Crash pads have two major elements — the inner foam that provides cushioning, and the outer covering that offers abrasion resistance and durability.
On the inside, two kinds of foam are usually layered to create an effective system of impact distribution and absorption. Open-cell foam is easily compressible because the air within each cell can seep out under pressure. This kind of foam gives a pad its plush cushioning qualities.
Closed-cell foam is more rigid and doesn’t soften when compressed. Inside a pad, the layer(s) of closed-cell foam will be thinner than the layer(s) of open-celled foam. When layered, these two types of foam combine to dissipate and absorb impact.
To contain the foam and protect it from the elements, most pads employ thick nylon covering. Nylon fabric has a denier count, which basically conveys the thickness of the material.
For crash pads, look for at least a 1,000-denier count. When you’re dragging your pad across the forests of Squamish or the deserts of Bishop, you’ll want to know that your pad can hold up to constant abrasion.