Goodyear moves forward with rice husk ash silica

Here’s an interesting article on Goodyear’s program to source some of its silica requirements from rice husk ash. Not sure about this sentence, though: “Silica currently make up 15 per cent of each tyre Goodyear makes.” I doubt silica content reaches 15% by weight in an ultrahigh performance tire (more likely half of that), let alone every tire Goodyear turns out.