In theory, at least, every roulette wheel in operation in casinos across the world should be perfect: that is, it should deliver perfectly random and unpredictable results with each and every spin.
That way, the casino can protect their house edge and players know that each spin of the wheel is statistically likely to be different from the last.
Perfect, right?
That’s the theory. But in reality, there are roulette wheels that are less than perfect – and which yield slightly more predictable results, therefore shifting the house’s edge in the player’s favour.
But how common is wheel bias in roulette? How do you find biased wheels and who has taken advantage of the situation the best in the past?
What is Wheel Bias in Roulette?
A roulette wheel can have mechanical imperfections that alter the manner in which it spins, most commonly an error in its balancing.
Many casinos still use roulette wheels manufactured years ago, and while these are simplistic in their design, there’s still plenty of moving parts that can become defective over time. If a wheel doesn’t spin perfectly, has a ‘dead’ spot or slows at particular times in its rotation, common patterns of numbers can be identified as occurring above the expected frequency.
This is a mundane example, but think of a flat-roofed building after a heavy rain shower. Why does the water pool in certain places? Because there’s an imperfection in the roof, i.e. it’s not perfectly flat or has some kind of dink in it. A similar mechanical failure in a roulette wheel will result in a similar phenomenon.
The outcome is that savvy players can identify the bias and then bet accordingly based upon the results of previous spins – be it by backing specific numbers or perhaps a set of three or four numbers that have a higher probability of being spun.
Identifying wheel bias in roulette requires you to manually record the outcome of thousands of spins – the laws of large numbers and variance dictate that if you spot a pattern with just a few spins, that could just be randomness rather than a bias/defect in the wheel.
How to Exploit Wheel Bias in Roulette
One of the difficulties in exploiting wheel bias in roulette is that you will have to record the results of a number of spins before a pattern can be identified. Clearly, if a casino catches you sat by the table with a pen and paper not betting, they are going to get suspicious and probably ask you to leave.
So you are going to have to log the results in your mind, and ensure that your sample size is large enough to be of relevance – we’re talking hundreds of spins, rather than a small handful, to identify the intricacies of a biased wheel.
All of which means that exploiting a wheel bias in roulette takes time and patience, so you’ll need a sizable dose of both to really make this work. You may even need to employ a small team to continue logging results when you’re not able to.
After you’ve collated enough data, you may just notice a detectable pattern in how the wheel spins and where the ball lands. On a standard European roulette wheel, there’s a 2.7% chance of any of the 37 numbers landing with any spin – if your results show that some numbers, or more likely a group of numbers located next to each other on the wheel, are spun more than this, you may just have uncovered a biased wheel.
By betting on specific numbers or a particular quadrant of the wheel, you can utilise the bias to increase your win probability by the percentage above 2.7% that you expect the number(s) to be spun.
But there is a word of caution to be had: by betting on the same number(s) with every spin, you may give the game away that you have spotted a flaw in the wheel.
Of course, superstitious players will bet on the same number all the time – maybe a lucky number, a birthday or so on. But are they winning more often than they should be, probabilistically speaking? They may be, but that’s a rare occurrence.
Casino croupiers and dealers are trained to spot chinks in their employer’s armour, so if you are winning with some regularity with the same individual or groups of numbers, you may be outed. That’s why betting occasionally on other numbers, groups or call bets – just to throw the house off the scent – is a necessary cost of taking advantage of roulette wheel bias.
Who Has Exploited Wheel Bias in Roulette?
You may not be surprised to learn that those that have ‘clocked’ a biased roulette wheel are not too keen to give away their position publicly!
There is the potential to profit from a skewed roulette wheel for weeks or even months, so you won’t find too many that have gained an edge in this way revealing their wheel of choice.
But there are three high-profile instances in which a biased roulette wheel has been taken advantage of, and the first took place way back in the 1800s!
The enterprising Joseph Jagger, thought to be a distant relative of Rolling Stones singer Mick, did exactly as we have outlined in this article: he employed six assistants to record the results of the half-dozen roulette wheels in the Beaux-Arts Casino in Monte Carlo around 1873.
After analysing the data, Jagger found that one of the wheels showed a bias towards a group of nine numbers – not a perfect scenario, but one that he was able to exploit nonetheless.
And exploit it he did. Jagger made around £65,000 from the dodgy wheel before the casino removed it from the gaming floor – adjusted for inflation, that’s about £7.5 million in today’s money.
You may have heard the name Billy Walters before; he’s one of the most prominent professional sports bettors in America.
He invested heavily in computers and data back in the 1980s before few others were, and in forming his own ‘Computer Group’ he set to work crunching the numbers of the results of roulette wheels from across Atlantic City.
After collating enough data, Walters and co found that one wheel in Atlantic City DID have a bias towards a specific section – the numbers 7, 10, 20, 27 and 36 came up more often that they probabilistically should have done.
Following two days of almost uninterrupted play at the wheel, Walters walked away around £3 million richer.
One case of roulette wheel bias almost led to the intrepid player in question facing criminal charges, however the courts would eventually come down on the side of Gonzalo Garcia-Pelayo.
He had found a bias in a wheel at the Casino de Madrid following months of painstaking data collection, and from 1991 he started grinding out profitable gaming sessions. Within a year Garcia-Pelayo, assisted by members of his family, had accrued winnings in the region of £700,000.
After finding out and suing Garcia-Pelayo in a case that went all the way to the Supreme Court of Spain, the casino was dismayed that the judge came down on the side of the player – adjudging that he had done nothing to manipulate the outcome of each spin, and had instead merely observed what was unfolding beyond his control.
Allowed to keep his winnings, Garcia-Pelayo upped sticks and moved to Las Vegas….where he won more than £1.5 million playing roulette.