The roulette wheel is composed of a large bowl with slanted edges and a separate mechanism inside that hold an array of numbers. The wheel is about three feet in diameter and about one hundred pounds. At the very center of the wheel is the spinner, which the casino attendant uses to rotate the inside of the wheel as he rolls the marble ball in the opposite direction.
By now we know that there are two versions of roulette. The roulette wheel for American roulette differs from that used to play European roulette in the way the numbers are laid out and the number of pockets. This section analyzes both types of roulette wheel layouts.
There are 38 partitions on the American roulette wheel. The numbers are dispersed carefully, with an emphasis on splitting up the outside betting groups. The colours alternate, as do pairs of odd and even numbers. For example, the first dozen bet is very well distributed around the rotor; with the exception of 11 and 12, they are almost laid out four pockets apart. Take a look at the picture to the right to get a better idea.
The Blanc brothers introduced the European-style roulette after the American style came out. Their goal was to reduce the house edge by removing the double zero from the wheel and it did - almost by half!
When the double zero was removed from the American layout, the brothers were faced with a small issue - red 1 and red 27 were now adjacent to each other. Both being red, the wheel layout had to be re-designed. The numbers on the European wheel don't seem to be arranged with any particular logic. Unlike the American wheel, there is no obvious strategy that has been used to place the numbers other than alternating the colours. Why? Isn't that up to the inventor?
Although there is an effort to spread out the numbers to create a balanced wheel, the odds wouldn't be any different were the numbers arranged 1 through 36 in consecutive order. Each time the ball is spun, the destination of where the ball end up is completely random, regardless of the roulette wheel layout. The main reason why the numbers are laid out the way they are (especially so in American roulette) is to give the game a greater feeling of randomness and balance.