A crossed roller bearing comprising: a plurality of rollers spaced around a three-hundred and sixty degree circumferential extent of the bearing, adjacent rollers being crossed such that the respective axes of the adjacent rollers are generally normal to one another; a plurality of spacers, one spacer of the plurality of spacers positioned between each adjacent roller; the crossed roller bearing being characterised by an odd, non-singular number of high-points positioned as near to evenly as possible about the circumferential extent of the bearing, the high-points defined by locations at which rollers with the largest diameters are positioned; an odd, non-singular number of low-points positioned as near to evenly as possible about the circumferential extent of the bearing, the low-points defined by locations at which rollers having the smallest diameters are positioned; wherein the odd, non-singular number of high-points is the same as the odd, non-singular number of low-points; or an even number of high-points greater than two positioned as near to evenly as possible about the circumferential extent of the bearing, the high-points defined by locations at which rollers with the largest diameters are positioned; an even number of low-points greater than two positioned as near to evenly as possible about the circumferential extent of the bearing, the low-points defined by locations at which rollers having the smallest diameters are positioned; wherein the even number of high-points is the same as the even number of low-points; wherein each low-point is positioned as near to evenly as possible between two adjacent high-points; wherein rollers of the plurality of rollers positioned between a high-point and a low-point decrease in diameter in a direction from the high-point to the low-point; and wherein each high-point is defined by a pair of rollers that ride on alternating races of the crossed roller bearing. a plurality of rollers spaced around a three-hundred and sixty degree circumferential extent of the bearing, adjacent rollers being crossed such that the respective axes of the adjacent rollers are generally normal to one another; a plurality of spacers, one spacer of the plurality of spacers positioned between each adjacent roller; an odd, non-singular number of high-points positioned as near to evenly as possible about the circumferential extent of the bearing, the high-points defined by locations at which rollers with the largest diameters are positioned; an odd, non-singular number of low-points positioned as near to evenly as possible about the circumferential extent of the bearing, the low-points defined by locations at which rollers having the smallest diameters are positioned; wherein the odd, non-singular number of high-points is the same as the odd, non-singular number of low-points; or an odd, non-singular number of low-points positioned as near to evenly as possible about the circumferential extent of the bearing, the low-points defined by locations at which rollers having the smallest diameters are positioned; wherein the odd, non-singular number of high-points is the same as the odd, non-singular number of low-points; or an even number of high-points greater than two positioned as near to evenly as possible about the circumferential extent of the bearing, the high-points defined by locations at which rollers with the largest diameters are positioned; an even number of low-points greater than two positioned as near to evenly as possible about the circumferential extent of the bearing, the low-points defined by locations at which rollers having the smallest diameters are positioned; wherein the even number of high-points is the same as the even number of low-points; wherein each low-point is positioned as near to evenly as possible between two adjacent high-points; wherein rollers of the plurality of rollers positioned between a high-point and a low-point decrease in diameter in a direction from the high-point to the low-point; and wherein each high-point is defined by a pair of rollers that ride on alternating races of the crossed roller bearing. an even number of low-points greater than two positioned as near to evenly as possible about the circumferential extent of the bearing, the low-points defined by locations at which rollers having the smallest diameters are positioned; wherein the even number of high-points is the same as the even number of low-points; wherein each low-point is positioned as near to evenly as possible between two adjacent high-points; wherein rollers of the plurality of rollers positioned between a high-point and a low-point decrease in diameter in a direction from the high-point to the low-point; and wherein each high-point is defined by a pair of rollers that ride on alternating races of the crossed roller bearing.