Now do you see what I mean by these tolerances being mangled by the first few minutes of riding down the sidewalk? The pressure of you riding, along with the shocks of bumps and the cracks in the sidewalk will quickly add a lot more eccentricity to this groove, but nothing that you can truly notice at all.
These tolerances only mean something if the bearings are used in the capacity they were intended, which is high speed and precision industrial machinery. So for all that cash you threw down on some ultra machined, cryogenically treated ABEC 9 bearings, you might as well have just bought ABEC 1 bearings, because after about 5 minutes of riding, you won’t be able to tell the ABEC 9 from the ABEC 1. As far as speed goes, the only way those ultra fancy ABEC 9 bearings would begin to show you any benefit is if you were able to reach a speed of about 240MPH on a perfectly smooth surface, with 65mm wheels and grease as a lubricant.
If you want to know what things make a greater difference in regards to speed and bearing longevity, look at things like the type of seal used, as well as the materials used to make the ball bearings themselves, not to mention the precision at which the ball bearings were made. Harder bearings will last longer, and rounder bearings will roll truer, longer, and probably faster. Most ball bearings are made of either stainless steel, or chrome steel. However, as previously mentioned, you can get bearings that use ceramic for the balls from companies like Bones with their Swiss and Redz lines, and Quadline.
While there is no evidence these bearings are inherently any faster, one could come to the conclusion that they are superior due to greater hardness, and the fact they will not corrode like stainless and chrome steel balls will. They also will be lighter (though with being so small the weight savings is negligible), as well as having superior heat dissipation, for what that might be worth. They also require less lubrication that standard steel skate bearings.
Speaking of lubrication, this is one of the other methods by which you can actually make a difference in your skate speed and overall rolling distance, as well as significantly increase the life of your bearings. Teflon based oil lubricants work quite well (one article I read said Slick 50 One Lube was the trick). WD 40 can also be used, but being mostly liquid, they will offer no protection once the lubricant has been expelled. Personally, I only used WD 40 to de grease dirty bearings for re-packing. One could also use lithium based grease for longevity of the grease, while maintaining a lighter weight like oil for speed.
So there you have it, the real scoop on ABEC ratings. Feel free to educate your buddies on this stuff, or further look things up yourself for further learning.