At the Eurobike exhibition they showed a transmission for the bicycles of the future. There is no chain, there is only one sprocket on the rear wheel, and most importantly, there is almost no friction and associated losses. The creators claim that they have achieved an efficiency one and a half times higher than in current solutions for cycling professionals.
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The company reinvented the wheel CeramicSpeed : in her concept, the energy from pedaling at rear wheel transmitted by a rotating shaft rather than a traditional chain.
The company claims that this method of spinning wheels is one and a half times more efficient than the advanced traditional solution for professionals - Shimano Dura Ace cassettes and shifters. One of the creators of the system, Jason Smith, in an interview with Bikeradar explains This is a colossal reduction in friction points. And also with careful selection of bearings and lubricants - the company was helped in this by the Colorado laboratory Friction Facts.
“Every time the chain is tensioned, friction occurs. Each time it weakens, friction occurs. When you pedal at 95 rpm, there are 40,000 of these spots per minute,” Smith points out.
According to him, the rotating shaft through which energy is transmitted is a very traditional concept. For example, in a car differential, wheel speed is compensated using bevel gears. With this approach, there are only four friction points. But all attempts to adapt the mechanism for use in bicycles failed due to enormous friction. So the creators of the new transmission discarded the bevel gears and began to invent a different method of “perpendicular” force transmission.
The solution was a circle of bearings that rotates one “star” - and not five to seven, as on current bicycles, where the chain must be thrown in order to vary the forces.
The new product was shown in action at the Eurobike exhibition. According to Smith, friction losses were reduced to just 2%. However, Bikeradar indicates that the system is most effective at medium power levels - up to 300 watts.
CeramicSpeed recognizes that its solution has a long way to go from prototype to mass production. Firstly, the device does not yet know how to change gears. To do this, it is necessary to supplement the rod with a mechanism that moves the “sun” from the bearings along the “asterisk”. But this, according to the creators, is not difficult. More importantly, a special frame must be released for the new system - which means that for the bicycle revolution it is necessary to attract the attention of large manufacturers. Third key point- protection of precision bearings from road dust, dirt and moisture. In the demo prototype, where it was important to show how the system works, its internals are open to all winds.
If CeramicSpeed can overcome these challenges, perhaps the time trial bikes at one of the next Tour de France cycling events will look something like this:
In big Hi-Tech+ wrote about another trend in rethinking bicycles - compact electric motors that allow you to travel huge distances or easily overtake competitors.
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A bicycle with a cardan drive provides torque directly through the shaft, rather than a chain mechanism. The shaft drive was invented more than a hundred years ago. The most complex technology and the inadmissibility of switching gear ratios did not allow the invention to achieve good continuation. With the advent of the 21st century, technological techniques began to develop, then gear ratio Specifically, the chain drive was compared with the mechanics of internal bushing gearboxes. As a result, the market has somewhat replenished with serial bikes equipped with shaft drives.
How ideas developed
The idea of creating such drives without a chain appeared at the end of the 19th century. In addition to the shaft, there were completely variants of the chain, which never received further distribution. The first devices were developed in 1890 simultaneously by the United States and Great Britain. England was skeptical about the shaft drive, which is where it ended up in the American company Pope Manufacturing Company, which bought the rights to develop a unique device in the states.
Shaft drives began production from the League Cycle Company. After a short time, French developers released the first bicycle without a chain, which soon began to be mass produced.
Technical support
Gears are switched by a drive shaft connected to an internal bushing gearbox. Among modern manufacturers Sturmey-Archer, along with Shimano and, directly, SRAM, are considered the largest bicycle manufacturers with cardan drives.
Thanks to bevel gears, the rotation of the torque axis from the pedals is ensured mainly by 90 degrees. The rotational force is transmitted to the rear wheel by two pairs of bevel gears. The first pair is located in close proximity to the carriage shaft, the second is next to rear hub. The transmission is carried out in a Z-shape.
Bevel gears guarantee an optimal change in the angle of the felling axis, due to which there is less friction in contrast to worm gears.
A bicycle with a cardan is somewhat simpler and safer to use. When driving over rough terrain, the risk of chain jerking is eliminated. Because it is cleaner, the cyclist's clothing and the bike's chain do not become oily. The closed drive has a fairly long service life and is resistant to damage.
Seven main advantages of a gimbal bike
- Safe use for cyclists. There is no chance of clothing getting caught in the chain and jerking of the mechanism, since the cardan bicycle does not have a sprocket or oil chain.
- High reliability due to minimizing the number of moving parts.
- Durability ensured by the closed mechanism design.
- Low preventative maintenance requirements.
- Good aerodynamics.
- Increased distance between the bike frame and the road. A good distance is created due to the absence of a front sprocket.
- Originality of design.
- High cost.
Disadvantages of a shaft drive bicycle
- The structure weighs not so little - 1–3 kg.
- High cost.
- Difficult repair. In case of a breakdown, it is better to take the bike to a tire shop.
- The impossibility of compact implementation of a large number of gears, although their switching is considered smoother.
- The ride is somewhat stiffer than a chain bike.
Conclusion
A shaft drive bike is ideal for city riding as there is no need to special efforts on a flat road. Large quantity speeds when driving on asphalt are also not required. Acquisition unique bike once will allow you to use it in the future for a very long time.
CeramicSpeed unveiled a new rideless and silent ultra-performance bike at the world's leading bike show, Eurobike, in Germany this week. The prototype, called Driven, which literally captivated spectators, won the Eurobike award among 365 other nominees.
“Our goal was clear: to design the most efficient transmission imaginable. The bike's website claims that "in collaboration with the University of Colorado Department of Mechanical Engineering, a driveshaft concept has been created that uses 21 CeramicSpeed bearings and sets a new benchmark as the world's most efficient drivetrain."
The 21 CeramicSpeed Bearings system featured on the Driven bike consists of 21 bearings designed to enhance its functionality and efficiency. These bearings "transmit torque from front wheel to a 13-speed gear train mounted on the rear wheel.”
Control is carried out essentially through a system of driveshafts and gears, instead of the traditional and somewhat inefficient chain and derailleur models. The company claims that their new system“creates 49% less friction compared to the best systems chain drives that are on the market.”
The company achieved this by removing eight factors that contribute to friction. Additionally, replacing the metal chain with a carbon driveshaft resulted in a bike with a two-dimensional aerodynamic profile that reduces drag and allows for lower weight.
Even more impressively, CeramicSpeed conducted tests that showed that their Driven model achieved a 99% increase in peak efficiency over conventional bike models. The system was also found to provide 32% less friction than a CeramicSpeed optimized DA transmission and 49% less friction than Dura-Ace.
In fact, this is not the first model of this kind of drive that bicycle companies have experimented with. However, previous models have always demonstrated less power than in this case.
CeramicSpeed has only been working with the University of Colorado mechanical engineering department on their Driven bike for just nine months, and there's sure to be a ton more improvements to come. The team is already exploring integrating the driveshaft into the frame to further reduce wear.
The model still needs some work, but there's no doubt that CeramicSpeed is shaping up to be something truly remarkable. In fact, winning a Eurobike award is no small achievement. The award is considered one of the most prestigious in the cycling industry and "objectively evaluates the most advanced bicycle developments."
CeramicSpeed unveiled a new rideless and silent ultra-performance bike at the world's leading bike show, Eurobike, in Germany this week. The prototype, called Driven, which literally captivated spectators, won the Eurobike award among 365 other nominees.
“Our goal was clear: to design the most efficient transmission imaginable. The bike's website claims that "in collaboration with the University of Colorado Department of Mechanical Engineering, a driveshaft concept has been created that uses 21 CeramicSpeed bearings and sets a new benchmark as the world's most efficient drivetrain."
The 21 CeramicSpeed Bearings system featured on the Driven bike consists of 21 bearings designed to enhance its functionality and efficiency. These bearings "transmit torque from the front wheel to a 13-speed gear train mounted on the rear wheel."
Control is carried out essentially through a system of driveshafts and gears, instead of the traditional and somewhat inefficient chains and derailleurs. The company claims that their new system “creates 49% less friction compared to the best chain drive systems on the market.”
The company achieved this by removing eight factors that contribute to friction. Additionally, replacing the metal chain with a carbon driveshaft resulted in a bike with a two-dimensional aerodynamic profile that reduces drag and allows for lower weight.
Even more impressively, CeramicSpeed conducted tests that showed that their Driven model achieved a 99% increase in peak efficiency over conventional bike models. The system was also found to provide 32% less friction than a CeramicSpeed optimized DA transmission and 49% less friction than Dura-Ace.
In fact, this is not the first model of this kind of drive that bicycle companies have experimented with. However, previous models have always demonstrated less power than in this case.
CeramicSpeed has only been working with the University of Colorado mechanical engineering department on their Driven bike for just nine months, and there's sure to be a ton more improvements to come. The team is already exploring integrating the driveshaft into the frame to further reduce wear.
The model still needs some work, but there is no doubt that CeramicSpeed is developing into something truly outstanding. In fact, winning a Eurobike award is no small achievement. The award is considered one of the most prestigious in the cycling industry and "objectively evaluates the most advanced bicycle developments."
Photos from open sources
The bicycle, despite the desire of some to write it off as a thing of “yesterday,” does not want to leave the arena the most popular types transport, only acquiring more and more advanced qualities over time. Another novelty of this timeless bike is a design solution that eliminates the usual chain for a bicycle. This is precisely the unique property of the DrivEn concept, which was presented by CeramicSpeed at the Eurobike 2018 exhibition. (website)
Instead of the usual metal chain, this bicycle has a shaft, but not like a car or motorcycle, but light and flexible, made of carbon fiber. On both sides of this shaft there are special ceramic bearings, as well as teeth bent at 90 degrees, thanks to which it, rotating itself through the pedal, rotates the rear wheel of the bike.
Photos from open sources
Thanks to this design, the developers say, they were able to reduce friction (compared to a conventional chain, even the most advanced Shimano Dura Ace) by 49 percent. Friction is reduced due to the absence of eight points of contact from the chain transmission in this design (the place where the chain passes over the sprocket, cassette, derailleur).
Photos from open sources
The unique DrivEn bike has thirteen speeds and can demonstrate truly fantastic performance on a good track, while significantly saving the cyclist's strength. It is no coincidence that the new invention was immediately awarded the Eurobike Award, which was received by the developers of the University of Colorado.
And this, experts say, is just the beginning in the development of increasingly advanced chainless bicycles.
Photos from open sources
By the way, we note that the other day we wrote about what, and a rather modern design, was noticed in India in the 2000-year-old Panchavarnaswamy Temple, which can serve as indirect evidence that the design of a two-wheeled vehicle is so harmonious that it is not afraid of any technological progress, it is simply timeless. And this was once again proven by the developers of the DrivEn chainless bike (watch the video and admire the simplicity and genius of this solution).
