Repeated small helmet impacts from passenger against back of my helmet - Damaged?
I have a question concerning the small impacts that my passenger's helmet is getting against my helmet when I decelerate or brake.
Basically as of the last couple of weeks I've been ridding with a lady as a passenger on my 125cc cruiser until I could get my hands on my 2007 VN 900 Classic (next week I'll be riding the big 900).
As some of you may know, 125cc cruisers are smaller and shorter than the mid-size cruisers, hence she (as a passenger/pillion) sits right behind me with her body touching the back of my body. She is new to riding as a passenger on a bike (she's new to bikes too), so every time that I brake or decelerate, her helmet will hit the back of my helmet.
The impacts from her helmet against the back of my helmet are not hard impacts by any means, and the distance traveled by her head (with the helmet on) before hitting the back of my helmet is only between 2 to 8 inches of distance. However, during a 2 hour ride, these small impacts can easily occur over 20 times as she is getting used to wrapping herself around my body as a passenger.
My main concern if is these small repeated impacts could harm her helmet. The main impact area (on her helmet) is the temple area of the helmet, as she usually has her head resting on either of my shoulders (hence most impacts occur only over a distance of 2 inches).
When an impact occurs (her helmet against mine), we only hear a "clunk" noise but we don't feel it in our heads at all. Only once did we hear a louder clunk noise when I had to do a quick emergency break due to a car pulling on the street. We were travelling at only 20 miles an hour and the bike didn't even come to a stop (just a harder braking than usual). However, she wasn't wrapped around me properly as we were riding around town so her helmet did hit mine a bit harder than usual, but the impact was still small enough to not even feel it in our heads. I didn't even worry initially about the impact harming the helmet.
If it helps, the helmet that I bought her and which she uses is an ARAI Freeway helmet (expensive but well worth the money for an open-face helmet to use around town). I inspected her helmet and there are no scratches or cracks. The helmet is the new 2016 model so it has some nice drawings on it, hence, if the helmet was scratched, I would see the scratches clearly. If I feel the inside of the helmet (without removing anything), it all feels fine.
I've contacted ARAI so they will probably get back to me in the next couple of days. I also believe that I can send them the helmet for inspection with no cost. However, I'm thinking that companies like ARAI (premium helmets) may take into account these common impacts (or maybe they don't?).
As said, the impacts are very light and small, but they are repeated over the course of 2 hours of riding with her as the passenger. We've ridden together about 6 to 8 times and every time that we ride together, she will hit her helmet (temple area) against the back of my helmet more than 20 times. It's the repeated small impacts that worries me as perhaps it could have damaged the helmet and have it lose its efficiency at protecting her head in case of an accident, but maybe these are commonly known and nothing-to-worry-about impacts?
I am aware that helmets will protect your head once in the case of a hard impact, and I've read some great reviews of ARAI helmets sustaining some good damage and still not deforming (i.e. still being able to protect one's head). However, I've also read that ARAI helmets won't show any sign of damage even though the soft protective-foam layer may be cracked or deformed.
Appreciate any help.