Quick and Dirty
While riding a bicycle, there are a bunch of things that affect overall speed and effort. Some of these are: tire flex and pressure, frame flexing, chain friction, road bumps, road material, wind, rain, and the list goes on and on.
Microns of tolerance in a bearing will have a smaller effect on the speed and rolling resistance unless your bike is set up with components (bearings included) that are in reasonable condition. If you want to know the engineering behind your bike components, keep on reading. If you want to skip ahead and purchase your bearings then go right ahead.
Difference Between ABEC Bearings
A bearing is defined as a machine part which allows another part to turn or slide. In order for a bicycle to function correctly, a bearing is needed in these key spots:
- Bottom bracket
- Front & rear wheel hubs
In order to ensure bearing quality, the American Bearing Manufacturers Association (AFBMA) created precision class standards. Bearings are manufactured according to the set standards given by Annular Bearing Engineering Committee (ABEC) of the AFBMA. The ABEC rating system includes ABEC grades of 1,3,5,7, and 9.
The higher the ABEC rating, the smaller the tolerance and precision. Small tolerance and high precision bearings are needed for industrial machines, not for skateboards or bikes. In fact, if you were to buy an ABEC 7 or 9 it may not last as long as an ABEC 1, ABEC 3 or ABEC 5, which are best for skateboard or bike use.
Technical & Engineering Information
The difference from an ABEC 1 to an ABEC 7 bearing for radial runout is 7.5 microns for a 6000 (10mm ID) bearing.
This means that if a skilled person with a dial gauge and a professional set up checks the bearing for roundness on the raceway itself, as they are spinning the bearing, the deviation of the radius from nominal for an ABEC 7 is 2.5 microns and an ABEC 1 is 10 microns.
This is not measuring with a tape measure or even a micrometer. This is measuring with dial gauges that are frequently calibrated, a correct set up of most likely custom tools and a temperature-controlled room. This takes training, practice, and time.
Microns and Ball Bearings
Let’s take a look at what 7.5 microns actually is:
A human hair is 17-181 microns, a sheet of paper is about 100 microns thick, and an average red blood cell is 8 microns.
Proper bearing grease, proper bearing grease fill, contact vs. non-contact seals, will all make a difference to the rolling effect of a bearing. The difference could be like riding against a 20 mph vs 0 mph gust of wind. This isn’t the same as feeling the precision of the bearing.
Feeling the precision of a bearing is like riding on a gravel road vs. a newly paved road (i.e. roughness vs. smoothness). This means that a proper set up ABEC 1 bearing could easily feel much better than a poorly setup ABEC 7 bearing on your bike.
This article was meant to shed some light on ABEC bearings and what bearing types bicycles and skateboards require. Ready to shop our store and get your new bearings?