Start by separating an axle-distribution problem from a gross-weight problem. Sliding trailer tandems transfers weight between the drive and trailer groups. It does not change gross.
- Check steer, drives, trailer, and gross against the limits that apply to the equipment and route.
- If only the drives are heavy and the trailer has capacity, move the trailer tandems toward the tractor.
- If only the trailer is heavy and the drives have capacity, move the tandems toward the trailer doors.
- If both groups are heavy, gross is over, or there is not enough rail, stop treating it as a slider problem. The freight may need to be reworked or removed.
- Reweigh after the adjustment.
Before choosing holes, subtract the receiving tandem's current weight from its applicable limit. That is the most weight it can accept in the simplified transfer model. If the drives are 1,800 pounds heavy but the trailer has only 900 pounds of room, a tandem slide alone cannot put both groups under those limits.
Leave room for the real constraints
A mathematically balanced ticket is not automatically ready for the road. The target position must exist, the pins must lock, and the position must comply with applicable state length or kingpin rules. Equipment GAWR and tire ratings can be lower than a statutory maximum. Bridge Formula can also control a group of axles even when each familiar axle limit appears satisfied.
If the numbers do not point to a clear slide, call dispatch, safety, or the person responsible for the load plan. Guessing farther down the rail is not a substitute for fixing the load.
A steer overage is a separate problem. Depending on the actual ratings and rules, the answer might involve freight placement, fuel, the fifth wheel, or a tractor-specific limit. Do not move the trailer tandems simply because they are the adjustment that is easiest to reach.