MIPS’ latest rotational impact protection technology, Integra Split, is soon to be available on an open-face helmet for the very first time. That helmet is the Fox Speedframe RS, a new top-of-the-range variation on the brand’s best-selling mountain bike helmet.It’s not the first time we’ve seen Fox implement MIPS Integra Split. Indeed, it actually debuted on the DH-certified
last Fall. However, the Fox Speedframe RS will be the very first half shell helmet to benefit from the technology. And, Fox will have exclusive use of it for at least one year post launch., in that it is essentially a two-layer system wherein two distinct layers of EPS are separated by the MIPS liner that connects the two via small elastomers that MIPS refer to as “woofers”, owing to them having a shape similar to that of a sub-woofer.
Also, the two EPS layers are of differing densities; the inner layer is designed to manage energy involved in low speed impacts, while the top layer that is in-molded into the helmet’s outer shell is composed of a higher density EPS that is designed to absorb energy involved in higher speed impacts. Clearly, that is a very simplistic way of describing it, as it all works in concert, but that is the basic gist.
How MIPS Integra Split differs to MIPS Spherical is very simple; the inner layer of EPS is actually split into two intercalating plates that can move independently to one another. This can be clearly seen on the model we saw at Eurobike a couple weeks back.
The helmet is finished off with Fidlock’s magnetic closure for the chin strap, with an Ionic+ comfort liner that has been treated to impeded microbe growth, and thus the production of sweat-associated faust.The Fox Speedframe RS isn’t due to hit stores until April 2024. It will retail at $279.95 USD, 249.99 € and £249.99.