Driving
2. On-Road Driving: Intersections
3. CDL Training: On-Road Part 3
1. Learn Hours of Service Regulations
2. HOS Regulations for Truckers
3. Understanding HOS Regulations
6. 11-Hour Driving Limit for Trucks
8. Adverse Driving Conditions/16hr
11. Calculate Hours with Sleeper Rule
1. Weight & Balance Laws for Trucks
2. Weight Transfer for Truck Drivers
3. Limitations of Axle Spacing
4. Scale Truck for CDL Training
5. Position of Trailer Tandems
6. Load Cargo for Axle Balance
7. Calculate Fuel Weight for CDL
8. Calculate Truck Driver Fuel
9. Calc Fuel Burnoff for Trucks
1. Learn Cargo Securement Fund.
2. Cargo Securement Requirements
4. Learn Containing, Immobilizing
6. Cargo Tie-Downs: Working Load
9. Secure Logs Loaded Lengthwise
12. Secure Metal Coils in Truck
13. Secure Coils Eyes Crosswise
14. Secure Coils Eyes Lengthwise
15. Secure Coils for Truck Drivers
16. Secure Paper Rolls for CDL
17. Load & Secure Paper Rolls Vert.
18. Secure Paper Rolls Vert. CDL
22. Reqs. Arrange Concrete Pipe
23. Securing Pipe Inside Diam. 1.143
24. Securing Pipe Inside Diam. 1143
25. Secure Intermodal Containers
26. Secure Autos, Light Trucks, Vans
27. Secure Heavy Vehicles, Equip.
28. Secure Flattened/Crushed Vehicles
29. Secure Roll-On/Roll-Off Hook
30. Secure Large Boulders Tranport
1. Cargo Securement for Trucks
2. Securement Devices & Dunnage
3. Strength Ratings Blocking System
4. Cargo Roll Prevention Training
8. Securement Reqs. for Metal Coils
9. Securement Reqs. for Metal Coils
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The placement of the cargo in the trailer will have a tremendous impact on the distribution of weight across your axles. Properly loading the cargo will get your axle weights pretty close initially so that a minor adjustment may be all that's needed to get your axle weights legal. Improperly loading the cargo could place too much weight to the front or rear of the trailer, preventing you from being able to balance the weight across the axles properly.
When loading cargo into the trailer, you want to first make sure that you have your trailer tandems within the legal length limits allowed from the kingpin to the trailer tandems for the states you'll be traveling in. You can look up these limits in your Rand McNally Motor Carrier's Atlas. You can slide the tandems as far forward as you would like, but you can only place them as far back as the kingpin to trailer tandem laws allow.
Let's take a look at some factors involved in properly loading cargo.
The center-of-gravity location of the cargo is the center point of the cargo's weight. If all of the cargo in your trailer was one solid block, the center of gravity would be the point that the entire block would balance upon like a teeter totter.
You'll want to have the cargo loaded into the trailer so that the center of gravity is centered between your drive axles and your trailer tandems. If unsure of the exact location of the center of gravity of your cargo, you'd rather have the center of gravity of the load wind up a little closer to the front of the trailer than to the rear. You can slide the trailer tandems forward as far as you would like to compensate for too much weight on the nose of the trailer, but the kingpin to trailer tandem length limitations will prevent you from going too far back with your trailer tandems. You can also physically move some of the cargo toward the back of the trailer if necessary when you have too much weight to the nose.
Here you can see the cargo is properly loaded with the center of gravity centered between the drive axles and trailer tandems.
Here you can see the cargo is improperly loaded with the center of gravity too far to the rear of the trailer.
Here you can see the cargo is improperly loaded with the center of gravity too far to the front of the trailer.
Here you can see the cargo is loaded in the overhang portion of the trailer creating leverage on the trailer tandems.
Everyone is familiar with the concept of using a lever. Using a lever on an object allows you to exert more force upon the object than the amount of force you're actually exerting against the lever itself. In other words, you might rig a lever that can lift a 250-pound boulder but requires only 50 pounds of force against the lever itself. When loading cargo into a 53-foot trailer, leverage can come into play.
When hauling freight in a 53-foot trailer, you will always have some overhang behind the trailer tandems because the laws limiting the overall length from kingpin to trailer tandems won't allow you to put the trailer tandems all the way to the rear of a 53-foot trailer. The portion of the trailer behind the trailer tandems is the overhang portion of the trailer. In figure 4 above, you can see how the cargo is loaded into the overhang portion of the trailer.
Because the trailer pivots up and down at the kingpin above the drive axles, the floor of the trailer acts as a lever pushing down against the trailer tandems when freight is loaded into the overhang portion of the trailer. The further back you load the freight into the overhang portion of the trailer, the more leverage it creates. The net effect of this leverage is that you're putting more weight on the trailer tandems than the cargo itself weighs, and you will actually take a little bit of weight off the drive axles at the same time. This can be used to your advantage, or it can work against you, depending on your circumstances.
We're going to spare you the formulas and mathematics of leverage, but I'll give you an example of what you're dealing with. If you load a 100-pound box 10 feet behind the center point of the trailer tandems, you will add about 120 pounds of weight to the trailer tandems, and take about 20 pounds of weight off of the drive axles at the same time.
This is another reason that when you're estimating a load's center of gravity, you'd rather load the freight with the center of gravity a little closer to the nose than the rear. If there is room enough to do so, you can always move some of the cargo to the very back of the trailer to help balance the weights properly when sliding the tandems all the way forward won't do it.
If you load cargo into the overhang portion of the trailer, what will be the result?
If unsure of the exact location of the center of gravity of your cargo, where would you rather have the center of gravity located if you couldn't get it centered?
What will be the ultimate limitation that prevents you from putting the trailer tandems as far to the rear of the trailer as possible?
Where in the trailer could you place cargo so that the weight applied to the trailer tandems is greater than the weight of the cargo itself?
What is the cargo's center of gravity?
If you are able to exert 200 pounds of force against an object but you are only exerting 50 pounds of force to do so, what method are you applying to make this happen?
Ideally, where would you like the cargo's center of gravity located?
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