Schwalbe Rock Razor The semi-slick. Used on very fast and dry trails. Little rolling resistance and little weight. Primarily for use on the rear wheel. Tread design: fast, flat studs in the centre of the tread for good corner grip with sturdy lugs on the tyre shoulders. Super Gravity version: Puncture-proof (with Apex) with extreme lateral stability for a dynamic ride. ADDIX Soft. Tubeless Easy version: ADDIX Speedgrip. In 27.5+ also with Apex. More information: