Subject: RE: Ceramic Bearings for added speed eitek1 - 2010-01-23 10:00 AM After poking around on the internet it seems that ceramic bearings make you 4% more efficient. See excerpt below.
What do these numbers mean for a rider? Well, FSA did some testing and found that a bike equipped with ceramic bearings was 4% more efficient than the same bike equipped with steel bearings. So for every 100km ridden on the steel bearing equipped bike, the ceramic equipped competition rode 104km, while expending the same amount of energy. If we assume the peloton averaged 40km/hr, that's a win by.....SIX MINUTES! Couple of comments: Let's not forget that FSA sells ceramic bottom bracket bearings and I am sure, make plenty of money from such sales. I believe it is pretty well documented that around 85% of the drag on a cyclist on a tri bike at 20mph is aerodynamic. That leaves us 15% of drag due to other reasons and clearly, bearing friction would be one. However, tire rolling resistance would be at least as big, probably more. But for argument's sake, let's split the remaining 15% evenly between bearing friction and rolling resistance of tires. If so, wouldn't we be talking about 4% of 7.5% reduction in drag? I get a .3% improvement in overall efficiency, not the 4% claimed. In a vacuum, there would be a greater benefit. I would like to try doing a race in a vacuum because my VO2 max pretty much sucks (OK, I didn't really intend the pun, just came out that way ), so I think this would be a great equalizer for me. I would certainly pick up a set of ceramic bearings beforehand. Greg |