tech info

What are ceramic bearings?
Ceramic bearings usually refer to ceramic ball bearings. Canonically, ball bearings are made from hardened chrome steel. Ceramic balls can be made of various materials such as zirconia, alumina or silicon nitride. The most common material used is silicon nitride as it is more durable and less brittle than other ceramic materials. Ceramic cartridge bearings are a bit more involved. Pure ceramic cartridge bearings use ceramic balls on ceramic bearing surface. The ceramic bearing surface is extremely difficult to manufacture and thus very expensive. Most ceramic cartridge bearings are actually hybrid bearings. A hybrid bearing is a bearing with ceramic balls on a steel bearing surface. Hybrid bearings offer incredible performance (if done correctly) over conventional steel on steel bearings.

Why are ceramic balls better than steel balls?
First, ceramic balls are almost twice as hard as bearing steel. The harder the material, the less the bearing will deform. Additionally, the harder bearing material will be more durable which is why ceramic bearings are known for their durability. Ceramic bearings are also less dense and in theory will accelerate more quickly and dissipate heat more readily. These last two properties are not as important to cycling applications as ceramic bearings are often rated to over 10,000 rpm. Last but not least, ceramic bearings can generally be made more round than steel ones. The ceramic balls we use are Class 5 or better. The Class of a ball bearing refers to its sphericity in millionths of an inch. Thus, our bearings are round to 5 millionths of an inch and better in many cases. In comparison, the best bearings that come stock in Campagnolo Record or Shimano Dura-Ace is Class 25. That means our ceramic bearings are at least 5 times more round which results in less rolling resistance.

So what makes Superfly ceramic bearings so good?
The ceramic bearings we exclusively use are Enduro ceramic bearings from ABI Industries. After thoroughly scouring the world (literally) for the best ceramic bearings, we chose ABI due to their high level of quality and commitment to the manufacturing of ceramic bearings. Unlike less expensive ceramic bearings that are sold on various internet sites, the bearings we use are designed from the ground up to be the best performing and most durable. All of the parts used for our ceramic bearings (including the ceramic balls) are manufactured in Japan at a facility that also produces ceramic bearings for some of the most prestigious (and most expensive) bearing manufacturers in the world.

The steel bearing surface is a special type of chrome steel which is much harder than stainless steel. Stainless steel is actually a poor choice for ceramic balls to roll over as the stainless can wear and pit quickly. The steel bearing surfaces are then cryogenically treated to just above absolute zero (0 degrees Kelvin) to align the molecular structure of the bearing surface. This treatment makes the bearing surface more durable and less resistant to pitting.

Next, the ceramic balls are positioned using a special polyamide retainer for low friction rolling and also to evenly spread the grease as it rolls. Why even use a retainer? If a retainer is not used, the balls can make contact with each other. Furthermore, the balls will be spinning in opposite directions when they touch thereby increasing resistance. Think of when you are riding behind someone on your bike and the wheels touch. Since the front side of your front wheel is touching the rear side of the rear wheel in front of you, the two wheels touch with each wheel spinning opposite to each other. Retainers prevent this from happening.

Even the grease used in the bearing has been specifically chosen. The grease used in our bearings is specially formulated Kyodo Yushi grease for hybrid bearing applications. Furthermore, our bearings have 30-35% fill rate on each side guaranteeing at least a 60% total fill rate with even distribution of the grease.

Lastly, the seals have even been thought out. The seals precisely fit the cartridge for low seal drag and for prevent contamination. Oftentimes, seal drag contributes more to bearing friction than the balls themselves. The seals in our bearings start off smooth from the beginning.

Do ceramic bearings make a difference?
In a word, yes. There have been many claims about how much energy ceramic bearings save over conventional bearings but the easiest way to convince yourself is to ride a set of wheels with ceramic bearings. Many customers who have tried a set of wheels with ceramic bearings immediately notice the difference. Ceramic bearings are also great for extreme applications such as riding in bad weather, mountain biking and cyclocross where bearings wear out quickly. Ceramic bearings will still smooth longer and last much longer than conventional bearings which easily justify their price.

How are ceramic bearings installed in Superfly’s wheels/bottom brackets?
When we install bearings in our wheels and bottom brackets, we use high end bearing pullers and presses that correctly align the bearings. This will guarantee that bearings will spin as smooth as possible. We check all of wheels and bottom brackets after installing ceramic bearing installation for correct alignment.