Scaling a tractor trailer is not something that a lot of time is spent on in a driver’s training program. However, scaling and having accurate and legal weights is an important part of the job. Overweight loads, or loads whose weights are not evenly distributed over their axles can cause drivers excessive fines and wasted time. It is not a complicated process, but it does take some practice.
Scaling a Tractor Trailer
- Lock the trailer brakes.
- Load the steering axle first.
- Lower the landing gear, unlock the fifth wheel, and dump the tractor airbags. Back the truck up toward the trailer until the tractor is as close to it as it can safely be without affecting the truck’s ability to turn. When a driver has determined the distance is safe and correct, lock tee 5th wheel in place. Inflate the tractor airbags and raise the landing gear.
- Release the slider pins. While the trailer brakes are still locked, release the slider pins. The general rule of thumb is about 400 lb. per hole on the trailer slider.
- Scale the truck and adjust accordingly.
- Stop with only your steer axle on the platform to get your steer axle weight.
- Continue until both the steer axle and the drive tandems are on the platform. (This will give you the tractor weight.)
- Subtract the steer axle weight from the tractor weight. (This will provide you with the weight of the drives.)
- Pull on the platform to get the gross combination weight.
- Subtract the tractors weight from the gross combination weight. (This will give the driver the weight of the load on the trailer tandems.)
All weights can be verified as a driver pulls off the scales. Many public scales are set up with three platforms to check the three axle groups at once. However, many state scale houses only have single platforms. Knowing the information stated above will save a driver time scaling their tractor trailer.
Important Information for Scaling a Tractor Trailer
- Do not slide and adjust on the scale plate.
- Leave room for extra weight on the drives to allow for the weight of fuel.
- In the winter months, leave weight on the drives to help with traction when climbing hills to prevent spinning out.
- Always do adjustments on a flat, dry surface.
- Always remember that the process varies according to the number of axles and the rules and regulations dictated by the state a driver is in.
Following these scaling procedures will save a driver time and keep them out of trouble at the scales.