Bicycle wheel some other fixed point may be used as a reference mark, however this is less accurate. At one end of each spoke is a specialized nut, called a nipple, which is used to connect the spoke to the rim and adjust the tension in the spoke. The nipple is usually located at the rim end of the spoke but on some wheels is at the hub end to move its weight closer to the axis of the wheel, reducing the moment of inertia. Until recently there were only two types of nipples: brass and aluminum (often referred to as "alloy").
Rim (wheel) rim and then being welded together. The disk is welded in place such that the center of the wheel is equal to the center of the hub. The distance between the centerline of the rim and the mounting plane of the wheel is called the "offset" and can be positive, negative, or zero. One-piece rim and wheel assemblies (see image) may be obtained by casting or forging. The terms "wheel" and "rim" are often incorrectly used synonymously, as in decorative wheels being called rims. Used broadly, or used figuratively, the word "rim" can mean the outer edge of any circular