Roller Skate Bearings

Roller skate bearings come in many different types. Original roller bearings were loose and would sit in a "cup" around the center of the skate wheel. Many problems arose from this type of bearing, the biggest being when a wheel would loosen the ball bearings would fall out everywhere. Since the Loose Ball Bearings were incredibly hard to maintain, precision bearing were developed that encase the balls in a track that allowed for a more smooth roll. Precision bearings are now the bearing of choice among all skaters - Inline, Skate Boarders, Derby Skaters, and Artistic and Speed Skaters. 

Roller Skate Bearings are made from steel and have different sizes associated with them. Some of the precision bearings have 7 balls inside the race and others have 8. The difference being the size that allows for less friction inside. The center of the bearing or the shaft size are typically 7mm or 8mm. This determines what size axel they will fit. There is no difference between the 7mm or 8mm bearing by manufacture other than the center opening.

ABEC (American Bearing engineering Committee) is a rating given to the bearings by the industry to determine the tolerance. The higher the rating the better precision of bearing but does necessarily mean more speed. The typical ratings are 1, 3, 5, 7, and 9. A bearing that does not conform to at least an ABEC 1 is not considered to be a precision bearing. The higher rated bearings are design for real precision applications and the lower ratings are more for skates, skateboards, fishing reels, or industrial machinery. You can certainly use a higher rated bearing in any skate but understand it is not going to make a faster skater. None of the ratings take in to account the smoothness of roll, ball precision (shape), or the quality of steel used. So it is best to choose a well made bearing not necessarily a High Rated Bearing. No human alive can make a bearing go as fast as the testing machines!!