Bearing from the beginning of the use of guide the first material fatigue phenomenon of this period of time is related to the bearing speed, load size, lubrication cleanliness. 

Fatigue is formed by the shear stress of periodic appear below the surface of the load as a result, after a period of time, the shear stress is causing tiny crack skull, then gradually extends to the surface, when the rolling piece after the split cranium, then some crack block off, form the so-called "peeling phenomenon", and then continue to expand as peeling, bearing damage in use. 

Above is the description of the bearing fatigue, it was originally occurred under the surface, while the original skin conditions are usually very mild, but increased with the increase of stress and crack block, lead to the spread of the peeling area, the damage situation usually lasts a long time, its visible stage is when noise and vibration increase. 

Bicycle bearing damaged in the primary stage, is likely to be just turns hard to feel, and later found that the rotation are pitting, and once appeared pitting feeling, bearing is not can't use, just proceed in each beads and shaft gear and shaft bowl occurs more wear and more serious damage, because the bike is a way of low speed high extreme pressure type bearing, so even if the surface peeling phenomenon is serious, is not so used, but intangible silent your motivation of energy consumption, and the feeling of you is likely to be just think don't know why not ride a bad car. 

Therefore, it provides enough discovery time for the user before the bearing is completely damaged. Don't ignore the existence of this friction, which will slow down the cycling speed and make the long-distance energy consumption greater and the speed slower. 

If subtle for surface roughness, if there is proper thickness of lube film, the surface stress generated by the probability is quite low, which is why the choice of appropriate for the reason of engine oil for lubrication, however, if the load exceeds the oil film pressure value of pu (the fatigue load limit, such as high speed, high pressure shock), material fatigue will come sooner or later. 

Cause of premature bearing damage - (improper lubrication)

Although "maintenance-free" rubber sealed bearings can be installed, 36 per cent of bearings that fail early are still due to improper application of grease technology. 

Any improper lubrication bearing, inevitable failure ahead of schedule, because of the bearing is glue is not allow to drag down, part of flower drum, and congenital use the incorrect grease, and late will not be changed when using grease, or after carbonization metamorphic pollution in grease without a change in time, that you of flower drum is hard to have enough long life and good lubrication degree. 

We now encounter most of the small specifications of deep groove ball bearings, such as 609,6,000,6001,6200, which in industry are used for small motor stator and rotor use of the perlin, and such small perlin is usually pre-loaded at the time of purchase is low viscosity, high lubrication of the broad spectrum grease. 

And we had a lot of mistakes in the past the purchase and use of this kind of price is quite expensive grease, such as we used to purchase the SKF LGMT - 2 synthesis of lithium base grease, this is a low torque, low friction small motor lubricating oil, it is also the most small SKF cultivates the use of the forest, the price is very expensive, 200 grams of packing prices as high as 60 yuan, but that the oil viscosity is only 110, for high load, extreme pressure, reciprocating motion ability is bad, and according to the usage of axle by oneself, this should be a low speed.High extreme pressure (because a lot of pressure only focus on a few tiny palin, impact and jumping will produce greater pressure), so we chose the later SKF LGEP - 2 synthesis of lithium base grease, and that although the price is expensive ($155), but its viscosity 200, high load, high water-proof, high anticorrosion, high seismic, on low torque friction index, though less LGMT - 2, but it is completely suitable for axial and car before and after the first bowl of bicycle group (today we have some old flower drum, such as is used in rm40 repair lubrication LGEP - 2).