I had a helmet damaged by a roommate who knocked down a bike on a stand. The polystyrene was cracked completely through but remained bonded to the shell. They a

I had a helmet damaged by a roommate who knocked down a bike on a stand. The polystyrene was cracked completely through but remained bonded to the shell. They are supposed to break like that. Older styles of construction are going to be less durable but if it keeps the structure constrained to your head it will to a better job than nothing.