Intro to Biased Wheels--- Part 2


Based on my Studies- - I see that many different defects, or a combination of events, could cause biased-wheel sectors and/or pockets.


  1. slightly bent central spindle
  2. warped wheel head
    3 unevenly worn ball tracks
  3. tilted Wheel
  4. Balls that are not perfectly rounded
  5. Balls that are not perfectly balanced
    certain temperatures
  6. certain rotor speeds
  7. certain times of the day
  8. dusty wheel
  9. someone leaning against the table
  10. air pressure
  11. worn down pocket not noticeable by the human eye
  12. scratches on the rotor

It can get very cumbersome trying to keep track of all the potential variables that may influence the data and the conditions surrounding these variables. BUT THE BOTTOM LINE IS, It’s possible one wheel can be influenced by several of these factors listed above in such a way that such a biased wheel can go undetected for months, even years.

Me personally, I would never sit through 10 thousand or not even 5 thousand spins. I THINK IT’S TOTALLY REDICULOUS TO JUST RANDOMLY PICK A WHEEL AND SPEND 2 MONTHS TESTING IT FOR 10 THOUSAND SPINS,

I believe in the main theory "that the way a certain ball scatters on a certain wheel - - based on a certain wheel speed- - hitting the rotor at a certain angle - --will leave behind certain clues - - -. Not only that, but a possible bias that can be narrowed down from 1 to 3 numbers on that subject wheel.

The reason why 5 thousand to 10 thousand spins are needed for a biased wheel attacker is because they have to test all 37 or 38 numbers. Me on the other hand, If I have all ready limited my target area to 1 or 2 nuumbers - - LETS SAY 1 NUMBER FOR THIS ARGUMENT- - than I will finish my testing 37 times faster, since I do not have to test the other 36 numbers. WHICH MEANS MY BIASED WHEEL TESTING WILL BE ON THE AVERAGE OF 37 TIME FASTER THAN THE ATTACKER THAT HAS TO COLLECT A STUDY OF 5000 SPINS


so the formula is

(1 number being tested) times (135 spins)= 135 spins needed

however if I had to test all 37 numbers, we use this formula

(37 numbers) times ( 135 spins) = 4995 spins needed to properly test for a biased wheel with all 37 numbers.

Since 80 to 85% of all biased are tied directly to the rotor, it would make a lot of since to first pinpoint a possible problem area on the rotor, than run a biased wheel test for that particular section or number. that way, you could be all done the biased test in a fast as 135 spins, INSTEAD OF HAVING TO SIT OR STAND THROUGH 5000 SPINS.

PERSONALLY, I JUST THINK IT’S VERY STUPID TO JUST WALK UP TO A WHEEL AND RANDOMLY START TESTING ALL 37 NUMBER WITH NO PRIOR KNOWLEDGE OR EVIDENCE. that would take atleast 250 hours, or just over 1 month to complete working at it 8 hours a day.

It wouldn’t work in a real casino environment, since the wheel maintenance crew would have changes the dynamics on that wheel, once they are done rotating the wheel. However, the way I 'm talking about, if someone is good enough to locate a possible wheel biased to a certain pocket, AND JUST NEED TO TEST IF TO SEE IF THEY ARE RIGHT OR WRONG - - -than only 135 rolls are needed for the entire study for just that 1 pocket- - - too see if the tests hold up.

I know that those will argue with me, that its impossible to test 1 single for number for bias in only 135 spins. the fact is, if one gets effIcient enough to just become a scatter expert, and just watch the same wheel to locate a single pocket bias, IT’S POSSIBLE THEY BECOME SO EFFICIENT AT IT THAT THEY DO NOT EVEN NEED TO PROCEED TO STEP 2- - - WHICH IS TEST THAT SINGLE NUMBER FOR BIAS - - BECAUSE IF WE ALL READY KNOW THE BALL WILL GO either +8 OR -8 POCKETS FORM THAT TARGET NUMBER after it bounces from that particular angle, WE WOULD JUST PLAY ALL 17 NUMBERS BASED ON A CERTAIN WHEEL SPEED ONLY - - and just be a spectator if the wheel speed is to fast or to slow which would alter the way the ball bounces in that particular angle we are looking for.

Another slick maneuver is to just walk around a casino and find a rotor with unusual scratch marks ON THE ROTOR - - the question is how did those scratch marks get there? It could be from several reasons. remember, it takes a lot of force to put a scratch a piece of metal. A force great enough to cause a possible Bias worth looking into. The wheel could have been tampered with, dropped, or just a sign that it’s getting worn out based on the scratch marks. You never know until you run a preliminary test, or do like me - - see if the ball reacts a certain way during the scatter process, whenever it comes or bounces near the scratch marks on the rotor.

The kind of SH_ _ I’m telling you, you won’t find in a biased wheel book anywhere on the market - - because I believe those books just have general stuff in it you can find anywhere online. I ALSO BELIEVE THAT NO EXPERT ACTUALLY TELLS YOU EVERYTHING THEY KNOW. NOT EVERYTHING… THEY TEND TO KEEP THEIR BEST WORK AND SECRETS TO THEMSELVES. :wink:


There can be many reasons for a scratch on the rotor but if you have ever lifted one off the spindle, you will know that its extremely heavy for its size. Sort of “massive”. You can easyli do some damage in the process. To the spindle or the rotor itself, its usually perfect from the industri, but becomes bias during maintenance.

You are correct on many of the reasons, in fact, i have a feeling you got some sort of scipt or bias report lying around :D.

As you point out its important to spot the bias first, then classify the biases and marks on the rotor so the rotor can be identified even if they rotate the number ring, but leaves the rotor in the wheel after that. Takes 4 minutes for a experienced maintenance man maybe less.

You then classify the numbers as main or secondary biases. Some can right away be classified as receivers (positive bias)…(, and there will of course come a negative bias along. usually at some of the neighbour numbers or sectors).

The casinos arent actually very good at spotting a bias as some players are, but they got some very special equipment instead to make up for it. Personally i had been staring in the wheel for some 4 years without spotting 1 single bias because i didnt know how to spot it. I was at a point a couple of years ago fortunate to be contacted by the leader of a crew (biasplayer on GG) and play with them for a couple of months. I learned more in those months than i had learned from the scripts of Scott and Basieux all together. I just wished i had had a certain script from mr snow BEFORE i joined the crew. How they spotted the bias and employed trackers to follow the rotors day after day and how they “sold” a wheel in Holland where the alternative, to play it by themselfes, could have beed very damaging for their health. How they entered VB into the biased wheel with some devastating wins to follow. Absoloutely amazing.

My personal victory were when i passed + 3SD after 2100 placed bets with the crew and BP came and shook my hand and said “well done”.

  1. slightly bent central spindle
  2. warped wheel head
    3 unevenly worn ball tracks
  3. tilted Wheel
  4. Balls that are not perfectly rounded
  5. Balls that are not perfectly balanced
    certain temperatures
  6. certain rotor speeds
  7. certain times of the day
  8. dusty wheel
  9. someone leaning against the table
  10. air pressure

All above how it can effect result to be biased?
For example, 3 unevenly worn ball tracks.
It is pointless if you do not know rotor position at the time of ball exit.

  1. Balls that are not perfectly rounded
    It will effect prediction but it will not cause results to be more at one place then at the other one.

Tilted wheel/ or rotor
It is same, there is no advantage if we do not know exit point.
If rotor has tilt it is at one position but numbers are changing, therefore if we do not know which number will be at lowest position when the ball exiting and where it will exit there is not much use of it.

8,9,10,11,12,13 this may effect prediction but it will not produce advantage

  1. worn down pocket not noticeable by the human eye
  2. scratches on the rotor
  3. wobbled rotor

14,15,16 Yes

Correct me if I am wrong


That sounds 100% correct,

I forgot to mention a wobbled rotor. that’s a biased wheel attacker dream.

However, the only problem is that any roulette wheel maintainance team with half a brain should be able to easily spot a wobbled wheel using just their standard testing equipment.

The good news is that maybe it takes the casino a month or so between maintaince - - and a biased wheel attacker who was monitoring that particular wheel all along could do some serious damage over that month - - and actually get rich off that 1 casino blunder - – considered the casino fails to react and fix the wheel a lot sooner.

After that player smacks that casino around for 3 or 4 days, the casino will most likely react with their own little sneaky tactics. Even a complete dummy isn’t going to just sit back and watch a player take them to the cleaners for millions over that month gap between wheel maintanaince - - without taking some type of counter measure of their own. ;D


hi all members. First of all, sorry for my bad english, i am spanish.
Well, i have take a lot of numbers of a huxley traditional wheel.
there are 3 pockets that could be biased.
33 29 and 19

Yesterday casino changed ball. and numbers not appear. but yes the neighbours…
Could a change of ball affect to the bias??? they changed for a minor ball…and now the biased are other pockets

someone know something about that???
i need your help.
Thanks for all


try chat with Snownam on shout box


Its hard to tell on so little information.

  1. Is there any marks on the rotor ? (Is it possible to check if the number ring has been turned)

  2. The ball CAN change the bias slightly, depending on bias type and scatter type for the balls involved.

  3. The bias might still be there, biased numbers also sleeps. Try to run a number strenght test.

  4. Has there been maintenance ? Check for polish and clean hoovered pockets.

  5. Alternatively, send me the numbers and i will run them on my tools, including the number strenght test.


thanks kelly for all.
after to run the test for all numbers the profit that there are in each pockets is about 4% for each number. the casino mean for pockets if wheel arent biased should be about 2,7%. We have 3 pocket with marks than can be recognized easily. They never turn the ring because it will be very obiously. At all the statics of numbers, we oonly have a session that numbers have down extremely. The days that casino change ball (for a minor) onften appears more the neighbour that the biased pocket.
What do you think kelly?
If you want i can pass you all numbers recollected.
Thank for all



If it is pretty straight forward and obvious, i would suggest to split the normal bet size in half and cover 6 numbers whenever they use the small ball. You will win less, but you will be “at the ball” so to speak and not be missing out on the hits.

If you send me the numbers, i can run them on some exels, where there are some nice graphics and and also gives a very good picture on where the bias and antibias/donator numbers are located. It might help you spot where the actual bias is located. Sometimes the bias is located in the pockets where there are LESS hits than expected and the neighbour numbers that appears to have the bias is simply receiving hits from the neighbours. So the casino might try to repair the pockets that stands out positive in the standard deviation, where they should be looking somewhere else.

You can send the spins to


thanks kelly i have send you an email



It does not appear to be extremely biased, in fact it MIGHT be random. Chi Square is 55 which is the industrys benchmark for a bias, but in this case im not sure. If the spins had been seperated in clock and anticlockwise spins, it might have been clearer what was triggering the 2.9 SD at 19.

2.9 SD is not unusual for a 1500 spin sample. The number strenght test shows that up to 460 the hit rate pr 500 spins is 14 - 16 but then from there it soars up to 24 pr. 500. (expectation ~13.51) So if you know what happened at around spin 460 and forwards you might have an idea what caused the bias. Also you might wanna listen to the sound when the ball hits the pocket.

What insert material is in the pocket ?


Data zoomed up

Note that no 19 has 58 hits and the expectation is 39.95 and the break even is 41.06



hi kelly
very very good work, very thanks for all i will take more spins. we will send you. thanks for all the work.


This might be a stupid question, but is this data simply winning numbers? It’s not a scatter distribution or offset between winning number and any referens point on the wheel such as where the croupier spun the ball or where the ball had a certain speed or something like that?

In that case I’m surprised to see such a bias! Just 1/46 that this bias appeared by chance. Just hope that the bias remains over time.


Its just winning numbers. The sheet has a feature where you ALSO can enter the strike number on the rotor. Sometimes it can give you an idea which numbers are donating and which is receiving because it will show you which numbers has what kind of bounce in case there is a pocket bias with a loose fret that absorbes the ball force. This feature hasn`t been used since i only got the outcome numbers,

Chi Square is 55 and is on the line for a biased wheel, the danger here is that the numbers aren`t collected over a few days but over a longer period with breaks in it.


Manuelon have many spins have you clocked/recorded?


Well, I’m surprised!

But to gamble on this, I’d suggest trying to find out what physical defect is causing the bias. And of course combine it with VB or computer.

Maybe one of the croupiers i question has the habit of spinning the ball from where the zero is on the rotor? In combination with regular spin lengths and a drop zone, I could rationalize such bias.

I read somewhere that “in Europe” croupiers normally must start spinning the ball from the last winning number. That might create som kind of pattern if there is a drop zone, although that is unlikely to be strong enough to be detected.

The sheet has a feature where you ALSO can enter the strike number on the rotor.
Yes, I've actually already started to reverse engineer your spreadsheet with that purpose! ;D

I get a chi2 of about 53, but I guess that you calculate it on money return, I calculate it for raw winning number data. Or I’ve made som mistake. Looking into it…

Chi Square is 55 and is on the line for a biased wheel, the danger here is that the numbers aren`t collected over a few days but over a longer period with breaks in it.
55 corresponds to a 1/46.61 likelyhood that the bias occured by chance on an unbiased wheel, right? That's like 2.1% (or 97.9%). I'd say that's pretty convincing! It's very good you check the consistency over time too. I remember about non-parametric and other tests for that from school. I'll take this opportunity to refresh such know-how. While I've difficulties believing in the feasability of predicting roulette BEFORE the ball is spun, I'll focus on scatter analysis though.

Btw, aren’t history of winning numbers available for the public from many casinos? I mean, that they will give you a printout if you ask for it.


Well, the correct way of looking for a biased wheel is to find the bias first, map out which numbers is gonna stick out (you might not know up front wether they will stick out positive or negative) and then collect numbers. If your predicted biased numbers also confirms, even after short terms, to be biased, it is much more valuable than just a number that sticks out with ~ 3 SD and might be gone after another 200 spins.

Im trying to get as much info as i can on the wheel at the moment and there ARE some defects at some strategig good places. But i havent seen the wheel, so its a tough task since actually spotting a bias is quite tricky if you dont know how and WHAT to look for, and i can`t do that very well on e mail basis.

I suggested they took another 800 spins and seperated them in clock and anticlockwise spins, and i also asked for some specifics on the pockets and also a little bit on the rotor. With that info i can do a visual map of the wheel, (as good as it gets without actually seeing it) maybe mr snow will give his 2 cents too, and maybe in the end we can have a idea of what is happening in the wheel.

I didnt fabricate the sheet myself, so i gotta say i havent looked closer in the cell formula for the Chi. I can send you the cell formula for the Chi Square if its any help. But i think you are right, it will be in the money returned. The difference sounds plausible.

PS: Yes you can get the numbers in most larger european casinos, but its far better to collect them by yourself because you can then seperate them in clock and anticlock spins. You can`t trust that by just taking the numbers off the sheet. Some pocket biases is very sensible in wheel direction.

PPS: For some time i took numbers off Casino Berlin and Casino Bremen and Wiesbaden from the internet as they appeared. But it doesn`t cut it well enough. There is simply not enough info in the raw numbers alone. The bias NEEDS to be verified visually and the spin direction too.