There are six types of bearing configurations on light and medium-duty vehicles. The configuration will determine the actual axle nut torque specs to be used. Check manufacturer's recommendations for specific values.
Adjustable Tapered Roller Bearing
These are common on older (pre-1990) vehicles with drum brakes. Especially medium-duty and four wheel drive (4WD) vehicles. It will consist of a cover, an axle nut with a cotter pin, two or three bearings, and a rear bearing seal and flange. Typical torque values are between 180lb and 250lb, depending on application.
Simplified Hub Nut Driveshaft
This configuration has a drive shaft connection running through several bearing components to receive a hub nut. All of this typically resides behind the rotor and other components. This is a common configuration for both front wheel drive (FWD) and 4WD vehicles of later model years. Typical axle nut torque specs will be between 145lb and 180lb.
Simple One Piece Bearing
These are the most common on late model vehicles with rotary brakes. The brake rotor rides over the hub bearing which is all in one piece so that the whole assembly comprises only four pieces (hub, bearing, rotor, nut) and sometimes a cap. Common on most FWD and rear wheel drive (RWD) vehicles. Typical torque values are 145lb to 180lb.
Multi-Part Rotary Bearing Hub
These are the earlier, less simplified version of the Simple One Piece configuration and are common on earlier model 4WD trucks (pre-2000). They are similar to the Simple One Piece setup, but have several bearing units that pack together along the hub rather than a one-piece unit. Torque values are typically the same as above.
Full Float Rear Axle
Heavier vehicles, such as medium- and some heav-duty trucks, will have this system. It's a heavier, drum brake version of the Simple One Piece configuration, but involves four bearing units rather than just one. Typical torque values for hub nuts are between 180lb and 250lb.
Spaced Simplified Bearing Unit
Common on foreign vehicles, especially European imports, these are similar to the Simplified Hub Nut Driveshaft above. They use spacers to separate the inner and outer bearings and often have two hub nuts - one standard, one a castle nut. Typical torque values are between 140lb and 180lb.