The R45 hubset is 20% lighter than their Classic hubset with a sleek new hubshell bodies and new 17mm axles. That's 17mm from dropout to dropout resisting deflection during cornering or when the power is full on. They have designed a driveshell with a twin bearing design and responsibly removed as much weight as they could from the inner components. Even the patented RingDrive engagement system was redeveloped resulting in a quiet, fast-engaging 45-tooth stainless steel system unique to the R45 rear hub. Read more… Chris King also designed and built a bearing specifically for the R45 hubset. As with every King bearing, these stainless steel sealed bearings are made in-house in Portland, Oregon and individually hand-checked for precision and smoothness. RingDrive™ Engagement Mechanism RingDrive™ uses 72 engagement teeth on each drive ring. This means that the hub engages over 3 times quicker than the standard 24 tooth pawl-type freehub. This unique design offers instant and positive engagement that's capable of handling a torque load of over 800ft/lbs, or over three times more than most other high end hubs. All of Chris King hubs are easily adjustable and simple to work on, requiring only two hex wrenches and a pen knife for regular maintenance.