Sheared Wheel Bolts - Wheel Spacer
Pictured below shows five lug bolts that sheared off the car during a race. They were holding on an H&R 25mm wheel spacer. From left to right; the first two bolts look like clean shears, the third and fourth bolts show possible signs at the top of the shear of oxidation of a previous fatigue / stress crack, the fifth one looks like it was trying to hang on for dear life.
Listed below are recommendations that have been presented to prevent future occurrences if the car is used on a track:
- Torque lug bolts to 85 foot pounds, even though the owners manual calls out for 72 foot pounds.
- Replace all lug bolts once a year or so, depending on track use.
- Check lug bolts periodically for any signs of fatigue / stress crack.
- If after-market hardened bolts are used, should be of 10.9 hardness.
- Convert over to studs using steel lugnuts.
