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Ever since the ancient Egyptians used the trunk platform to move the huge stones into place when they were building the pyramids, bearings have helped mankind continue to move forward. 

Interestingly, the first official patent for ball bearings was for bicycles. In November 1869, French mechanic Jules Suriray installed them on a bicycle that later won the world's first city-to-city bicycle road race, Paris-Rouen. Nowadays, all cyclists are more familiar with the bearing, because it is something that will fall apart. During the disassembly process, it requires hands and knees to search under the workbench or refrigerator for hours to retrieve it.

Leaving aside history lessons, bearings play an important role in how the bicycle moves freely. Pedals, cranks, wheels, earphones, guide wheels... If it rotates, the bearing is in its center. Without them, it would be difficult for us to ride quickly anywhere. There are many different types of bearings, so it is necessary to clarify some definitions at this stage to eliminate confusion. 

When we refer to "bearings", we are referring to components composed of five basic parts: balls, seals, ball cages, raceways, and grease. The concept is simple-several balls are sandwiched between two concave surfaces (races), allowing them to rotate with each other with minimal friction (one is usually fixed). Cages and seals hold everything in place and prevent dust from entering, while grease lubricates and protects the mobile system.

Most modern bicycle applications now prefer "cassette bearings". Compared with the old "loose bearing" system, these sealed units have several advantages. The old "loose bearing" system is mainly limited to low-end and cheaper components (although a few top-level components still choose to stick to loose balls and cups). And cone system, the reason is to its finer adjustability). Cartridge bearings generally require much less maintenance, and when they eventually wear out, they usually do not cause terminal damage to the surrounding parts. In addition, they can be easily replaced.

"Ball bearing" refers to the ball itself. Ball bearings can be made of different materials, including chrome steel, stainless steel, and ceramics that have recently entered the bicycle world (and more of them), usually silicon nitride (Si3N4). A "hybrid" bearing is a bearing with ceramic balls and metal races. 

Not all bearings are created equal, no matter what they are made of. I once saw a top bicycle repairman take out a jeweler's magnifying glass, cut a visibly clean and shiny ball bearing, and said,'I won't put them in my wheels. They are like cake decorations. As with most things, there is a hierarchy of bearings, where you get what you pay for. 

The cheapest ball bearings may not even be perfectly round. Bearings are usually graded according to roundness grades, in units of one millionth of an inch. A 200-grade steel ball means that it is round with a tolerance of 200 millionths of an inch. Therefore, a lower number—for example, level 25—is a more accurate ball. For bicycle sizes, the grade ranges from 2,000 to 3, and anything below 100 is generally considered a "precision ball." This grading system is used for further grading of steel balls and ceramic balls, as well as surface roughness. Ceramics usually get smoother results-this is just one of its inherent advantages.

Do these small differences in roundness and surface have any real impact on the average cyclist? Alan Weatherill of Hope Technology, a British component manufacturer, said: “Ultimately, if the balls are of poor quality and are not perfectly round or smooth, they will cause increased friction and premature wear on all parts of the bearing. It will inevitably fail. Quality, no matter what material it is, is the most important factor. 

The importance of ball bearings is far greater than their size implies, which is why the bicycle industry is so fussed about ceramic balls. The trade goes like this: Ceramic balls are generally rounder, smoother, harder, and lighter than steel balls, so theoretically they should provide less friction and longer life. They are also much more expensive, so before spending money, it is worth taking a closer look at the potential benefits of ceramic balls...

Jacob Csizmadia, the founder of CeramicSpeed, was the first person to introduce ceramic hybrid bearings into professional cycling in 2000. CeramicSpeed's test data claims to be 6 to 9 watts more energy efficient than steel bearings. If it is true, then a lot of energy and potential time can be saved by simply replacing the bearing, but not everyone thinks that ceramic bearings are some miracles that we believe.

Weatherill explained why Hope felt it was necessary to provide ceramic bearing options for its wheels and bottom brackets: "We did this because [the market] asked us to do this. We did not do it from an engineering perspective. A lot of it was hype. Ceramic bearings Used in industrial machines because they rotate at 25,000 rpm and have significant advantages, but bicycle wheels only rotate at 300 rpm, so compared with the very high-quality steel balls we have used, the difference very small.' 

CeramicSpeed ​​Director Martin Banke is keen to refute Weatherill’s views and defended his test data by saying: “Ceramic bearings are not marketing hype. Ceramic balls are better than steel balls under any load on the bicycle—assuming proper high-end ceramics. quality. 

Bank believes that it is this quality problem, which may be why some people still do not believe in ceramic bearings:'[Other manufacturers'] The quality of ceramic bearings varies. This means that there are some very poor, usually cheap bearings on the market that have higher friction, higher brittleness and shorter service life, which is why some people still have good reasons to question ceramic bearings. 

When asked about Weatherill’s statement about the necessity of ceramic balls at lower speeds on bicycles, Bank said, “If you look at the first page of a big book about hybrid bearings, you’ll say that the answer is no. They ride bicycles]. In fact, this is far from the case. Ceramic bearings were originally invented for high-speed applications, which is correct. In this application, the ball’s light weight, high stiffness and low bearing friction make the machine Can rotate faster without damaging the bearing. However, like many other technologies, ceramic bearings have also been proven to have excellent characteristics for bicycles. Materials such as carbon fiber were not originally invented for bicycles, but now Everyone is using it.

As if supporting Bank’s point of view, after the initial period of uncertainty, Chris King recently entered the ceramics market. This American brand may be the most prestigious brand in the field of bicycle bearings. In the early days of the ceramic "craze", Chris King was not keen on leap forward, and continued to struggle in the corner of steel for a period of time. However, it now also offers ceramic upgrades for all its components, excluding headphones.

'Since the advent of ceramics, there has been a lot of hype around ceramics, and many products on the market do not have the overall design of this material to achieve the best performance, so in some cases it has given it a bad reputation,' Said Kim, the owner of the company of the same name. "The decision to provide ceramic options is a conscious choice, not a market-driven choice," he emphasized, and by saying, "The performance of high-quality steel balls and lubricants is very good. We have years of experience to prove this. In order to understand the properties of ceramic balls, we conducted extensive tests on them. The decision to provide ceramic options was made after we proved to ourselves that there are real benefits. 

King claims that one of these benefits is that "ceramic balls have the extraordinary ability to maintain their "real" spherical shape under load. This creates conditions for our ceramic-equipped parts to have a very long and smooth operating life. 

However, King admits that the performance advantage is not great: "Our research shows that our hybrid ceramic bearings provide subtle benefits for discerning consumers." The main benefit lies in the ability to use lighter lubricants. King said: "In King hybrid ceramic bearings, the use of ceramic balls reduces the lubrication requirements, so compared to similar steel bearings, lighter grease and less grease can be used. Less lubricant means Less bearing resistance. 

This feels like a "marginal revenue" field. If all parts are ceramic and not just balls, maybe more performance can be extracted from the bearing? Chris King, Hope and CeramicSpeed ​​all offer "hybrid" ceramic bearings (ceramic balls in the steel ring), so would the ceramic on the ceramic be better? 

King stated that he "has not been able to prove the need for full ceramic bearings," and pointed out that cost is the biggest reason not to use full ceramic bearings. Bank suggested that the ceramic race may be more brittle and more likely to fail, so he also insisted on using hybrid power.

When asked about their views on the future, both Bank and Kim agreed that ceramic bearings will continue to exist. Bank even predicted that "the number of aftermarket upgrades will increase substantially-many people may buy bearing upgrade kits in the next year after buying expensive wheels in one year."

If you have already done this, please raise your hand... put the bike on the workbench or upside down, let the wheels or bottom bracket spin quickly, and see how long they spin. The longer they spin, the better the bearing, right?

This is a technique used by manufacturers in bicycle shops and trade shows to invite punters to spin the wheel or BB and marvel that it has turned an era effortlessly. An easy way to achieve this is to remove grease from the bearing and use light oil to reduce friction and make it easier to spin. This is something that road racers, especially time trial players, used to try to gain an advantage.

Of course, this does not take into account that the pedaling action and the weight of the rider will generate considerable force on the bearing. Once you sit on the bike, let alone sprint on the road, the ball will be forced into the game. Unless the lubricant can withstand this force, it will only be squeezed out of the contact surface, causing the ball to be unlubricated. It runs directly against the surface of the raceway. 

Bank explained, “A steel bearing without seals is completely clean and dry and can rotate well on the bracket. But once you increase the weight, the steel ball will contact the steel raceway, and the friction will increase sharply. The same effect can also be achieved by adding too much clearance in the bearing. On the road, you will experience increased clearance and wear rates, and the bearing may quickly fail. 

The moral is: don't believe in rotation-literally. The only way to ensure longevity and real performance gain (if insignificant) is to determine the quality of your ball. 

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