I pulled a wheel last night at the track in the beginning of a practice Team TT. My bike and Wheelset (Jamis Sonik - AC420's) came with those serrated (if that's the proper term as opposed to flat) lock washers. I want to replace the washers even if for no other reason than to restore confidence. Should I replace them with the same style or something different (i.e flat?) to best minimize the chances of a repeat? What do the Professionals use?
You need a good hex wrench to properly torque down those bolts. It should be OK if torqued properly. Maybe you were using a wrench with too small of a lever arm?
(Make sure to retorque those crank arms too, they seem to loosen).
Also, you may have to use a chain tensioner if you are one that produces a lot of torque and your dropouts have steel faces on them. The steel of the wheel nut and the steel of the dropout slide against each other.
if you have the "old style" serrated washers, junk them for the new ones.(Shook integrated bolt system)
plus, dissimilar metals tend to stay together under pressure.(brass washer)