Worldwide Bearings : Ceramic Bearings, are they worth it?

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Article courtesy of ‘The Horse’ Back Street Choppers

 

Getting into Ceramics and Talking About Hybrids!

Over the 40+ years of owning a shop and building race bikes, there has been many claims of products that give you more power, longer lasting and cooler running temperatures. AND, over the years almost all of them do not live up to their claims. Some will give you some more power, but the downside is usually a shorter duration of service.

Over the years, I know of some who are using ceramic bearings. In truth, they are using ceramic hybrid ball bearings. What that means is the inner and outer race are still made of steel and the balls are made from ceramic. I contacted Dave, the owner of Worldwide Bearings, and ordered a set for the RD350 race bike.

The reason I contacted Worldwide Bearings is that they were one of the first, if not the first, to bring hybrid ceramic bearings to the market. Hybrid bearings were being used in machine tools. In 1997 Dave read about ceramic bearings and started his research on why at the higher running speeds, those hybrid ceramic bearings were being used.

The ceramic balls are 60% lighter and offer 40% less friction over the steel balls. The lighter ball weight lets the ball roll at fast acceleration and high speed vs the steel ball which can scuff during these conditions.

He did testing with many NHRA Drag racers and all that tried the hybrid bearings went faster the first time out.

BUT, is this another claim for more power, longer lasting and cooler running temps again?

So, I decided to do some testing in my shop with my bike. I went into this thinking they may be a little better in one area, but would probably not do as well in another.

1. Weighing the hybrid ceramic bearings total weight

I weighed both the hybrid ceramic and steel ball bearings. The weight difference was 18%. Remember, this is total weight – so all the weight savings was in the ceramic balls. So the claim of 60% less ball weight for the ceramic balls seems correct.

2. Spinning the wheel with a drill

The first rolling resistance test was to spin the wheel with a small electric drill (pic. 2), and after it levels off at its full speed, it is timed to see how long the wheel still spins. I did this 3 times and the average time was 1 minute and 14 seconds (pic. 3). The wheel spun very easy and I thought that there was no way just a bearing change would make much of any difference.

3. Rolling time for steel bearings average.

4. The steel balling bearing had an amperage of 1.52

The next test was to see how much power the drill needed at full speed. The drill and grinding wheel alone had a power use of 1.38amps on my digital amp probe. The amperage the drill used while turning the rear wheel with the steel ball bearings was 1.52 amps (pic. 4). I then removed the steel ball bearings and replaced with the ceramic hybrid ball bearings. Be sure while installing the new bearings that you do not forget the hub ball bearing spacer (pic.5)! I will have a detailed tech article on how to do this in an upcoming issue.

5. Be sure to install the hub bearing spacer.

I re-installed the rear wheel and torqued the rear axle to the correct torque and started to run the same tests. The steel ball bearings were new ones and only had about 100 miles on them. This was not quite fair for the hybrid ceramic bearings since all bearings have a break-in period which breaks in the seals and channels the grease. But, I did the test anyway without any break-in time for the hybrid ceramic bearings. I spun the wheel up with the drill and the free spin time averaged a time of 3:14!! (pic.6) I couldn’t believe it! That is 2.75 times longer than the steel ball bearings.

6. The hybrid ceramic bearings had a LONG free spin time.

Next was the amperage that the drill needed to spin the wheel. Remember, the drill alone without spinning the tire took 1.38 amps. The drill only needed 1.42 amps to spin the hybrid ceramic bearing wheel. (pic. 7).

7. Much lower amps needed to spin the hybrid bearing wheel.

As you can plainly see in my testing, the ceramic bearings clearly have less rolling resistance. But there were several other questions I still had, so I asked Dave.

Why do the ceramic balls have less resistance?

The balls are rounder, harder and lighter than the steel balls. They have less centrifugal drag because they are lighter which also makes them have less ball skidding; the heavier weight of steel balls in high speed applications causes them to skid and not spin.

How does heat affect ceramic balls, and as they get hotter, do they have more resistance than steel ball bearings?

Ceramic balls are good to 2000 degrees F where a steel ball will start to deform above 300F. Steel bearings as they get hot, heat expansion and clearances get tighter as the bearing gets hotter. This expansion causes more resistance and more heat buildup. The ceramic balls run that much cooler with a lot less heat expansion.

What about dynamic loads?

Will a ceramic ball have the same load as a steel ball? Our ceramic balls are ALL USA made from Cerbec, Hoover and SKF/MRC. They have a dynamic load that is actually 30% higher than the steel balls.

I heard that ceramic balls can fracture easily. Is this true?

When we have visitors at Worldwide Bearings, we get asked this question. So, we have a few 1/8” ceramic balls in a Ziploc bag. With a hammer and a piece of cast iron they can hammer on the ceramic balls, and they really beat down on them with the hammer! So much, so that the ceramic balls get embedded in the cast iron. We had an AMA Super Bike team put them in a press to test and they actually pushed the ceramic balls into the steel race with no ceramic balls breaking.

Will a hybrid ceramic bearing have the same life expectancy?

Ceramic bearings will last 3 to 5 times longer on average, and I have seen up to 8 times longer.

What special care is needed when they are installed?

They are installed the exact same way as a steel bearing.

Where are your bearings made?

Every bearing is hand assembled with an exact fit to where it is being used. As an example, we do some high speed crank bearings that have a much looser fit than a wheel bearing would. After determining the fit, we hand assemble each one and they are lubed with Mobil Polyrex EM grease that is also USA made.

What else do you think everyone should be aware of about hybrid ceramic bearings?

Don’t be fooled that a much cheaper bearing found on eBay is the same. I have had a few customers try to get by with the cheap Chinese version and after one hour he did over $2000 in damage to his engine. There is a big difference in quality!

The average cost per bearing is about $50 more than a quality steel ball bearing. For the additional amount that you spent, you will get more power to the ground, a much longer lasting bearing, better fuel economy, less heat build-up, more load bearing, stronger bearing and it is also made in the USA!

– Article by Steve ‘BrewDude’ Garn

 

 

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