There are two types of wheel attaching parts available today. There is the Ball Seat Piloted & Hub Piloted. The ball seat is declining in popularity on newer vehicles and the Hub Piloted is increasing in popularity in North American markets. Lets look at each type a little closer.
Ball Seat Mounted Type; the ball seat type uses an inner and an outer cap nut. The wheel is piloted by the .875 ball seat on the hub. The wheels are centered and clamped by the ball seats. This type of mounting uses right hand threaded nuts and studs on the curb side and left hand on the driver side.
Hub Piloted Mounting Type; This style uses the wheels inside diameter & pilots located on the wheel hub to center the wheel. Since the elimination of the inner cap nut there is less hardware that Ball Mount. An threads are right hand and are normally metric thread.
When installing all types of wheel attaching parts you MUST inspect for visible damage to the rims. You also at that time check for RUST LINES. These rust lines indicate that the ball seat mount has not made full contact. Some of the causes of that are loose joints and/or worn nut ball seat or wheel. These conditions can cause wheel/or stud failure.
All parts must be inspected for damage. Failure to do this can cause loss of torque cracked wheels and a loss of wheel possibly. Wear on the inner and outer ball seat nuts must be inspected also. If there is wear on the nuts they are not making full contact with the wheel. It should also be regular procedure to clean all mating parts and be sure they are free of lubricants and foreign build up. If there is lubricant on the attaching parts the torque value changes and they may not be torque to proper specifications.
The wheel studs should also be inspected for damage or wear. If the threads are damaged or worn the torque value reading may be incorrect. These can cause wheel failure as in a loss of wheel or loose wheels. When the studs break there is a couple of rules to follow. If one wheel stud breaks you MUST replace both studs on either side of the broken stud. If two studs break or fail you MUST replace all the studs. The reason for this is that the studs on either side of the broken stud have been taking the load for the broken stud. When two fail the load is stressed over the whole wheel and all studs Must be replaced. Also studs should be PRESSED in not pounded with a hammer. This will make sure of complete and proper seating, eliminating stud failures and loose wheels. When installing the wheels it should be good practice to place the wheel on the hub, making sure not to damage the threads on the studs. Place two nuts 180 degrees apart to center the wheel. Then install and tighten the other nuts to 50ft. lbs. Tighten them down like you do in your small car, 9 o'clock then 3 o'clock, then 12 o'clock and 6 o'clock and so on.
Torque values should be rechecked after 50 to 100 miles after installation. During regular service intervals or every 10,000 miles after that. You must check and re-torque in the same sequence and stated above.
When installing HUB PILOT MOUNT TYPE wheels it is still important to check for visible damage or wear. The main thing about hub piloted type is that there is less hardware. This type consists of a right hand thread stud and a flange nut, for both sides of the truck. The clamping force is transferred by the flange type of the nut.
When mounting, rotate the hub until one pilot pad is top center 12 o'clock. Place inner wheel on hub carefully not to damage anything and fit tightly. Then make sure the outer wheel fits snugly against the inner. Then finger tighten all nuts. Tighten all nuts to 50 ft. lbs. , do not tighten fully until the wheel is seated. Then torque to specifications. Again these torque values must be rechecked after 50 – 100 miles. Also during every service maintenance or 10,000 miles.
NOTE: Remember its easier to break a stud sideways that it is to stretch a stud to its breaking point. When your wheel attaching parts are loose you are putting side load on the studs that they are not meant to withstand. ALWAYS use recommended torque specifications.
Mounting type Nut thread Torque level
Hub piloted with 11/16 –16 300-400'lbs (oiled)*
Flange nut M20 x 1.5 280-330'lbs (oiled)*
M22 x 1.5 450-500'lbs (oiled)*
Stud-piloted, double ¾ - 16 450-500'lbs (dry)
Cap nut-standard type 1 1/8 – 16 450-500'lbs (dry)
(7/8) ball seat radius)
Stud-piloted, double 15/16 – 12 750-900'lbs (dry)
Cap nut-heavy duty type 1 1/8 – 16 750-900'lbs (dry) (1 3/16 ball seat radius) 1 5/16 – 12 750-900'lbs (dry)
* When using oil ALWAYS check with recommended assembly procedures. Some attaching parts torque value is based on lubricant. Check for proper lubricant type and amount for specified surfaces.