Ivanb Posted July 16, 2007 Share The friction in bearings depends on; seals, shields, cage, lubrication, clearance and type of balls (steel vs. ceramic). <?:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />To demonstrate this I upgraded a Shimano Dura Ace hub so standard ball bearings could be fitted into the hub. A 12g steel ball was attached to the carbon rim and the wheel placed in a front fork. By releasing the wheel from the same point each time and by counting the motions until it stops, difference in bearing friction could be detected RS1 Means Rubber Seal (contact)Z Means Shield (non contact)RZ Means Rubberised Shield (light contact) 6000 2RS1 steel bearing, grease 36000 RS1 steel bearings, grease 66000 RS1 steel bearings, oil 9 6000 Z steel bearings, grease 216000 Z steel bearings, oil 52 6000 RZ hybrid bearings, oil 118 Used in 2001 Tour de France 3-4000 km without lubrication. 6000 RZ hybrid bearings, oil 325 Number of motions until the wheel stops.(The higher the number, the lower the friction) This is the number of revolutions so yesthey do make diffrence Link to comment Share on other sites More sharing options...
Ivanb Posted July 16, 2007 Share Let me throw a spanner in the works. Our new SABB Self aligning Bottom bracket does fantastic things. It allows the bearing to stay paralell to the axle. mmm think about it each time you put pressure on one crank the axle bends and the top and bottom of the bearings on each side stay in contact. With the SABB it stays aligned http://www.rotorbike.com/2006/sabb.htm Link to comment Share on other sites More sharing options...
Gumpole Posted July 16, 2007 Share I had a look at the website, very interesting that Rasmussen endorses there product. Rasmussen is a brilliant cyclist (in the yellow jersey too)... but apparently weights his cycling jerseys! I think that this attitude sums up the whole ceramic bearing debate! Link to comment Share on other sites More sharing options...
AttieSlabbert Posted July 20, 2007 Share Ivan,Only give the following info on your ceramic bearings please!density, Vickers hardness, compressive strength and composition.Thanks a lot! Link to comment Share on other sites More sharing options...
SwissVan Posted July 20, 2007 Share Dear Attie Ceramic bearings aren't all they're cut out to be. Yes they're harder' date=' but now they're destroying their softer (steel) races very quickly. Hubs are more expensive to replace than bearing balls. Yes they're lighter than steel but the saving on 38 balls is less than the weight of a strand of spaghetti. Let's get realistic. Bicycle wheels spin relatively slowly compared to hard disks and turbo chargers, where ceramic works nicely. There is no heat build-up in bicycle wheels. Ridgidity - just hardness in this case, see point one. Anti-magnetic? Who cares. Good mechanics keep their balls togher with a magnet and retrieve stray bearings with magnets. Imagine loosing a R20 bearing ball and a magnet can't find it! Everything is prone to contamination. Dirt doesn't care what the ball is made of. Galvanic current. C'mon... lets get real. The rest of the "benefits" is just hardness and polish repackaged. 50% reduction in rolling resistance? Not so, most of a wheel's rolling resistance comes from the tyre. The bearing's rolling resistance is so small, that a 50% reduction is meaningless and cannot be measured over any reasonanble race. I don't for a minute believe these benefits cited here. A bike is not a turbocharger. Steel is just fine. JB [/quote'] JB - Pretty well summed up You kind of left out 2 points - Sales marketing and turnover Link to comment Share on other sites More sharing options...
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