Planetary gear cycling pros and cons

What it is

An internal hub is a sophisticated shifting system for a bicycle. It is more reliable and durable than a regular hub, but it reacts very badly to overload, so they are not used in competitions or extreme riding. The most advanced models (for example, some Dutch bikes) have 7-stage planetary hubs, while simplified city bikes (or folding ones) have 3-stage ones. In such bushings, the mechanism and stars are lubricated under a protective shell, and the system itself resembles a car gearbox.

The patent for the planetary hub dates back to 1880. For the first time, such bushings were used on three-wheeled motorcycles. In 1895, a compact 2-speed planetary hub was invented by an American engineer, which did not find success in the market. Already at the beginning of the 20th century, the number of speeds increased to 3 (by Sturmey-Archer).

In the 1930s, the market was full of planetary gears, almost every bicycle had such a hub (they were especially popular in Great Britain, Holland, Germany, Scandinavia). Later, there were speed switches and cassettes mounted on bushings. Due to its low cost and unpretentiousness, such a system soon replaced the planetary bushings.

  • Sun gear: located in the center (green in the picture). this is the axis of the wheel.
  • Carrier: rigidly fixes the axes of several planetary gears (satellites) of the same size, which mesh with the sun gear (blue).
  • Ring gear (epicycle): external gear, internally meshed with planetary gears (red). driven by a chain.
  • Planetary gear in high speed mode. The carrier (blue) is rotated by an external source. The force is removed from the sun gear (green) while the ring gear (red) is fixed. Red marks indicate 45 ° rotation of the input shaft.
planetary, gear, cycling, pros, cons

Features of the

The peculiarity of planetary bushings is higher cost and lower maintainability than a classic shift system. A sophisticated shifting mechanism inside the hub is more expensive than a classic shifting system.

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The planetary hub is reliable, with proper operation, the resource is tens of thousands of kilometers. The drive uses thick chains and sprockets, and their service life is many times longer than that of comparable bike components with a classic derailleur. The planetary transmission does not require maintenance, the only adjustment is the cable tightening during operation. However, if something breaks in the planetary hub, the repair can be expensive and will have to be done in a specialized workshop.

Despite the large number of speeds in the most advanced models, not all types of riding will have enough planetary hub speeds. Such a gearshift system is suitable for unhurried, comfortable riding in the city, forest and parks. But if we are talking about cross-country riding or more extreme cycling, then the number of speeds and gear range will not be enough.

Comparison with standard cassette

The most common variant is the classic cassette and derailleur switching scheme. The rear hub has a set of sprockets called a “cassette” and an external derailleur attached to the frame via an adapter called a “cock”. On multi-speed bikes (over 7 speeds), there are also two or three chainrings in front and an external front derailleur.

The total number of gears is the number of stars in the front system multiplied by the number of stars in the rear cassette. For example: 3 forward and 9 reverse gears add up to 27 speeds. But in fact, it is impossible to use all combinations and is even contraindicated, since it will lead to premature wear and equipment breakdown. To avoid distortions of the chain, thereby eliminating the likelihood of breakage, it is usually recommended to use such combinations as: 1 × 1,2,3, 2 × 2,3,4,5,6,7,8, 3 × 7,8,9.

The classic circuit with switches is the most common and affordable. A suitable system or individual spare parts can be selected. The main plus is that it is easy to repair it if it breaks down or to upgrade to a more advanced one. But there are also a few drawbacks: the rear derailleur is attached to the right side of the frame and is easy to break if the bike falls unsuccessfully on its right side.

Also, the system is demanding on cleanliness, since all components are open, it is necessary to clean the components and lubricate the chain in order to exclude its premature wear. It is necessary to learn how to change gears correctly. in no case should you switch under load. It is always necessary to change gears in advance and at the time of shifting it is necessary to press on the pedals not hard to avoid breaking the chain. This shifting system is not compatible with the rear foot brake.

Advantages and disadvantages

  • The gearshift mechanism is completely hidden inside the rear wheel hub housing to protect it from dirt. Due to this, the durability of the parts is significantly increased.
  • It is possible to change gears even when you are standing still.
  • Chains and sprockets of regular width are used (for single speed bicycles). The chain runs straight all the time. Sprockets with a high tooth profile are used. All this affects the increase in the resource of chains and sprockets.
  • The gearshift mechanism and the built-in brake in such systems are maintenance-free, which simplifies the operation of the bike.
  • Long service life of bushings, parts of which work in an oil bath.

The biggest drawback of multi-speed planetary hubs is their heavy weight: they are two to four times heavier than conventional mountain bike rear hubs. True, it should be noted that there is no need for a number of transmission parts, such as gear shifters, so that the real difference in weight is not so great.

The complex gear mechanism has a sufficiently high friction, which leads to a reduced efficiency. These properties became the defining factor for the elimination of the use of such hubs on sports bicycles. Planetary hubs are still not designed to work in extreme conditions and, moreover, they are almost not repairable anywhere except for a specialized bike service.

Planetary hub bikes are made for the most enjoyable city walks. These bikes have many advantages, one of which is the ability to develop high speed. The presence of a planetary hub on the bike assumes an even distribution of the load, which makes it possible not to get tired, even if you are on a trip for a long time. Easy gear shifting ensures ease of use of the bike, and most importantly, it can be done right in the direction of travel. Equipment from renowned manufacturers, rim brakes, protection against dust and dirt make the bike an ideal means of transportation in the conditions of domestic roads.

How does “planetary” work

The transmission functionality works by connecting the rear sprocket to an external gear or sun gear through a bushing, depending on the position of the switch. Increasing or decreasing the transmission is carried out through the cage of satellites. When lowering is required, the sprocket turns the epicycle, which, when meshed with the planetary gears, causes them to rotate around the axial gears. To increase, on the contrary, the revolutions of the star are transmitted through the cage to the external gear wheel.

Planetary bike hub: performance features, pros and cons

Another convenience of the planetary hub is that gear changes can be performed without pedaling: on the contrary, it is recommended that the chain be stationary. This is very similar to a gearbox in a car, where you must release the clutch before moving the lever to a new position. In this case, the chain does not jump between the stars, which excludes the possibility that it will fly off while moving.

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Advantages and disadvantages of the planetary gear

The main advantage of such bushings is that they are absolutely not afraid of dirt and therefore do not need that constant care, without which ordinary cassettes from stars cannot do. Also, fans of this type of transmission are attracted by the fact that there are no unnecessary details. the hub itself, two sprockets (on the pedals and on the rear wheel), a chain and a derailleur with a flexible cable. That is, it will be much more difficult to break such a system than a cassette.

Another definite plus. less chain wear. The fact is that on a standard multistage transmission, the transmission has four bends (around the sprockets and through the tensioner), which increases the load on the links. In addition, the chain periodically changes its position in the plane of rotation, which also leads to increased friction against the teeth and wear. When installing the planetary hub, the transmission works only around two sprockets without additional bends.

The disadvantages include a rather heavy weight added to the rear wheel, although when carrying the bike over an obstacle, the increase in load will remain imperceptible. Excess weight will affect only when climbing a steep slope. If a bike you are used to has a high cadence (cadence) to wheel rpm ratio, the planetary system’s capabilities may seem inadequate. For star cassettes, this ratio from lowest gear to highest is about 550%, which means a difference in distance traveled. Hubs with satellite clips have a lower percentage. about 300% for mechanisms at 8-11 speeds.

planetary, gear, cycling, pros, cons

Bushing manufacturers

The main manufacturers of these devices can be distinguished:

  • Shimano;
  • SRAM;
  • Sturmey-Archer;
  • Rohloff

The second place in production is occupied by SRAM. Models from this manufacturer have up to 12 speed gears. Their gear range reaches up to 420%.

Sturmey-Archer is a manufacturer of hybrid planetary cassette hubs. In addition, this company produces other types of bushings with speeds 3, 5 and 7.

Disadvantages of planetary bushings

In addition to the advantages, these devices have some disadvantages:

  • Great weight. Unlike conventional hubs, these elements are quite heavy, for example an average planetary hub with a seven-speed transmission weighs about 1.7 kilograms;
  • Inability to use on sports bicycles. Due to the fact that these bushings have high rolling friction;
  • Complex construction. If you find any breakdowns and malfunctions, you do not need to fix them yourself, it is best to contact a specialist;
  • High price;
  • Strong and aggressive driving increases the risk of gear breakage.

Benefits of using planetary hubs

Depending on the properties and functions of the planetary bushings, the main advantages of these devices can be distinguished:

  • High strength and durability. The mechanism of this device is located under the protective casing. In addition, it provides complete lubrication of all elements with transmission oil;
  • Fast and precise gear shifting of speed. Due to the fact that the switch is located on the handlebars of the bicycle, you can switch the speed while standing still;
  • High set of gear ratios. For example, if a bicycle has a set of 42-32-32 stars and an 11-30 cassette, then its gear ratio can reach up to 520%. It’s also worth noting that seven-speed hubs can have a transmission range of up to 303%. During the ride, the load is evenly distributed, and therefore bicycles with these hubs can easily overcome various bumps and bumps;
  • Simple and durable chains. Thanks to these chains, uninterrupted operation is ensured, there are no distortions and displacement along the stars. In addition, these elements significantly increase the wear and tear of the entire drive system.

Planetary hub device

The working process of the planetary hub is the same as that of a car gearbox. speed regulation. During the ride, there are no difficulties and unforeseen problems. With the help of this device, fast and timely switching of speed modes occurs. The figure shows the complete structure of the mechanism of this device.

Elements included in the planetary hub device:

  • Sun gear (yellow). It is located in the central part of this device, and serves as the axle of the rear wheel;
  • Carrier (blue). This is a group of several planetary gears or satellites, which are very firmly fixed on their axles and are firmly fixed with the sun gear;
  • Ring gear (red). This is an outer gear or epicycle. It consists of an internal gear train. This transmission provides a strong hitch with the satellites.

Repair and maintenance of planetary hub

Planetary hubs rarely break. They have a very long service life and are very durable. Of course, if the rules of use are not followed, sometimes the mechanism of these devices may fail, then it is best to contact specialists to troubleshoot.

Application area of ​​planetary bushings

Therefore, it is better to install it on bicycles for city riding, because these bicycles do not meet heavy loads and are used mainly for smooth roads.

Planetary hub on a bike. what it is?

Today, two different gear shifting systems can be distinguished. external and internal switching.

External. rear derailleurs familiar to us;

Internal. less common solution, but actively gaining ground. The most common solutions are easy to find on bicycles in our catalog are Shimano hubs: Nexus, Alfine, etc. Their main purpose. walking skiing. Most often seen on city and folding bikes.

The planetary hub mechanism is very complex and has several dozen parts in its design. All this is in a closed case and the general system of operation is similar to a car gearbox, where the gears have different gear ratios.

For example, here she is on a bike from Polygon

There are also a number of planetary transmission solutions in other implementations, but this is a topic for a separate article. Pictured Pinion.

The first patent for a planetary hub is dated 1880. The English company Sturmey-Archer appeared on the market (today it belongs to SunRace). The first 2/3 speed bushings date back to 1902! Today there are already 3/5/8-speed models. A little later, the Sachs company (now owned by Sram) in 1904 offered the world its version. Today they are available in 3/5/7 speed versions.

Shimano’s third bulk supplier with 3-, 7- and 8-speed hubs.

The maximum number of gears reached by the planetary hubs. 14. Brand name. Rohloff Speedhub 500/14. At the same time, the total shift range is 526%, which is as close as possible to a modern mountain bike. However, solutions from Rohloff, although reliable, are extremely expensive for the mass segment.

  • Straight chain travel and low wear on the drive and driven sprockets. From the outside, everything looks like a 1 speed bike. Nothing sticks out;
  • High strength and reliability. The bushing is maintenance-free for its entire service life. It is enough to tighten the cable from time to time. Everything is hidden inside the case, in which all elements are constantly lubricated;
  • Gear shifting in place. No need to pedal;
  • There is no risk of the cock breaking and the derailleur getting into the spokes.
  • Smaller gear ratio. Mountain bikes have this figure of 550%, while regular Shimano Inter has only 306%. Such indicators are not enough for mountainous terrain;
  • Cannot be used in sports due to high friction and sensitivity of gears;
  • The overall efficiency is lower due to the large number of elements;
  • weight;
  • If, nevertheless, something breaks, then repair is almost impossible;
  • Price.
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Yes. Most mountain bikers in the city, most of them use only 5 of the entire drivetrain. Therefore, for normal riding, a planetary hub will be enough for you.

For everyone who chooses a bike up to 80,000 rubles. here is a plate from our article about the characteristics of bicycles. What sleeve is it for?

Planetary gear cycling pros and cons

Choosing a bike with several speeds, the buyer is often faced with a variety of incomprehensible terms. In this article we will try to deal with the issues of gear shifting and the “planetary hub”.

There are currently two types of gear shifting: the classic scheme with derailleurs and the planetary hub.

Planetary hub. closed gearshift system for the bike, the whole mechanism is inside the rear hub. The design is reliable and durable. Simple planetary hubs have 3 speeds, the most advanced models have up to 14 gears.

Planetary hubs were most popular in the first half of the 20th century, almost every bicycle had such a hub (they were especially popular in Great Britain, Holland, Germany, Scandinavia). However, the speed switches and cassettes that appeared later replaced the planetary hubs, due to their low cost and unpretentiousness.

The planetary hub bike does not have an external derailleur. the entire shifting mechanism is hidden inside the rear hub, and outside there is only one sprocket and chain. This is the most important advantage of planetary hubs. there are no unnecessary parts that are so easy to damage if dropped. The entire shifting system is located inside the hub body, reliably protected from dirt and external influences. Shifting can be done both under load and without, since the chain is in the same gears all the time, there is no probability of its damage when shifting. Unlike the classic shifting system, the planetary hub is compatible with the rear coaster brake.

The peculiarity of planetary bushings is higher cost and lower maintainability than a classic shift system. A sophisticated shifting mechanism inside the hub is more expensive than a classic shifting system.

The planetary hub is reliable, with proper operation, the resource is tens of thousands of kilometers. The drive uses thick chains and sprockets, and their service life is many times longer than that of comparable bike components with a classic derailleur. The planetary transmission is maintenance-free, the only adjustment is cable tightening during operation. However, if something breaks in the planetary hub, the repair can be expensive and will have to be done in a specialized workshop.

planetary, gear, cycling, pros, cons

Despite the large number of speeds in the most advanced models, not all types of riding will have enough planetary hub speeds. Such a gearshift system is suitable for unhurried, comfortable riding in the city, forest and parks. But if we are talking about cross-country riding or more extreme cycling, then the number of speeds and gear range will not be enough.

It is worth noting that the weight of the planetary hub is much higher when compared with the classic gear system, the weight distribution of the bike will be shifted towards the rear wheel.

long resource with proper operation

the gearshift mechanism is completely enclosed in the hub housing to protect it from dirt

Compatible with both hand brakes and rear coaster brakes

If you need a bike for a quiet ride in the city and parks, you do not chase the number of gears and want to have a reliable bike without unnecessary parts and easy to use, then the planetary hub is exactly what you need.

The most common option. this is a classic switching scheme with cassette and switches. The rear hub has a set of sprockets called a “cassette” and an external derailleur attached to the frame via an adapter called a “cock”. On multi-speed bikes (over 7 speeds), there are also two or three chainrings in front and an external front derailleur.

The total number of gears is the number of stars in the front system multiplied by the number of stars in the rear cassette. For example: 3 forward and 9 reverse gears add up to 27 speeds. But in fact, it is impossible to use all combinations and is even contraindicated, since it will lead to premature wear and equipment breakdown. To avoid chain distortions, thereby eliminating the likelihood of breakage, it is usually recommended to use such combinations as: 1×1,2,3, 2×2,3,4,5,6,7,8, 3×7,8,9.

The classic circuit with switches is the most common and affordable. A suitable system or individual spare parts can be selected. The main plus is that it is easy to repair it if it breaks down or to upgrade to a more advanced one. But there are also a few drawbacks: the rear derailleur is attached to the right side of the frame and is easy to break if the bike falls on its right side unsuccessfully. Also, the system is demanding on cleanliness, since all components are open, it is necessary to clean the components and lubricate the chain in order to exclude its premature wear. It is necessary to learn how to change gears correctly. in no case should you switch under load. It is always necessary to change gears in advance and at the time of shifting it is necessary to press on the pedals not hard to avoid breaking the chain. This shifting system is not compatible with the rear foot brake.

Which gearing system is right for you?

If you follow the rules of switching, keep the bike clean and do the necessary maintenance in a timely manner, then the classic switching system will delight you with high-quality and reliable work.

If you choose a mountain bike or you need excellent maintainability, then there is only one choice. classic gearshift system.

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Planetary hub, variator, gearbox and more

Hello everyone! The velo-travel team is with you and today we will talk about bicycle gears. But we will not talk about shifters and cassettes. Today’s topic of conversation is gearboxes and variators on a bicycle. We’ll figure out a little with you what, why, where and most importantly, we will try to understand why now everyone uses a simple gearshift system, and not a gearbox.

Somehow in our groups, on social networks, we posted a post with a photo, which depicted the transfer of torque from the pedals to the rear wheel using the propeller shaft. The post was discussed enough, and something new.

The idea to install a gearbox on a bicycle appeared back in the distant 19th century. But this idea existed in blueprints and in thoughts until 1915. At that time, only planetary bicycle hubs were sold at a cost of £ 3. For our money, this is more than enough to go crazy. The weight of such a sleeve was over 3 kilograms. In the period from the 19th century until the Second World War, gears were changed using ineffective drive and frame systems.

This is what motivated us to create a compact gearbox for a bicycle. The first question that arose before the engineers was where to put it? It was decided unambiguously. near the carriage.

In 1935, a number of German manufacturers began producing a 3-speed bicycle gearbox, which was housed in a bottom bracket. The gearshift lever was located in the place where gear selectors were once installed on Soviet road bikes. at the top of the lower tube of the frame. A couple of companies produced gearboxes with only two gears. Perhaps these developments would have reached their logical conclusion and the massive transition of bicycles to gearboxes, but a war began that broke many plans and many lives

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What are the advantages of gearboxes of that time?

Protected against dirt and water thanks to well positioned.

Good weight distribution, again thanks to the positioning above the carriage assembly.

There were only a few downsides. a noticeable loss of power, which is why such boxes were not installed on road bikes, and the cost of making a gearbox wanted to be lower.

And so the war passed, a lot of time passed, and no one returned to improving the gearbox on a bicycle. Only in the early 90s, it was the development of the HH discipline that led to the modernization of gearboxes. As you know, during a quick descent from a mountain, the rear caliper constantly beats against the frame and does not change gears well. It was then that they began to come up with such a gearshift mechanism that would not be in the back and would perfectly perform its functions.

From the book “Modern Bicycle” we got the following information.

There were three main developments. the German company Nicolai, and the Japanese Hoda and SR Santur. The Germans installed an open-type gearbox based on a planetary hub. The drive had two chains, the inner chain transfers power from the connecting rods to the planetary gear, and the outer one from the planetary gear to the rear sprocket. Honda took Shimano components as a basis and created a bike weighing 18 kg and with 7 gears. An external chain spins the rear wheel, and a short chain moves the redesigned rear caliper across the cassette. Santur decided not to waste time on trifles at all and created a 9-speed gearbox weighing 4.5 kilograms, which resembled a miniature car gearbox.

The bottom line is that the developments are interesting, but expensive and made in small quantities. The book says: “But if it goes” and it was about the year 2000. Now we can safely write in 2015. it didn’t go well.

And so, so far, transmissions have ceased their development. And what then came to replace them?

This is something similar to a planetary hub, only located in the carriage

There is a lot of detailed information about the development of planetary carriages with exact dates and numbers. We do not want to load ourselves and you with this information, so we will tell you the most interesting.

The main goal of the planetary carriage was compactness and the multiplier. The weight of the developments ranged from 1200 grams to 2000 grams with the connecting rods. There were developments of the Nikolay company, which had a magnetic gear change drive.

The main disadvantage of all developments was the incompatibility of the dimensions of the planetary carriages with the standard dimensions of the carriages. But the pros are also visible on the face. Firstly, you do not have to pedal to change gear, and secondly, the small chainring allows you to install a rear caliper with a short foot. These calipers are known to be more resistant to impact and wear. Thirdly, such a phenomenon as chain skewing practically disappears, which means that the service life of the chain itself increases.

Still, the planetary carriage is an interesting development, but it was the planetary hub that received the greatest success, which we will describe below.

The story goes that the first modern planetary hub was born back in 1898, can you imagine? Personally, we find it hard to imagine. The hub had a built-in braking mechanism and several gears. Further developments went up and bushings with 3 gears appeared. Faster and more successful hubs began to appear towards the beginning of the 20th century. One of the most famous manufacturers is Sachs Bicycle Component, now this company is part of the SRAM corporation. It was the production of planetary hubs that turned the velom around a bit and excluded the production and development of other types of internal gear shifting.

There are now planetary hubs in 3, 5 and 7 gears. If about 5 years ago there were only ordinary bushings, so recently planetary bushings with a disc brake and with a built-in brake have already been widely settled on the market. And one more difference between the old bushings and the new ones is the compatibility with the front derailleur. And recently. and with the installation of a cassette on the rear wheel. That is, you have, as it were, the usual 3×8 gears and also a planetary gear in 3 speeds. And yet, for comparison. The gear range of a standard 3×7 shifting system is around 500%, and some Rohloff 14-speed hubs have a whopping 600%. Cool isn’t it?

Brief advantages of planetary hubs:

Large range of gear ratios, which we wrote about above.

Ease and smoothness in gear shifting.

Easy to maintain and eliminate the need for constant maintenance.

And also a few cons:

Planetary hubs are mainly used in city bicycles. It is convenient and simple. Cardan drive for transmission of torque.

The advantages of a cardan shaft over a chain are enormous, and it is very strange that now this type is not used. Main advantages:

Does not stain clothes or cling to the leg.

The efficiency indicator is not higher, but independent of the amount of dirt and swamp on the gimbal.

Understanding PLANETARY GEAR set !

The cardan broke a little, but, like the planetary, it required separate knowledge in repair.

Inability to set gear shifting.

Modern developments were able to eliminate a number of the above disadvantages, especially the problem with gear shifting. the installation of a planetary hub made it possible to change gears.

The belt drive was used for a very long time and eventually stopped, because the main disadvantage is insufficient strength and slippage. But again, science and engineering do not stand still and today there is a clear competition between belt and chain drives. The main disadvantage of the belt is its integrity, the impossibility of installing gear switches and the complexity of repair and replacement of components.

The advantage of the variator is the stepless gear shifting and the possibility of a large gear range. But the disadvantages, unfortunately, are significant. The most important thing is low efficiency, due to slippage in the variator itself. The disadvantages also include the loss of power, the cost.

CVTs are now starting to regain popularity due to advances in technology and the sleepless nights of engineers. The weight of the bushings used to be about 5 kilograms, but now the impetus drops to 3. Let’s see what will come of this in a few years, so far only one thing is clear. the CVT will have a future.

And so, and now let’s try to understand why all these developments did not take root? So much new, so much interesting, but everything remains: the chain and transmissions. Do you know why? And because all ingenious is simple. Everyone loves the bike for its simplicity. And there is no need to complicate anything. Two wheels, a frame, brakes and a steering wheel, what else do you need? That is why, before upgrading your bike, think carefully if you need it, and whether it will be useful in cycling.