BEARINGS : Bearings are the round metal pieces, that allow your wheels to roll, y determine how fast and smoothly they rotate. A skateboard requires 8 bearings, 2 for each wheel. There are 2 types of bearings, steel and ceramic.
Steel or Ceramic, It refers to the materials of what bearing balls are made of.
STEEL : Most of the bearings are made of steel, and the quality of the steel and the other components will determine how fast and strong they are.
CERAMIC : Ceramic Bearings, haver ceramic balls, lighter and stronger than the steel balls. Also are faster due to less friction and are self-cleaned, knocking dirt off as they rotate. Ceramic bearings are top range.
ABEC : ABEC rating measures the quality of materials and components, as the precision used in manufacturing the bearing . The rating system grades are 1,3,5,7,9+, as higher rate, the bearing will be faster and precise.
ABEC 1 : Generally the cheapest ones, the most crude, and the least accurate. The quality of the steel is not very high.
ABEC 3 : Are inexpensive and do not roll smoothly or quickly.
ABEC 5 : Standard for most types of skateboarding. Fast speed at an affordable cost.
ABEC 7 : Very fast and smooth, and cost slightly more.
ABEC 9+ : Extremely fast! For skaters that want to move insanely fast.
Resume: If you are starting, we recommend you ABEC 3 or 5, as will meet your expectations, and are very affordable, but if you are experienced and you need more speed, ABEC 7 or 9+ will be more than enough.