Abstract: A method, comprising recording the number of rotations of a first bearing race in relation to a second bearing race in a roller bearing, recording counts of at least one indicator, wherein at least one indicator indicates a revolutions of a plurality of rolling elements about the second bearing race, calculating a ratio between the recorded counts of the at least one indicator with a recorded number of revolutions of the first bearing race, comparing the calculated ratios with a corresponding ideal value for the ratio, wherein the corresponding ideal value is determined without friction fit-induced slip, determining a difference in the comparison, and outputting the difference as an average friction fit-induced slip for the plurality of rolling elements.