Over the last few years we have been frequently asked our opinion on using ceramic bearings. Is it worth the extra cost for the possible gain in performance.
To be honest, I have always been a bit sceptical, seeing the marketing hype. There seems to be an almost mystical quality applied to the performance of ceramic bearings. This results in anecdotal reports suggesting that just telling an athlete that they have ceramic bearings fitted can give considerable benefits alone.
The market is now flooded with cheap industrial ceramic bearings which generally seem to be fragile and unreliable, but can often survive in bicycle use. However, the pounding given to a hub bearing by a racing wheelchair athlete is entirely different to the smoother and more predictable loading from a cyclist or within a machine. Add to this the twisting forces caused by the wheel camber and side loads during cornering, and the result is often poor performance and short bearing life. We have seen balls and races cracked or crushed. Racing wheelchairs and handcycles need something better…
Like all bearings, there are many grades, qualities and manufacturers. Finding the right balance between cost and performance can be a lottery. We have spent 6 months researching different bearings and have settled on CeramicSpeed, a small specialist Danish manufacturing company who hand build high quality ceramic bearings at a reasonable cost, around £50 per bearing + VAT.
If we stocked and sold the cheaper bearings (available on eBay if you want them) in the sizes which CeramicSpeed make we would actually make more profit. However, that would just be letting our customers down with sub-standard products which they don’t deserve.
- Save energy due to extremely low friction
- Designed for low rotation speed, high load application
- Last 3-5 times longer than other bearings on the market
- The 6% lower rolling resistance increases your power transfer when pushing/cranking.
- Increased top speed with improved power transfer
- High performance bearings made with special quality CeramicSpeed balls
- CeramicSpeed balls are 100% smoother and 15% harder than other ceramic balls in the market
CeramicSpeed bearings are handmade in Denmark:
All CeramicSpeed bearings are assembled by hand in Denmark, under dust free and clean room conditions. All the parts they use in our bearings are carefully selected for their quality, and are individually checked prior to assembly. Built to a quality not a price point. Assembling CeramicSpeed bearings by hand means that they can continually monitor quality throughout the assembly process, ensuring that all parts are perfectly matched, and that every single bearing meets our exacting standards.
CeramicSpeed bearings help you roll faster using less energy. This can be the difference between winning and losing. Whether you push for pleasure or you are a pro athlete fighting the clock, you will benefit from running CeramicSpeed bearings.
CeramicSpeed bearings reduce friction and increase the longevity of the bearings. Your bike won’t just get faster – you’ll save time on changing worn out bearings; time you could be using on valuable training. Tests prove that you save 6 to 9 watts with CeramicSpeed bearings in your hubs, compared to a set of standard bearings.
|Distance||Time saving @48 km/h||Time saving @40 km/h||Time saving @32 km/h|
|40 km||25 sec.||50 sec.||2 min.|
|90 km||55 sec.||1:52 min.||4:30 min.|
|180 km||1:50 min.||3:45 min.||9 min.|
High quality ceramic products:
All the parts used in CeramicSpeed bearings are carefully selected from the highest quality suppliers. This allows them to create the ultimate performance bearings, which meet the demands of competitive athletes, and others who are seeking to optimise their performance.
The construction of the CeramicSpeed bearings is state of the art. The balls they use are of a unique quality, and have a super smooth surface, compared to both steel balls and other ceramic balls used for bicycles and wheelchairs.
This gives the bearings extreme impact strength, a superb longevity and very low friction.
The balls are kept in place by a reinforced polyamide cage. Balls and cages are matched (within microns) with the finest hardened steel raceways with an ultra-smooth polished groove. To this they add the optimised low-viscosity CeramicSpeed grease and no friction seals to keep water and dirt away from the balls.
Every single bearing is hand built in Denmark under laminar flow clean room conditions. Each bearing is inspected by hand four times during the building process to ensure that all parts are matched perfectly.
Ceramic balls are NOT all the same:
CeramicSpeed balls are Grade 3 Silicon Nitride with the highest achievable surface finish and roundness. 400% smoother, 128% harder and 58% lighter than the standard steel balls which are typically used in wheelchair and handcycle components.
Many ceramic bearings are generic industrial bearings, designed for high temperature (100-600C), high rotation speed (12,000-75,000rpm), corrosive, magnetic critical or explosive environments, where conditions, loadings are even and predictable. CeramicSpeed bearings are specifically designed for the high load, ambient temperature, low rotation speeds found in wheelchair and cycle sport.
The importance of ceramic grades:
Ceramic balls are available in different grades. The grade describes the smoothness and roundness of the ball. Ceramic balls are numbered from grade 3 upwards. The lower the grade, the smoother and rounder the ball is, with grade 3 being the best. The most common grades used in the bike industry are between grades 5 and 10, but some manufacturers use even higher grades.
|Grade||Sphericity [mm]||Lot diameter variation [mm]||Nominal ball diameter tolerance [mm]||Maximum surface roughness (Ra) [µm]|
CeramicSpeed uses only grade 3 balls. This is the key to achieving the lowest friction, and maximising longevity. This, combined with the production process of the balls, is why CeramicSpeed balls are 15% harder, 100% smoother and take 99% higher loads than other typical ceramic balls.
Smoother, harder and more resistant:
The CeramicSpeed balls are 15% harder, can stand 99% higher loads and are more than 100% smoother than other ceramic balls typically seen in the market. The hammer test video above speaks for itself. The smoothness and the hardness of the CeramicSpeed balls are unique. This smooth surface and consistent material prevents cracks or pits forming. After 600 hours of testing the CeramicSpeed ball is still in perfect condition whereas the surface of the other ceramic balls is rough and bumpy after only 10 hours of testing. The rough ball will create increased friction in the bearing and will quickly wear down the steel races. This friction will heat the ball, making it expand, jamming between the bearing races and causing more friction and heat.
This picture shows two ¼” (6.35mm) balls. The one to the left is a CeramicSpeed ball and the one to the right is a standard steel ball. We applied the same pressure to both balls and the result is clear. The steel ball simply cracked under the load while the CeramicSpeed ball is 100% intact and usable.
This picture shows a CeramicSpeed ball and a steel ball. Both have been running under the same conditions. The CeramicSpeed ball is in perfect condition and the steel ball has some corrosion. Both bearings work, but the operating temperature for the bearing with CeramicSpeed balls is lower. The lower the temperature – the longer the bearing will last.
This picture shows the same balls after some time in a corrosive environment. The CeramicSpeed ball has no sign of corrosion, while the steel ball is corroded and the bearing broke down before the test finished.
To illustrate the difference, we carried out an accelerated durability test of a randomly selected Chinese ceramic balls compared with a CeramicSpeed ball. The results speak for themselves. After only 10 hours, the Chinese ball failed while the CeramicSpeed ball was still in perfect condition after 600 hours!
The cheap Chinese balls are hard but brittle with a rough surface. They are harder than steel and in a bearing they would start grinding the steel races immediately. After a short time the races would be worn down and the bearing destroyed.
|Chinese ball after 10 hours of testing||CeramicSpeed ball after 600 hours of testing|
Ceramic material selection:
While many cheaper ceramic bearings are also made from Silicon Nitride, there can be huge variations in the quality and execution of the material itself. We won’t even look at white zirconia oxide balls, designed for low load, high temperature and high rotation speeds.
These two pictures were taken using an optical microscope. When you look closely at the surface of a ceramic ball, you should see a solid homogenous colour all over the ball. Variations in the colour indicate porosity or impurities.
Pic. 1 shows the surface of a Chinese ball. It clearly shows the porous indications (white colour in dark field and dark colour in white field).
Pic. 2 shows the surface of a CeramicSpeed ball. It has the same colour all over and no signs of porosity.
CeramicSpeed wheel bearings versus steel:
This wheel bearing lifetime test was conducted in CeramicSpeed’s own laboratory. All tests are accelerated lifetime tests, and all parameters, including wheel, tire, speed, load on the wheel, drum surface etc. were kept constant throughout the tests. When riding their bearings we always recommend lubrication to obtain the best performance and lifetime. The CeramicSpeed bearings lasted at least 10 times longer, so they switched the test off…
Wheel bearing test – bearings without lubrication on a flat drum.
In a test to give some indication of the impact resistance, the wheels were run lubricated, but on a bump drum. Test stopped at 45.000 km. – 2 sets of wheels broken but bearing still running. 9 times longer than the steel bearings…
Wheel bearing test – bearings lubed with oil and tested on a drum which applies a continuous regular impact via an artificial bump.
CeramicSpeed vs. other ceramic bearings:
In this test they compared the durability of CeramicSpeed bearings to other ceramic wheel bearings. The test is a highly accelerated test where the bearings are being exposed to shock, lack of lubrication etc. in order to document the difference in quality and performance. The choice of raw materials does not only affect the friction in the bearings but also the lifetime.
CeramicSpeed bearings run 1.5 to 4 times longer than any other ceramic bearings without any wear or damage.
Maintenance of CeramicSpeed bearings:
Contrary to popular opinion, all bearings need maintenance. How often you need to maintain your bearings will vary greatly, depending on a number of factors – including your racing discipline, the climate you ride in, and the way you clean your chair or handcycle. We recommend that you perform routine maintenance on your wheel bearings at 5-10,000 km intervals, or at least once per year.
If your equipment is exposed to extreme conditions or usage, then it can be an advantage to perform maintenance more frequently. Exact maintenance intervals will vary depending on the environment you are riding in.