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For the vast majority of applications (including bicycles), even so called "cheap" Chinese bearings are more than adequate if they are properly lubricated. For non-competitive riding, an automotive wheel bearing grease will keep your front wheel bearings happy for thousands of miles. I suggest solvent (70% isopropyl alcohol is fine) cleaning the balls, raceways, cones, etc, drying then immediately apply the grease to all the metal surfaces inside the bearing system. Use nitrile gloves - your finger oils are bad for bearings.

well on bicycles, weight but mostly marketing - I'd say 1% weight, 99% marketing. Ceramic balls are used in high speed (10,000 rpm and up) very high precision applications, with very careful match of thermal expansion coefficients (CTE). They must be properly (and usually very highly) preloaded; and must always be under compression. Impact loading which results in a loss of compression will destroy the ceramic balls almost instantly. Ceramic expands less than steel - and much much less than aluminum with increasing temperature. As alluded to above, they are not very good for low speed applications (all bicycle applications are low speed). If you are professional road racer, and your mechanic adjusts the bearing preload every day based on the expected ambient temperature - they are okay, and may be worth the weight reduction. If not, they will not last very long. The pro does not care, as they will be replaced at least every week.

Front wheel bearings should last for years and provide you with thousands of miles of travel---but they won't last forever. In some cases they even fail completely if they haven't been maintained correctly. Part of a maintenance schedule should include replacement of wheel fag bearings before they fail. The procedure isn't that difficult if you have about an hour and a few small tools. Front and back wheels are similar in procedure to change bearings and only require slightly different tooling.

Take the wheels off the bicycle beef before greasing the wheel bearings.A mixture of 50 percent white teflon bicycle grease and 50 percent green axle grease works well on front wheel bearings.Don't make the bearing cone too tight when screwing it back into place. Front wheel bearings shouldn't have any play in them and need to roll smoothly.

Wheels with quick release (QR) axles present an additional problem in that closing the QR alters koyo bearing clearance. Closing the lever requires increasing manual force with a slight over-center feel near the end of the stroke. This lever force arises from compressing the hollow axle and stretching the skewer. The ratio of elastic length change between axle and skewer is that of their cross sectional area and active lengths.

Although adjusting QR force is a safety consideration, it is also one of bearing life. It should be kept at a constant level once the desired closure force has been determined. Rear vertical dropouts require a lower and more predictable closure force than was formerly required with axles that could move forward from chain tension. Because vertical dropouts do not rely on friction to resist chain load, many hubs now [front wheel bearings] have smooth faced jam nuts that do not damage dropout faces as older knurl faced ones did.

cone 95528

cup 95925

UG215-47V22