The Schwalbe G-One R Pro tire pairs a Race Pro casing with a dual-compound Addix Race tread, so a harder center strip cuts rolling resistance while softer shoulder knobs hold their line through corners. We stock it in 700x35, 700x50, and 700x55 (29x2. 2in), covering a tight-clearance road-plus setup on one end and a high-volume rough-terrain build on the other without changing the compound or casing underneath. Angled side knobs pick up the boomerang tread pattern's grip in wet or loose conditions, so the tire holds its line whether the surface is asphalt or loose gravel. What Our Gearhead(R) Experts Are Saying:"I've run the 55mm on chunky doubletrack all summer without a flat, even after clipping sharp shale that would've cut through a standard casing. The widened V-Guard strip sits right under the tread where debris actually hits, so I stopped babying my line through rock gardens."