And if abec 5 is better. Should I put them in my penny board?
5 is always better than 3 unless you are trying to restrict your speed. Yeah, put them in.
ABEC is basically meaningless for skates or boards. It is a vibration (higher numbers may roll slower) for high speed machines that are running at speeds that would be around 200 mph on a board. The quality of the maker is more important and some abec 3 bearings may run faster than other abec 5 bearings. The durability of the bearings is also more up to the maker and is not covered by anything in the ABEC standards. Bones is known for making very fast running bearings (they, along with Twin Cam and Zero Drag, make bearings that violate the ABEC standards so they can roll better) but have a reputation that sneezing near them will cause them to rust.
