[kragen]

The rubber can also be synthetic, but natural rubber is longer-lasting. The other ⅔ of the tire are mostly carbon black, which is much cheaper than natural rubber and enormously increases the rubber's wear resistance by making it harder. This also improves fuel efficiency by reducing rolling resistance. As https://en.wikipedia.org/wiki/Carbon_black explains:

> The highest volume use of carbon black is as a reinforcing filler in rubber products, especially tires. While a pure gum vulcanization of styrene-butadiene has a tensile strength of no more than 2 MPa and negligible abrasion resistance, compounding it with 50% carbon black by weight improves its tensile strength and wear resistance as shown in the table below. (...) Practically all rubber products where tensile and abrasion wear properties are important use carbon black, so they are black in color. Where physical properties are important but colors other than black are desired, such as white tennis shoes, precipitated or fumed silica has been substituted for carbon black. Silica-based fillers are also gaining market share in automotive tires because they provide better trade-off for fuel efficiency and wet handling due to a lower rolling loss. Traditionally silica fillers had worse abrasion wear properties, but the technology has gradually improved to a point where they can match carbon black abrasion performance.

So, does this new technique have implications for tires? I don't know. Even if it can be applied industrially at scale, it might make tires less abrasion-resistant rather than more so. Or maybe it will increase the abrasion-resistance and tensile strength of the unfilled rubber, permitting the use of less filler for tires that are more expensive but longer-lasting.