gotcha. So the more skit patches a gearing setup has, the more likely you are to spread the wear out over different places on the tire when you do skids based on a skid patch being selected somewhat at random based on where the drivetrain was when the rider locked it up.

That would be really easy to add in if someone knows the formula. I think you could do it the hard way by calculating the angle that the rear wheel turns with 360 degrees of crank rotation. If you keep adding this number up until you reach an even multiple of 360, the number of times you added it together should theoretically be the number of possible skid patterns. Does this sound right?