The Only Pad Fit for our Portola Bike Helmet
One of the challenges we encountered when creating a custom fit, 3D printed helmet is that even for the same individual, the ideal fit can change throughout the day, the time between hair cuts, and whether or not a cycling cap or beanie is worn underneath the helmet. Having the ability to 3D print a helmet within 25-micrometers doesn't matter a whole lot when what's measured varies by several millimeters. Naturally, most people want to have at some wiggle room to accommodate everything from a new haircut to a head covering for those nippy morning rides.
While we could have just created yet another occipital lock mechanism
we felt this was another example where something is added to a helmet as a workaround for a more fundamental issue. Auxiliary fit mechanisms add weight, complexity and can break with frequent use. Since occipital lock mechanisms cinch the head, the trend is to add MIPS on top of that to enable rotational movements of the helmet. Adding MIPS is itself a workaround for isotropic materials like EPS foam where tuning them for linear compressions hampers their ability to absorb rotational energies.
Instead, we went with an elegant solution that solved both fit and rotational attenuation in one simple mechanism.
Introducing Constant Force Pads. There's a sweet spot in helmet pads (the Ideal Feel spectrum above) - tight enough to keep the helmet firmly in place, but loose enough to avoid indents on your forehead after a ride. Our patent-pending pads provide the same amount of force on your head across a wider range of compression. So throw a cap on and you have the same tailored helmet fit as without.
Welcome to the Future
Finally, the pads are a convenient fidget device. Bored while waiting in line for your morning coffee - take off your helmet and you have hours of entertainment at your disposal!