There are 3 hub and bearing configurations. The most common today is the unit, or integral hub and bearing assembly that often includes the ABS sensor. These cannot be disassembled and are replaced as a unit. Some hub unit bearings on front wheel drive vehicles require removal of the steering knuckle, and the bearing and hub are then pressed apart and back together. Finally, there are non-driven axle hubs with opposed, replaceable tapered roller bearings.
Non-quick release hub systems use axle nuts and washers on the outside of the dropouts to hold the wheel in place. Adjustment of solid axle hub bearings is similar to the hollow axle quick release type, but there is no need to allow for axle flex. Mount the wheel in the frame similar to quick release hubs as described above. Tighten the axle nut inside the dropout that is holding the wheel. The axle is now held tight. Check for bearing play. If no play is present, create play by loosening bearing adjustment, then adjust in small increments until play in gone. The goal is to find the loosest adjustment that has no play. Remove the wheel from the bike. The adjustment for solid axle hubs does not change when mounted in the bike.
Hub unit bearings have to meet increasingly strict requirements that demand lighter weight, greater promotion of fuel efficiency, and enhanced module production systems. Along with the widespread adoption of antilock braking systems (ABS) to ensure stable maneuverability during braking, there is a growing need for our hub unit bearings with a built-in sensor. NSK guarantees high quality of all of our products by repeated, rigorous bench testing and other checks that take full advantage of our cutting-edge technology, which only the top-bearing maker can offer. NSK offers compact and lightweight hub unit bearings with built-in ABS sensors.
Quick release hubs have hollow axles that flex slightly when the quick release is closed. Hub bearing adjustments must account for this extra pressure. When a quick release hub is not clamped tight in the frame, there should be a slight amount of play in the axle. This play disappears when the hub and wheel are clamped in the frame.