Monday, May 20, 2013

What Can Cause Your Wheel to Pop off at the Track

All 5 lug bolts busted off the hub under heavy braking

I had a fantastic student with a very unfortunate mechanical failure at speed at Watkins Glen last weekend. We were entering the braking zone for the toe of the boot ~ 90 mph when the front driver side wheel popped off and got stuck at a 45-degree angle inside the wheel well. We were just passengers at that point and went into the tirewall. Luckily, it happened at a turn that goes uphill, which slowed us down significantly before we hit the tire wall at < 30 mph. Failure analysis of the hub with broken studs revealed one stud failed in yield and was likely caused by a stress riser at the end of the hub thread. This is definitely one thing you may want to check in your car before your next track event.