Ceramic Wheel Bearings
Ceramic Bearings: What are they?
It is important to remember that the ceramic bearings used in racing are constructed using conventional hardened steel races, but with ceramic balls replacing the common steel type. Without question, ceramic bearings raise the performance bar a significant amount.
The two most significant reasons for this is they are almost 60% lighter in weight than steel balls and due to the way they are made, they are “rounder” than steel types. Rounder you ask, how much “rounder”? Modern steel bearings typically will have tolerance variations between 50 and 60 millionths of an inch, whereas a grade 5 ball will only have 10 millionths variation, a considerable difference. Again, due to the way they are manufactured, ceramic balls have an improved surface finish compared to steel balls. Smoother, Rounder, what more could you want?
Why are ceramic bearings better?
There are other advantages that should be taken into account. The ceramic balls in ceramic bearings have a considerably lower amount of thermal expansion compared to steel types. In other words, high heat doesn’t make them swell in size. This allows tighter tolerances, if needed. They also run cooler in operation. This reduces ball expansion and improves lubricant life.
The balls in ceramic bearings are much harder than steel balls (over 100% harder). This, combined with their excellent surface finish is the reason they dramatically out-wear steel types. In identical running conditions, the balls in ceramic bearings exhibit less than 10% of the wear of steel balls. They last longerrrrrrrrrr, helloooooooo, that’s a no brainer in itself.
Are they worth it?
There is no question that ceramic bearings are "freer rolling" than steel types, but their higher cost, understandably, gives pause to many. The primary reason is the cost of the ceramic balls. The other is that they are hand-built and custom "clearanced", not mass produced. There are those of us who insist on "the very best" of everything, while others do not. If you really, really, really want to go faster or quicker, then ceramic bearings is a hands down winner.
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!
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