Schwalbe Dirty Dan The specialist for sludge. For deep soils and soft terrain. Aggressive open tread with large blocks. Excellent brake traction and extremely good self-cleaning characteristics thanks to the large stud gaps. With extra-grippy ADDIX Ultra soft Compound. Downhill version: Especially robust, double carcass design with Downhill Apex, clincher tires. ADDIX Ultra Soft. Super Gravity version: Puncture-proof (with Apex) with extreme lateral stability for a dynamic ride. ADDIX Ultra Soft.