The new Flat-less tire. After 10 years, we have thoroughly overhauled the Marathon RF. The only true flat-less tire gets a new, dynamic profile and boasts many internal improvements: Rolling resistance. The patented, thick SmartGuard layer, when compared to all generic products, has a significant advantage in rolling resistance. We further extended its lead in the latest version. Recycling. Also in the SmartGuard, we now use a proportion of recycled rubber from old latex products. "Anti-aging" side wall. It now lasts much longer before developing unsightly cracks when subjected to use with too low air pressure.