RMAT

When Hoka were taken over by Deckers in 2013, they started to use a new type of foam in some of their shoes called RMAT (sometime R-MAT). I've found that the claim that RMAT shoes last longer is well justified. However, I've also found that the early versions of RMAT made the shoes far too heavy and too firm.

• This foam, produced by Xinyilai Rubber Goods, is actually a type of rubber that is intended to combine the features of rubber and foam.
• RMAT has better grip than EVA foam, allowing it to be used without an outsole. RMAT also has far better wet grip than hard rubber outsoles.
• RMAT is more resistant to the gradual reduction in height that happens as foam wears out, making it last longer.
• Xinyilai claims that their rubber has better cushioning characteristics than traditional foams. However if you look at the graphs below, you can see that RMAT does much worse until 10,000 cycles. It's unclear how the cycles are performed, but in the few hundred miles I've run in a pair of early RMAT shoes, I saw no improvement.
• RMAT is produced as an insole, midsole and outsole.
• RMAT is continuing to evolve, and the RMAT logo includes a number indicating the version.
• RMAT 3 is claimed to have a shorter break in period, and better cushioning than earlier versions.

A chart of energy return (higher is better).

A chart of cushioning (lower is better).