Information about bicycle wheels
For the mounting of bicycle wheels, each frame/fork has specially designed dropouts. The most common techniques to fix the wheels are the quick-release (develpoed by Tullio Campagnolo) and the fixed axle (thru axle). A wheel is made up of mutiple bicycle components.
A wheel consists of a rim, a tire, spokes, nippels and a hub. The hub is in the middle of the wheel. High quality axles and the bearings are providing a low rolling resistance. The spokes are combined with the hub. The rear wheel hub has usually a freehub (device for the installation of the sprocket).
Especially for mountain bikes, the hubs have an appliance for mounting disc brakes. The brake disc can be attached in a variety of ways using bolts or a central locking ring.
For the non-professional use, rims are manufactured of aluminium alloy. Rims designed for use with rim brakes provide a smooth parallel braking surface, while rims meant for use with disc brakes or hub brakes sometimes lack this surface.
For the professional use, the rims are fully carbon made. The reason is to save weight, but carbon fiber is a really expensive material.
The rim is connected to the hub by several spokes under tension. Every spoke is fixed with the rim by a nipple.