BMW Club of Canada
	Club Racing Warning

Club Racing Warning - Wheel Stud Failures

June 13, 2000

Two instances of wheel stud failure were observed at the Putnam Park Club Race this past weekend.

1. Scott Galaba, HP M Coupe - left rear wheel departed company with the car under load; subsequent observation of the bolts indicated that at least two of the bolts had existing fatigue cracks. The bolts were original to the car and had been used in driving schools and competition.
2. Bobby Thrash, KP 325i - lost the left front wheel after corner workers heard a rattle and observed a wobble from that corner of the car. I was not able to inspect the bolts but the safety workers reported all five were sheared off.

Recommendation: wheel bolts should be inspected for fatigue regularly and replaced periodically. A possible improvement would be to allow studs or recommend substitution of OE bolts with after-market hardened bolts.

Jeff Lutes
North Central Regional Race Steward

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Other suggestions for anyone who tracks their car and especially those with modified suspensions using DOT-R tires:

Follow proper torque recommendations; do not overtighten wheel nuts or bolts.

OEM wheels are hubcentric; use an aftermarket wheel which also fits snugly to relieve stress on nuts or bolts.

Use aftermarket wheel bolts or nuts which meet or exceed BMW original specifications for hardness especially when wheel spacers are in use.

Phil Abrami

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Last updated on 04 July 2000.