Ceramic Bearings for added speed

eitek1 - 2010-01-23 9:38 AM That I don't really know. If I had enough time I could probably caculate the gain somehow. 

I imagine that the gain you would get would be at least 50% or more as significant as the gain you would get from Aero wheelsets at a fraction of the price.

That is just my opinion. A efficiency gain from frictional losses is still a gain in efficiency.

How much gain do you get from Aero wheelsets?

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!

eitek1 - 2010-01-23 11:00 AM

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!

gsmacleod - 2010-01-23 8:41 AM

Pure marketing BS.

Shane

Gaarryy - 2010-01-23 3:02 PM what about ceramic bearing with dimples??

eitek1 - 2010-01-23 8:21 PM I agree that ceramic bearings excel in high speed/ High temp applications and a bike isn't one of them. That doesn't mean that the other benefits that come along with ceramic bearings won't be realized.

Think of it like this. Ceramic bearings are "rounder" than conventional steel bearings and have a harder more uniform surface area. Due to this they have a tendancy to deform less under load. I agree that the deformation will be absolutely minimal but it will be there.

For hypothetical reasons lets say you are riding in a vacuum. You suddenly stop pedaling and start coasting. Will you go farther on a bike that has steel wheel bearings or one that has ceramic wheel bearings? My guess is that you will go farther on the one that has ceramic wheel bearings. I would guess you would actually go a lot farther. If that is the case and I am right then there is some gain to be had with ceramic bearings. Is it in line with how much they cost, I dont' really know.

Here is a link from a website where they tested various bearings to measure losses. They brought the flywheels up to speed using a motor. On the ceramic bearings at speed the motor used 10% less energy to keep it moving. That is huge.
http://machinedesign.com/article/ceramic-bearings-save-energy-extend-life-1005

"At 3,000 rpm on the bench-top flywheel setup, the all-ceramic bearing used 1.25 W less power than the all-metal and metal-ceramic hybrid bearings. The flywheel drive motor drew 10 to 12% less current when running ceramic bearings than when metal-containing bearings were used."

I found where they actually did the test in a vacuum on a rotating disc to see how much drag a bearing seal made. What they found was the one with the best seal rolled 400+ feet farther than the "standard". Keep in mind this is just the difference in seal types.

I found a great write up on the actual reasons for drag on a bicycle. It's a great article. http://www.slowtwitch.com/Tech/The_Physics_of_Moving_a_Bike_163.html

I don't really actually care either way.  I am not fast enough or do I have enough money to justify Aero Wheels or Ceramic bearings. I just thought this would be an interesting discussion which it is. Heck, I just got clipless pedals and was kind of proud of that

brown_dog_us - 2010-01-24 9:42 AM

Ceramic bearings would be one of the last upgrades I would make. The science behind the claims is shaky and the gains are most likely very small.

Experior - 2010-01-23 9:46 AM I think (emphasize think -- I'm not an expert) it is widely accepted that they are more durable, and that high quality ones are rounder and more consistent in size than steel.  I've seen claims of 10W gained, but I have no idea whether it's true.

A few places that cater to cyclists (some already mentioned):

http://www.fullspeedahead.com/

http://www.bocabearings.com/

http://www.ceramicspeed.com/

http://www.endurobearings.com/

kdlsch111 - 2010-01-23 1:50 PM I will be blunt. It aint happenning. We have more BS in our sport than any other by far.

pga_mike - 2010-01-24 5:34 PM
10 Watts??? I'd give you the tip of my right pinky for 10 watts!