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South Dakota Axle Weight Limits

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Max Legal Weight for GVW under 80,000 lbs and Max Permitted Weight for GVW over 80,000 lbs

Vehicle configuration

Maximum Legal Weight Allowed

The maximum allowable weight for all individual axles and axle groups is limited by statute:

Single Axles - 20,000 pounds
Tandem Axles - 34,000 pounds
Tridem Axles - 42,000 pounds
Other Axle Groups - based on the Bridge Weight Formula.

The weight supported on a tire may not exceed 600 pounds per inch width of tire, if that tire is on a steering axle, an axle equipped with dual tires; or a trailer towed by a vehicle with a Gross Vehicle Weight Rating of 11,000 pounds or less. The weight supported by tires mounted on other axles may not exceed 500 pounds per inch width of tire.

Maximum Permit Weight Allowed

Oversize and Overweight Permits

Interstate-Specific Permits

Only single trip permits are issued for the movement of an overweight vehicle on Interstate Highways.

A permit is available to allow a motor vehicle to exceed 80,000 pounds when traveling on the Interstate Highways. The permit does not allow a motor vehicle to exceed its legal axle weight, legal tire weight, or the weight allowed by the Bridge Weight Formula. Neither does it allow a motor vehicle to exceed its commercial motor vehicle licensed weight.

Single-Trip Oversize/Overweight Permit

If the motor vehicle exceeds the weight of 40,000 pounds on two axles, 60,000 pounds on three axles, 80,000 pounds on four axles, 85,000 pounds on five axles, 90,000 pounds on six axles, and 95,000 or more pounds on seven or more axles, an additional overweight fee is charged at a rate of two cents per ton-mile for the excess weight.

Longer Combination Vehicle Permit (LCV)

The Longer Combination Vehicle (LCV) permit allows specific vehicle combinations to operate on Interstate Highways and other specified State Highways at weights up to 129,000 pounds.

The LCV may not exceed a gross weight of 129,000 pounds, 20,000 pounds on a single axle, 34,000 pounds on a tandem axle or the weight as allowed by the Bridge Weight Formula on any axle group combinations. The weight on a steering axle may not exceed 600 pounds per inch width of tire, and the weight on all other axles may not exceed 500 pounds per inch width of tire. All axles must be equipped with four tires with the exception of the steering axle. A semitrailer or trailer may not weigh 3,000 pounds more than the trailer immediately ahead of it. Lift axles and belly axles are not considered load-carrying axles and will not count when determining the vehicle’s weight limits. Axles that are spaced eight feet or less apart must weigh within 500 pounds of each other.

Source of information: http://www.sdtruckinfo.com/sizeandweight.aspx
http://www.sdtruckinfo.com/docs/MCHandbook_chap5.pdf