Originally Posted by
livedarklions
I see what you're talking about.
So is the Bontrager claim that the CELL technology produces more protection from both "linear and rotational forces" nonsense? Honest question.
Looking at it a little closer, the liner in a WaveCel is basically a different kind of foam--the gel material is arranged in a lattice with lots of air spaces, and I think the air spaces collapse on impact both linearly and rotationally then bounce back. Definitely contained in an EPS shell, so there is a layer of the conventional.
The claim isn't nonsense, but it's theoretical and based on bench testing. I can say pretty confidently that there will never be prospective clinical or animal data on the subject. I think my next helmet will be something of the kind, but, having some knowledge and experience in this area, I have little faith in the ability of bicycle helmets to mitigate anything but skull fractures and brain contusions, both of which are related to direct, linear, forces. They are both potentially catastrophic and completely worthy mitigating, but not nearly as common as concussion.
On the gel issue, fluids are incompressible, but fluids in stretchy spaces, constrained to flow through little holes, or with lots of intrinsic viscosity, absorb energy by their resistance to flowing away from the area of impact.