Ready to learn the mysterious ways of the roulette wheel and become the world’s biggest roulette nerd? Let’s kick off with the wheel itself and learn what makes this marvellous machine tick.

What is a roulette wheel?

The word roulette means ‘little wheel’ in French. The wheel is basically a way to use the laws of physics to pick a random number. The game sends a ball hurtling round the edge of the wheel and as the ball decelerates, it drops down into the ring of numbers and a few zigs & sags later, lands in a pocket.

A roulette wheel is a complex mix of carefully calibrated parts, dressed up to the nines for its night out at the casino! Manufacturers combine quality craftsmanship with cutting edge technology to ensure wheels look a million dollars and deliver high performance for operator and punters alike.

A roulette wheel is made up of a base sat on a metal spindle and bearings so it can move smoothly with virtually no friction. The conical bowl allows the ball to spiral down towards numbered pockets which line the wheelhead. Finally, a turret sits in the centre for decoration.

Although smaller wheels do exist, most standard size wheels are 80cm across. They’re usually made from a combination of woods or plastics along with steel, aluminium or nickel to add a shiny finish. Depending on how posh your casino is, you might see mahogany, walnut or rosewood veneers used as to complete the wheel.

Secret #1

Fancy a game at home? Roulette wheels can cost well over £10,000 although casino cast-offs occasionally pop up on eBay for around £2,000. Too pricey for the ultimate home accessory?

Making the predictable unpredictable

Not everything on a wheel is there for decoration. Conjuring up the randomness that makes roulette so exciting, and there are a few areas of the wheel responsible for making the magic happen.

Separator rings between pockets vary from high to low profile and come in straight, curved or scalloped designs, creating a variety of ball patterns. Ball stops or diamonds are metal deflectors set into the ring above the numbers, designed to maximise what the makers call ‘ball scatter’, an uneven bounce which makes it even harder to predict the outcome.

Avoiding any bias which could produce patterns eagle-eyed players could exploit is the number one job for manufacturers. Wheels are now so precisely engineered that they’re immune to changes in temperature and even humidity. The latest wheels are made from plastic with tracks made using epoxy resins to prevent cracks or wear, and to extend the life of a wheel. Automated wheels include random rotor speeds to combat ‘clockers’ who measure wheel and ball speeds to try and predict where the ball will land.

Secret #2

The world’s leading roulette wheel manufacturers, Cammegh and John Huxley, are both based in the UK.

Roulette wheels do one job, and that’s provide us with a string of random numbers, but they’re not much use without a betting layout. You’ll find the betting table next to the wheel, usually made of felt. All of the numbers on the wheel are set out in 3 columns with a zero taking pride of place at the end. You can place bets on single numbers, splits, columns and even money bets, all with just a single bet. The bet types and their payouts are the most important part of the game when you learn how to play roulette.

Numbers and layouts

There are 37 or 38 numbers depending on the type of game you play, from 0 to 36. Aside from the green zero, which gives the house its edge, half of the numbers are red and half black, and they alternate red-black-red-black and so on around the wheel.

As you go round the wheel, you won’t see numbers increase by 1 each time either. For some unknown reason, all roulette wheel layouts feature numbers in a seemingly random order. Roulette players can often tell you which numbers come immediately before and after their favourite, though rarely can they guess the order of any other sections.

Play roulette online and you’ll have a choice of European, French or American roulette, and it may not be instantly obvious they’re different. The key is in that special green number which helps give the house its edge, but it’s not the only difference.

Secret #3

Black 17 is the most popular roulette number, much loved by James Bond and billionaire Mike Ashley, known for his million-pound winning streaks.

When comparing American vs European vs French roulette wheels, it’s important to know how the numbers change and what effect that has on the house edge.

European roulette wheels

On European roulette wheels and French roulette wheels, alternating red and black numbers are joined by a single green zero, which gives players the lowest possible house edge of around 3%.

French roulette terms are essentially the same except for a unique rule called La Partage, which gives you half your stake back if you place an even money bet and zero comes in. That rule along helps to reduce the overall French roulette house edge to just 1.35% for even money bets.

0 – 26 – 3 – 35 – 12 – 28 – 7 – 29 – 18 – 22 – 9 – 31 – 14 – 20 – 1 – 33 – 16 – 24 – 5 – 10 – 23 – 8 – 30 – 11 – 36 – 13 – 27 – 6 – 34 – 17 – 25 – 2 – 21 – 4 – 19 – 15 – 32.

This way of organising numbers also has an effect on the roulette table, where the various bets are displayed.

Secret #4

The game is sometimes called The Devil’s Wheel’. Why? The numbers on the wheel add up to 666!

American roulette wheels

On American wheels, the wheelhead has extra room for a second zero called 00, which lives on the opposite side of the wheel. Although American roulette has an extra betting opportunity, double zero brings the house edge down to 95%.

American wheels also use a totally different roulette wheel sequences of numbers too, just to be different!

0 – 2 – 14 – 35 – 23 – 4 – 16 – 33 – 21 – 6 – 18 – 31 – 19 – 8 – 12 – 29 – 25 – 10 – 27 – 00 – 1 – 13 – 36 – 24 – 3 – 15 – 34 – 22 – 5 – 17 – 32 – 20 – 7 – 11 – 30 – 26 – 9 – 28.

Secret #5

Early roulette wheels in the US also had an ‘eagle’ pocket which players couldn’t bet on. If the ball landed in the eagle, it counted as a win for the house. Definitely not OJO-Fair!

The roulette ball

A wheel’s not much use without its little white friend! In the early days of the game, roulette balls were originally made of ivory. That wouldn’t’ fly these days of course, so they’re now made from synthetic materials like nylon, Ivorine and Teflon. To ensure they stand out against the dark colours of the wheel, roulette balls are always white or cream. The one thing a ball is born to do is roll evenly, so they must be perfectly spherical.

They also need to be sized to fit the track, and are usually around 18 to 22mm in diameter, about the size of a grape. The material used to make a ball has a big impact on its weight and the way it behaves on its travels towards the pockets, and the varying types of ball makes it even harder for clockers to predict where it will fall.

Croupiers will usually aim to spin the ball between 10 and 20 times around the wheel, and launch the ball from the same point on the wheel, often using the zero as the marker. Ball bounce is an essential part of the unpredictability of roulette, which is one of the reasons why croupiers release the ball in the opposite direction to the wheel spin. A ball travelling clockwise colliding with a pocket travelling the other way will be far more exciting to watch, and produce more variation in results too.

Automated roulette

Casinos can’t increase the house edge without upsetting their punters, and it’s hard to fit more, so the only way to boost your roulette revenue is by squeezing more games in per hour. That’s where automatic roulette wheels come in.


A roulette wheel that runs itself, linked to electronic betting terminals? It’s the stuff pit boss dreams are made of! With no croupier, no physical bets to pay out, automatic wheels can deliver many more spins (up to 100 spins per hour, much more than the 30-40 spins per hour using a croupier) and in a more controlled way.

Secret #6

The machine keeps up to 10 balls ready to go and can switch between them at random.

Automated wheels use a variety of techniques to recreate the job of the croupier, report the numbers and connect to the betting terminals. The ball is launched using air pressure and a mechanical device in the bowels of the beast tracks and randomly adjusts the speed of the rotor. Once the ball has landed, sensors in the walls of the wheel determine the lucky number and inform the software running the various screens players use to play.

Online roulette wheels

Now we’re talkin’! No wear and tear at OJO’s online casino. Although they’re inspired by their wooden forefathers, online roulette wheels are animations created by graphic designers and hooked up to computer software. Instead of Newton’s laws of motion, randomness is produced by mathematical algorithms called Random Number Generators or RNGs. When you play online roulette, you get the same results as you would in Live Roulette or in a real casino, but with even more spins per hour than an automated wheel.

Let’s get back to the real thing…

How roulette wheels are used

A roulette game starts and finishes with a wheel at rest, but there’s plenty of drama in between! The croupier stands next to the wheel and spins the wheel clockwise, then sends the ball in the opposite direction on a track above the numbered ring.


As the ball spins on its track, the croupier will announce ‘no more bets’ and you’ve got a few seconds left to get your chips on the table. As the ball loses speed, it drops into the main barrel of the wheel, spirals down the cone and catches the edge of a pocket. This is where the fun happens, as the ball bounces in and out of the numbers on a roulette wheel before finally choosing its home.

Secret #7

Croupiers switch balls regularly, stashing the spare on top of the turret. The croupiers also switch between different sizes of ball to vary the speed of slow-down.

Croupiers receive training in how to use casino roulette wheels which includes spinning the ball at a variety of speeds to increase the unpredictability. Rumour has it, pit bosses ask croupiers to spin the ball faster – and therefore for longer – during busy times to give punters the chance to place more bets, and then slower – so the ball drops more quickly – at quieter times to get more games in.

How do casinos guarantee roulette wheels are fair?

Roulette is big business for casinos, so the companies that manufacture and install wheels have to get it spot on. Gaming regulations often state the precise dimensions, weight and other specifications of roulette equipment, though it’s not impossible for biases to appear as a result of wear or defects.

Secret #8

Even if you find a wheel you suspect is biased, it can take over 4,000 spins to be sure a bias exists.

Bias is actually great news for some players who travel far and wide in search of biased wheels which display predictable patterns. The quality of engineering and technology has effectively eliminated these opportunities and you can bet your bottom dollar that casinos are tracking every number on every wheel to ensure the outcomes are truly random.

Who invented the roulette wheel?

Roulette was invented around the end of the 18th century in France, although it borrowed certain features from all sorts of European parlour games including a ball-and-top game called Roly Poly. French scientist Blaise Pascal is considered the inventor of the modern roulette wheel, but he didn’t have gambling in mind. He tried and failed to create a perpetual motion machine – a device which could spin indefinitely without any outside help – but added a legendary gambling game to his legacy instead! Let’s hope he made some money out of it.

Famous attempts to beat the wheel

There are countless tales of ‘clockers’ spotting wheel biases and taking down the house, not least medical professor Richard Jarecki who tracked biases in wheels across the world with his wife and won $1 million in the 1960s.

Secret #9

UK gambler Ashley Revell sold his house and all of his possessions to bet the lot on red. He eventually found a Vegas casino that would take his bet and lucky for him, red 7 came in to net him $270,000! Not exactly what we’d called safer gambling, but hey.

But the most fascinating roulette tale starts with the father of card counting, Edward O. Thorp, who invented his own wearable roulette computer to measure the speed of wheels and balls.

He then inspired a team of mathematicians who used devices concealed in shoes to measure wheel and ball speed. They communicated that data to another person who computed the likely section of numbers to bet on and passed that info via an earpiece to the bettor on the gaming floor. Called the Eudaemons, the notorious group had some success, earning over $10,000, but had a few bumps in the road too. Computers were crude and occasionally caught fire, singing a few toes in the process!

Daniel Grant

Dan Grant has been writing about gambling for 15 years, and been fascinated by beating the odds for even longer. Now he’s on a mission to help others bet smarter and avoid the mistakes he made. When he’s not obsessing over bankroll strategy or counting cards badly, he’s hosting The OJO Show podcast.

Share this article