Hub-and-spoke conspiracy involving other actors who are cooperating with the hub in carrying out the scheme. It is controversial, particularly in the antitrust cases, how much knowledge spoke actors must have of the conduct of other spoke actors—which is to say how much of a "rim" must be put around the "wheel" of the hub-and-spoke conspiracy for it to be a single conspiracy rather than many separate "vertical" conspiracies. There is a controversy and some uncertainty over the legal status of the "rimless" conspiracy—one with very limited interaction among the spokes. The leading two Supreme Court cases were "Interstate Circuit" and "Kotteakos".
Bicycle wheel Brass nipples are heavier than aluminum, but they are more durable. Aluminium nipples save weight, but they are less durable than brass and more likely to corrode. A nipple at the rim of a wheel usually protrudes from the rim towards the center of the wheel, but in racing wheels may be internal to the rim, offering a slight aerodynamic advantage. A wheel can be formed in one piece from a material such as thermoplastic (glass-filled nylon in this case), carbon fiber or aluminium alloy. Thermoplastic is commonly used for inexpensive BMX wheels. They have a low maximum tire pressure