This link is to a reference for the following series of posts.

https://mechanicalc.com/reference/bolted-joint-analysis#internal-thread-dimensionsThe short bolts attach the brake disk to the adapter ring. The materials and use are the same as before the ring was installed. The factory recommended torque can be used for them. The long bolts are custom made from titanium to fit the adapter. The installation torque needs to be calculated. The bolts will be tightened down to provide the maximum clamping force the threads can withstand.

There are three ways the fastener can fail. One is to strip the internal threads in the wheel. Another is to strip the external threads on the bolt. The last is to break the bolt from tensile stress. This usually occurs across the bolt where the threads meet the unthreaded shank. All three failure types will be calculated. The first will be stripping the internal threads in the wheel.

These are M8 x 1.25 threads and the bolt has an 8 millimeter nominal diameter.

The engagement length will be determined. This is the length of the portion of the threaded hole that is expected to carry the load. According to the reference for a bolt going into a blind hole, the ENGAGEMENT LENGTH = BOLT NOMINAL DIAMETER = 8mm

The thread height, is what it says. The thread pitch is the distance between the threads along the bolt axis. It is 1.25mm

THREAD HEIGHT = [(SQUARE ROOT OF 3)/2] x THREAD PITCH = 1.73 / 2 x 1.25 = 1.08mm

The internal thread pitch diameter needs to be figgered. INTERNAL THREAD PITCH DIAMETER = BOLT NOMINAL DIAMETER - (0.75 x THREAD HEIGHT) = 8 - (0.75 x 1.08) = 7.19mm

It will be assumed the internal threads will tear out at their roots by shear from the bolt. The area of this shear needs to be calculated. INTERNAL THREAD SHEAR AREA = 3/4 x pi x INTERNAL THREAD PITCH DIAMETER x ENGAGEMENT LENGTH = 3/4 x 3.14 x 7.19 x 8 = 135 square mm or 0.210 square inches

The wheel is assumed to be cast from T6 AlSi7Mg0.3 alloy with a minimum tensile yield stress of 200 MPa or 29,000 psi. This yield stress is also applicable to similar alloys used to make wheels. The failure will be in shear and the tensile yield stress will not be appropriate. The tensile yield stress will be multiplied by 0.577 to get the shear yield stress. See reference. SHEAR YIELD STRESS = 0.577 x TENSILE YIELD STRESS = 0.577 x 29,000 = 16,700 psi.

The preload force is the tension applied to the bolt during installation. The maximum allowable preload stress will be 0.64 percent of the shear yield stress on these wheel threads as per the reference. MAXIMUM ALLOWABLE PRELOAD FORCE = 0.64 x SHEAR YIELD STRESS x INTERNAL SHEAR AREA = 0.64 x 16,700 x 0.210 = 2,240 lbs

This is not much. Some thread inserts might be needed in the wheel if there are any indications the threads are stripping. The inserts increase the internal shear area dramatically with a resultant tolerance for increased bolt preload. The next post will be about external thread shear failure.