Why would you rig a roulette wheel?

In old movies with a casino scene, there’s often dialogue or other cues that the roulette wheel is rigged.

Even single zero roulette has a high house advantage, it doesn’t make sense to ‘rig’ it.

Also, how (in general) would you rig it? Maybe if you can avoid the ball landing on a particular number would make sense, but that would only protect the casino against paying out those bets. The outer bets such as even/odd or red/black will still be paying off unless you rig it to always hit zero.

Maybe you might rig one to make it easier to win in order to lure in more players or bigger bets.

Just making it hit zero slightly more often would increase the house’s take, and, depending on how it was done, might be hard to detect, presumably.

As for why to risk it, greed, I suppose. But I have no idea how often it’s actually happened in real life. Particularly these days when gambling is so regulated.

A legitimate casino just depends on the house margin. But it isn’t a stretch to imagine some operators might like a little extra insurance against single big bet losses. Some high roller placing a couple of million on red might make the margins look a bit thin for the day. A little greed goes a long way.
The other reason that comes to mind is a casino involved in money laundering. An ability to control the flow of wins and losses might be designed in such a manner that the statistical flow of money matches expectations, and doesn’t attract attention, but does allow money to be directed between apparently unconnected punters. I doubt this is a real thing. But it isn’t beyond imagination.
Modern casinos maintain statistics on all plays, and work to ensure the wheels are fair. Simple mechanical issues can affect fairness, unevenness of the bars between numbers might make for a slight bias to some numbers over others.

All manner of amusing devices have been proposed. Magnets always attract attention. But say tiny air jets that are built into a wheel that can be used to reduce the likelihood of the ball landing in a number might work. Rigging only needs to skew the odds, it doesn’t need to overtly totally fix an outcome. Add little jets that make red slightly more likely than black, engage them when the table bets are both high and skewed one way.
In the extreme, just very slight differences in the geometry of the dividers between numbers might make the zero ever so slightly more likely. Or just place a weak magnet under the zero. Just enough to skew things. These would show up in statistical analysis, so would not pass muster in modern times. But a switch-able magnet that was only used when the table was loaded and say skewed an additional 10% chance of zero to the house might pass unnoticed, and nicely bolster earnings. A wheel that was made to make zero 10% less likely with no magnet, and 10% more likely with magnet could be controlled to pass simple statistical tests, but still return a useful little extra to the house. As always, the trick is to control the greed.

“Ah, Mister Balestreri, the owner saw that you were staying here tonight. He hopes you’ll enjoy the bottle of bubbly he’s having delivered to your room… and, he advises you try this roulette table here. Jocko’ll take good care of you and … ah, bet on twelve.”

Humphrey “ Rick” Bogart was very generous with his at Ricks Cafe !


I’m always suspicious when the dealer calls the “no more bets” too early. But my experiences with roulette are only in AC or Vegas, so probably little chance of rigging. That said, I seem to have luck by avoiding numbers with higher value chips of other players already on them.

Moving to the Game Room.

I think if the house rigs the wheel to land slightly more often on a particular number, or section of numbers, it means slightly more players would lose. By the same token, if a player somehow detects this they can take advantage of it.

Why? I assume people normally bet on the numbers equally.

This would inevitably occur, on the other hand. That’s how Joseph Jagger broke the bank in Monte Carlo in 1880.

In movies there often seems to be a pedal operated by the dealer (or whatever the operator is called) that lets him slow down or speed up the wheel. Besides making sure it lands on a number nobody has bet on, a rigged wheel can also be used to hustle a sucker. Let them win a couple and when they feel lucky and bet a wad, make sure they lose.

They could, but, as has been pointed out, there is zero incentive to do so. The house makes money hand over fist anyway, so why risk stiff penalties for blatant cheating?

But in the movies there is a specific mark. Take him to the cleaners and you have leverage to make him do stuff for you.

Someone, perhaps a MIT group did a project finding based roulette wheels and was able to make quite a bit before the casino’s found out and changed their procedure, Basically they were able to track numbers over several weeks and looked for any bias over the hose’s advantage. Using many members coming and going they were able to beat the house. Now the casinos check for bias and also rotate their wheels among the tables and back room making it hard to track what wheel is what.

Now I’m not sure. My assumption was that unless the players bet on the rigged number more than they otherwise would, the house would come out slightly ahead by this scheme. Obviously, this only works for the house if none of the players pick up on the wheel being rigged, so it would be another one of those capers like stealing a penny out of fifty million bank accounts.

But I wouldn’t be surprised if this is a far more complicated problem in probability theory than I could hope to handle.

This is the book about that particular caper. I recall reading it in the 80’s

12 had better pay off, or some of the Balestreris that I’m aware of will be very unhappy.

The Balestreris also make some great pizza

Part of my job as a casino pit boss in Las Vegas was occasionally moving the roulette wheels around to different locations, swapping one to the back room, out of play, and regularly leveling the wheels by adjusting the legs. I never heard anything about rigged wheels in Nevada.

For a short time (a long time ago) I was involved with a small group of people with a roulette computer; we never operated in Nevada. The computer was custom made by an electronics wizard on a lark just to see if he could do it; he only made six of them, keeping one for himself and selling the others.

One player had several switches on his body used to time the speed of the wheel head and mark the location where the ball dropped out of the track. The idea was to detect tilt. Once a wheel with tilt was detected the BP (Big Player) was called in. An earpiece told him which section of the wheel would be under the spot where the ball would leave the track; BP had trained to very quickly place some bets on the area following that section once the proper timing was achieved. Tilt could sometimes be achieved by someone leaning on the wheel.

Our advantage was at least 17%, often higher depending on conditions. One BP freaked out and left, muttering “This is too strong. We’re gonna get in trouble.” This was the time period when the dealer calling out “No more bets.” became common when a European casino became aware of one of the devices.

The guy who bought the computer and his girlfriend were caught coming into customs in Florida with several bogus passports and spent some time in prison and then was confined to FL for a time while on parole. The computer was never questioned by customs; it was just a black box that did nothing unless the software for it was loaded into the device via a modem – otherwise the earpiece would only squawk “I’m dumb.”

I quit the group when our BP was heard talking to someone in Nevada about our device and naming the inventor.

I’ll repeat that we never used or even possessed the device in the state of Nevada; all trips were offshore … and anyway, it was a long time ago.