I find it hard to believe and laughable that a self-professed helmet proponent expert is telling people they can modify their helmets by hitting them with a hammer.

If you are prone to wearing a helmet and find that you are a hard fit, before you go taking a hammer to a new, potentially expensive piece of gear, try on different models from different companies. Very often, variance of fit between companies and models is large enough to accommodate nearly every head size and shape.

As a PT bike shop employee who sells helmets, I would never advise that a customer modify their helmet like this, and I believe my boss would cringe from a liability standpoint to hear me voicing such instruction.

And, also: