Roulette is by far and away the most popular wheel game played in casinos today, however even the keenest players have probably given very little thought to one of the most important aspects of the game – the wheel itself.
Roulette wheels have been around for hundreds of years and, while modern wheels may be more consistent and reliable than their older counterparts, the basics of the way they function and operate are the same as they were in 18th Century France.
History of Roulette Wheels
While roulette wheels have always contained numbered pockets that represented the numbers players could bet on during a game, the exact layout of the wheel has changed several times throughout history.
The first wheels that definitely used something similar to modern rules were found in Paris in 1796. The early version of the roulette wheel was similar to the modern American wheel and featured 36 numbers along with a zero and double zero. Early on, one of the zeroes was colored red, while the other was colored black. This was to make it clear that these spots would not win on even money bets. The zeroes were changed to green, a change that has remained to this day.
In 1843 a casino in Hamburg decided they wanted to attract players by offering a better roulette game than their competitors. They realized that even if they made changes that favored the player, roulette could still have enough of an edge for the casino to make the game profitable. This lead to the single zero wheel – a game that remains known as European roulette today.
Meanwhile, roulette was also gaining popularity in the United States, albeit with a rather different style. The roulette wheel in America in the 19th century featured only 28 numbers, as well as a zero, a double zero, and the iconic American eagle symbol (which essentially acted as a third zero). This may be the version of roulette with the highest house edge in history, as single number bets paid 27-1 and there were 31 spots on the wheel. The house held a 9.68% advantage over players! Not surprisingly, this wheel would eventually fall out of fashion and the eagle was removed from the roulette wheel.
Eventually, the traditional French wheel – the one with two zeroes – made its way through New Orleans and into the United States, becoming the de facto standard there. Meanwhile, the German wheel became the one used in European casinos, leading to the situation today where both American and European roulette have been allowed to flourish in different parts of the world. Both of these wheels now feature 36 numbered pockets divided evenly between red and black colors, while the zeroes – one in European roulette, and two in American – are colored green.
Modern technology and the broadening of player tastes means we can expect to see some different styles of roulette wheels, be it online, digital or in a live casino. Recently Al Moe wrote about the Double Action Roulette Wheel by TCSJOHNHUXLEY, which features two sets of numbers on different rings, yet on the same wheel. It offers a whole world of new and exciting odds. We can expect to see more of these innovative designs in the future.
Roulette Wheel Layouts
Although it may be difficult to discern a pattern when you look at the numbers on a roulette wheel, it should be noted that they are not randomly distributed. Instead, a specific order of numbers is used at most casinos, beginning with the single zero and moving from there. However, the pattern is (necessarily) different between the single-zero and double-zero wheels.
In European single-zero games, the pattern of numbers is especially important, as certain bets (known as French bets) are commonly made that cover portions of the wheel. For instance, Voisins du zéro (neighbors of zero) covers the 17 numbers that surround the zero on the wheel, including the zero itself. Other French bets cover thirds of the wheel, such as the 12 numbers between 27 and 33 on the layout (including those two numbers).
The colors associated with each number are not random either and follow a fairly simply pattern. For the number ranges 1-10 and 19-28, odd numbers are red, while even numbers are black. Conversely, in the number ranges 11-18 and 29-36, odd numbers are black and even numbers are red.
European roulette wheel diagram.
A European (and French) roulette wheel consists of 37 slots, numbered from 0, 1 through 36.
Red and black numbers change.
In the arc to the right of the zero (numbers from 32 to 10) there are nine black numbers that are small (2, 4, 6, 8, 10, 11, 13, 15, 17) and nine red numbers that are big (19, 21, 23, 25, 27, 30, 32, 34, 36).
To the left of the zero (numbers 26 to 5) there are nine black numbers (20, 22, 24, 26, 28, 29, 31, 33, 35) and nine red numbers (1, 3, 5, 7, 9, 12, 14, 16, 18).
Numbers face the inside of the roulette wheels.
There are three standard arcs which are covered by call bets (announces):
“Voisins du Zero” Arc
Consists of twelve continuous numbers: 22, 18, 29, 7, 28, 12, 35, 3, 26, 0, 32, 15, 19, 4, 21, 2, 25.
The “Tier du Cylindre” Arc
Consists of the following numbers: 27, 13, 36, 11, 30, 8, 23, 10, 5, 24, 16, 33.
The “Orphans” and “Orphelins” Arc
The “Orphans” and “Orphelins” contains eight numbers: 17, 34, 6, 1, 20, 14, 31, 9.
American roulette wheel diagram
An American roulette wheel contains 38 slots. The difference between European and American roulette is that the latter has a double zero slot, all other slots are the same – zero and numbers from 1 to 36.
In American roulette the numbers on the roulette wheels are ordered in such a way as to achieve certain mathematical balance between red and black, high and low and even and odd:
Red and black numbers change each other.
Usually two odd numbers are in turns with two even numbers.
All red numbers are opposite black numbers.
Every odd number is opposite the next higher even number.
Zero and double zero are both green slots, while the remaining 36 are split between red and black.
Numbers face the outside of the wheel.
Biased Roulette Wheels
One of the most interesting aspects of roulette is the idea that sometimes a wheel may not be perfectly balanced. Whether because of a flaw in the creation of the wheel or due to damage accumulated from usage, some wheels may gradually begin to favor some numbers over others. If this bias is in any way significant, it is then possible for players to take advantage of this and hold an edge over the casino.
Players have been defeating biased wheels for well over a century, with famous instances of this occurring in 1873 and more recently in the 1990s. However, recent developments in wheel technology have made it far less likely for wheels to show significant bias.
Manufacturing standards have been improved to the point where wheels rarely show bias. Casinos are also able to constantly monitor their roulette wheels for signs that they might be developing any sort of bias. In addition, just in case bias appears that the casino fails to detect, many casinos rotate wheels from table to table, making it difficult (if not impossible) for players to keep accurate records of the result on any given roulette wheel. You can read more about biased wheels here.