Longboard skateboard bearings and high quality ABEC5 . Made with the highest quality steel are ideal for skating in skate , longboard and cruiser .
Includes: Pack 8 bearings.
The ABEC rating includes categories (odd ) 1,3,5,7,9 and some years ago an American company began manufacturing ABEC 11 bearings .
Based on equal size and roundness of the balls and the alignment and perfection of the tracks following its creation and welding, precision is set . The higher the category are smaller tolerances , making the bearing more accurate .
High accuracy and low tolerances are required in applications where the bearings are rotated at speeds from 20 to 30,000 rpm until 300000 turns. Note that the bearing is on the shaft and a piece of size rotating at high rotation speed the kinetic energy increases in proportion to its velocity x 1/2masa velocity squared .
In such cases, a bearing ABEC 5 or 9 may be suitable .
But one skate with 70mm wheels turning 20,000 rpm would go to 263 km / h . In most cases skates not exceed 60 km / h , the bearings will at 6300 rpm ( in the worst case , with 50mm wheels traveling at 60 km / h ) and the most of the time they pass below 2500 rpm . So to speed skating at a skate needless precision but can receive heavy loads that can damage bearings in blows .
The dimensions and tolerances controlled by the ABEC standard include the diameters and widths of the raceways and some level of surface smoothness . The criteria as ABEC system ignores side loading , impact resistance , and material grade selection , lubrication, seals types of balls , space between balls and tracks, installation requirements and the need for maintenance and cleaning. All these points are important in the operation of a bearing , although not mentioned ABEC certification .
There may be a huge difference between running two bearings with ABEC same category . In fact many times a bearing with ABEC superior category can run worse than one of lower level when you put on a particular site . So based solely on the ABEC standard for the election of a bearing can be confusing to users who are not traders and manufacturers . The ABEC category is irrelevant if used as the sole selection criterion.
For maximum accuracy and minimum friction is reached using ceramic balls , which in turn greatly increase the fragility to shocks due to this, the ABEC standard is not synonymous with strength , if not just tolerance or accuracy.