Make no bones about it, the Schawalbe Racing Ron 27. 5 is a serious, no compromises race tire. PaceStar Triple compound, low profile center lugs, and prominent side lugs come together to make a lightweight, fast rolling tire that grips like crazy, especially in the corners. Designed to go head to head with the very fastest in the world, this tire won't let you down when your name is on the line. The Rocket Ron uses Schwalbe's PaceStar Triple Compound, their fastest. Schwalbe engineers recognize that it's not possible for one compound to do it all, so they've combined three to optimize the tire's performance. The low profile tread of the Rocket Ron is fast, and it's still an excellent cornering tire thanks to the U Block shoulder tread. These tread blocks are angled at 20 degrees or so towards the outside of the tire. Compared to the Racing Ralph, the slightly more prominent blocks have been spaced a bit further apart to achieve more void space. This is part of the reason that it self cleans in mucky stuff so you can continue to have traction to drive down the trail and keep the bike upright.A small sipe doesn't quite divide the block, creating the U shape. They work to counteract the lateral forces endured when cornering to maintain traction and to keep the bike stable. This tire is designed to be tubeless ready TL, which means you can say goodbye to pinch flats. A tubeless system allows you to run less air pressure, again enhancing the grip of the tire's tread. Better traction, less vibration, and no flats lead to a great ride. It's necessary to use a liquid sealant within the tire to seal the bead seat and to quickly seal thorn or debris punctures on the trail. The Schwalbe Rocket Ron TL Ready is available in 27. 5 x 2. 1 and 2. 25. Please note: because Schwalbe has optimized this tire to be lightweight, patching in the event of puncture is not recommended.