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").
Wheel stud Wheel stud Wheel studs are the threaded fasteners that hold on the wheels of many automobiles. They are semi-permanently mounted directly to the vehicle hub, usually through the brake drum or brake disk. Lug nuts are fastened onto the wheel stud to secure the wheel. When a wheel is removed for tire changes etc., the stud remains in the hub. Many automobiles instead use bolts to do this, where removable bolts screw into the wheel hub. Wheel studs can be either factory equipment or aftermarket add-ons. The primary advantage of wheel studs over wheel bolts is greater ease for tire