Originally Posted by
Bmach
I would love to see a scientific study that proves wearing glasses under the straps of a helmet means that the helmet straps are not properly adjusted ant will prevent the helmet from protecting you.
You can never 'prove' anything scientifically, it's not possible. Like Newton's first law doesn't 'prove' anything about gravity, it only describes and predicts the motion of objects.
"Cyclist head and facial injury risk in relation to helmet fit: a case-control study."
http://citeseerx.ist.psu.edu/viewdoc...=rep1&type=pdf
While this doesn't prove anything, you can see from this qualitative study that anything that deviates from an almost 'ideal' fit the probability of getting an injury was much higher. .
Now in this study it doesn't distinguish if the helmet tipped back or moved to the side because it was too big or if the straps weren't adjusted properly, but you can infer that anything that could lead to these conditions (fit, straps, etc.) can lead to a reduction of the helmet's effectiveness in a crash. But my thinking is if the straps not as tight as they could otherwise be to accommodate glasses underneath or they stretch out then you may be at greater risk of the helmet tipping back than you would be otherwise opening yourself up to injury. But we can't really prove that can we?
My Specialized helmet only says not to wear anything under the helmet and not to attach anything to it like camera or mirrors, but nothing about something under the straps specifically. I guess we'll have to wait for someone to sue for that specific warning to get added by the lawyers! I might be paranoid about safely equipment, but I always ask myself, "Am I paranoid enough?"