Originally Posted by
operator
Thanks, you qualify as dumb.
Go look on 99.999% of the bikes out there with threadless headsets. Are the top caps gone? Didn't think so.
That was uncalled for, even for you.
I agree that it makes sense to leave the top cap and nut in place, if only for convenience or to avoiding losing them, but they are not absolutely necessary if the stem has enough hold to retain the adjustment.
I do race service for events, and often need to share the top cap assembly between two bikes when someone is missing parts or a similar reason. Having done this a number of times I assure you that it kept lots of folks in the race, and none have ever DNFed because of a headset problem.