For Allowable Vehicle (Truck) Loading in Michigan Refer to Michigan Compiled Laws Section 257.722.  The following information shall only serve as a quick abbreviated guide and does not supersede any rules or laws of the Michigan Compiled Laws previously referenced.

Maximum loadings permitted in accordance with Michigan laws are as follows:
11,700 pounds per single axle vehicles
20,800 pounds on tandem axle vehicles
with one tandem assembly (2 Axles)
16,900 pounds maximum for all other tandem assemblies

This maximum allowed loading reduces the normal loading 35% during the spring while the frost is going out of the roadbed. Allowable speed limit for trucks on county roads during this period is reduced to 35 mph. These restrictions will be lifted after all the frost is gone and the roadbeds have dried out sufficiently. 

Maximum allowable gross axle loading on all weight restricted roadways (NOT All-Season Routes) are:
Single Axle:  11,700 lbs.
Tandem Axle:  10,400 lbs./each axle
Any other axle having another axle within 9 feet: 8,450 lbs./each axle
(On any legal combination of vehicles only one (1) tandem axle assembly shall be permitted at the gross weight of 10,400 lbs. per axle and no other tandem axle assembly in such combination of vehicles shall exceed a gross weight of 10,400 lbs. per axle.)
Maximum load on any tire shall not exceed 450 lbs. per inch of tire width.  Maximum speed 35 MPH for trucks over 10,000 lbs. GVW.