Casino wheels are large circular rotating devices featuring numbered pockets designed to pay winning bets. A croupier spins the wheel by spinning a ball around an internal track running around it; eventually losing momentum and landing one of thirty-seven (European or French style roulette) or thirty-eight (American style roulette) pockets on it; upon which, winning bettors are paid out by their croupiers.
The roulette wheel was first invented in the 17th century and quickly gained international popularity due to its simple rules and high winning odds. The wheel itself features compartments or pockets containing colored and numbered segments with a central hub which holds the pointer used by croupiers rubbing against pins on the wheel to impart friction that slows it down so players can select winning numbers easier.
Serious casinos employ wheels with at least 27 to 30 inches in diameter and require their balls to comply with specific specifications, such as being made from ivory or another suitable material. 18mm and 21mm balls are commonly found on most wheels and can be arranged accordingly to the pockets size - larger pockets increase the likelihood of the ball jumping, creating more excitement for thrill-seekers!
Many manufacturers specialize in roulette wheels, and a few have become known for designing wheels with unique designs that cater specifically to certain players' needs. For instance, some wheels feature curved pockets to prevent balls from jumping too easily - ideal for players placing Tiers and Voisins bets; other wheels have small yet even frets which increase chances that a ball will land in its intended pocket.
All regulated casino roulette wheels must meet certain standards to ensure that they are random and fair; however, this doesn't make cheating impossible! Some players and dealers have leveraged their knowledge of roulette to devise systems designed to predict when it will most likely hit particular numbers. While such schemes won't likely work in a regulated casino environment, they do give the house an advantage over individual players. Deliberately slowing the wheel can prevent these systems from working effectively. They achieve this by altering the number of frets on the rotor or loosening pocket separators - though this should generally not be done publicly as it would draw undue attention from other players.