Robert Stout's Website..... rlstout.com |
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There are many kinds of bearings.... This discussion has to do with ball bearings similar to the ones used in the wheel hubs of motorcycles. Ball bearings are made in three basic styles... "Open", "Shielded" and "Sealed". An "Open" bearing has nothing on either side to seal any lubricant into the bearing, a "Shielded" bearing has a metal shield on either side of the bearing and a "Sealed" bearing has a rubber oil seal that seals lubricant in the bearing... If you are going to use a bearing in something such as a motorcycle transmission where it would be constantly bathed in transmission lube and there is no way for dirt to get in than an "open" bearing would be used...If the bearing is used someplace where it would be exposed to dirt a "sealed" bearing would be used... Bearing manufactures also make standardized sizes... Numbers are assigned to these standardized sizes. They call this the "bearing trade number" You will find that most ball bearings are made to these standard sizes and in many cases you can get a bearing that will work at a local bearing shop for much less than the buying the same bearing at the local motorcycle dealership.... The big difference is that different manufactures use different prefixes and suffixes to designate manufacturing tolerances, speed ratings or weather the bearing is shielded or open... For example....One of the bearings in a Kawasaki H2 front wheel has a part number of 601B6203 ... Kawasaki's standard part number for bearings is 601B plus the "bearing trade number" (601BXXXX where XXXX is the "bearing trade number") Kawasaki uses "open" bearings in their front wheel so In other words a Kawasaki Part number 601B6203 would be a number "bearing trade number" 6203 bearing that is open (no seals or shields).... A wheel bearing doesn't need to be a high speed bearing so you can get a suitable 6203 bearing for $10 or less ... Kawasaki charges a bit more for the same bearing.... Some Yamaha part numbers can be deciphered as well.... for example a Yamaha part number 933306-30309-00 is a 6303 bearing... While this isn't a complete list of the trade numbers, here are many of the metric bearing trade number's and the their sizes:
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