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44-411: The Speedhub is more expensive than competing bicycle gear systems (both hub gears and derailleur gears ), and it is some 100 grams heavier than a comparable set of derailleur gears, but offers about the same gear range (and at its ratio of 5.26:1 more range than a typical road bike ratio of 4.28:1 with 50/34 chainrings and 11 to 32 tooth cassette) while requiring significantly less maintenance and having

88-403: A parallelogram mechanism to keep the cage properly aligned with the chain as it swings back and forth. The other end of the arm mounts to a pivot point attached to the bicycle frame . The arm pivots about this point to maintain the cage at a nearly constant distance from the different sized sprockets. There may be one or more adjustment screws that control the amount of lateral travel allowed and

132-408: A battery pack and to a small electric motor that drives the derailleur. Although expensive, an electronic system could save a racing cyclist time when changing gears. The three main manufacturers of derailleurs are Shimano (Japan), SRAM (USA), and Campagnolo (Italy). The rear derailleur has two functions: it moves the chain between rear sprockets while taking up chain slack caused by moving to

176-472: A cable-shifted derailleur. In 1949 Campagnolo introduced the Gran Sport, a more refined version of the already existing, yet less commercially successful, cable-operated parallelogram rear derailleurs. In 1964, Suntour invented the slant-parallelogram rear derailleur, which let the jockey pulley maintain a more constant distance from the different sized sprockets, resulting in easier shifting. Once

220-399: A cage that holds two pulleys that guide the chain in an S -shaped pattern. The pulleys are known as the jockey pulley or guide pulley (top) and the tension pulley (bottom). The cage rotates in its plane and is spring-loaded to take up chain slack. The cage is positioned under the desired sprocket by an arm that can swing back and forth under the sprockets. The arm is usually implemented with

264-418: A compatible system of shift levers, derailleur, sprockets, chainrings, chain, shift cable, and shift housing. The major innovations since the 1990s have been the switch from friction to indexed shifting and the gradual increase in the number of gears. With friction shifting, a lever directly controls the continuously variable position of the derailleur. To shift gears, the rider first moves the lever enough for

308-422: A double planet system, all in even increments due to the cog sizes selected. The reduction gear is a standard unit known from the art. All planet gears of the first 2 planetary systems are on the same carrier (4 gears on each axle, with each set of 2 locked to the same shaft, i.e. 2 shafts rotating on a common axle). The common planet carrier is the means to transfer power between planetary system one and two. Input

352-462: A longer cage length. Typical cross country mountain bikes with three front chainrings will use a long cage rear derailleur. A road bike with only two front chainrings and close ratio sprockets can operate with either a short or long cage derailleur, but will work better with a short cage. Manufacturer stated derailleur capacities are as follows: Benefits of a shorter cage length: There are at least two methods employed by rear derailleurs to maintain

396-521: A longer service life. It is therefore mainly used in expensive touring bicycles and in mountain bikes , where its lack of (vulnerable) external components is useful. There are different options available for the Speedhub to cater for different kinds of bicycle frames and applications that the bicycle it is to be fitted to might be used in. Either of the above comes with the following three options: There also two types of axle available: As of 2014,

440-422: A particular derailleur. The actuation ratio is the ratio between the amount of shifter cable length and the amount of transverse derailleur travel that it generates. Shift ratio is the reciprocal of actuation ratio and is more easily expressed for derailleurs than actuation. There are currently several standards in use, and in each the product of the derailleur's shift ratio and the length of cable pulled must equal

484-414: A rear derailleur is known as the cage length. Cage length, when combined with the pulley size, determines the capacity of a derailleur to take up chain slack. Cage length determines the total capacity of the derailleur, that is the size difference between the largest and smallest chainrings, and the size difference between the largest and smallest sprockets on the cogset added together. A larger sum requires

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528-436: A smaller sprocket at the rear or a smaller chainring by the front derailleur. In order to accomplish this second task, it is positioned in the path of the bottom, slack portion of chain. Sometimes the rear derailleurs are re-purposed as chain tensioners for single-speed bicycles that cannot adjust chain tension by a different method. Although variations exist, most rear derailleurs have several components in common. They have

572-410: Is a variable-ratio bicycle gearing system consisting of a chain , multiple sprockets of different sizes, and a mechanism to move the chain from one sprocket to another. Modern front and rear derailleurs typically consist of a moveable chain-guide that is operated remotely by a Bowden cable attached to a shifter mounted on the down tube , handlebar stem , or handlebar . When a rider operates

616-408: Is achieved by allowing ring gear 3 to freewheel in a forward direction. It will thus either freewheel relative to the axle when final reduction is enabled, or to the sun gear when final reduction is in direct drive. In other words, when the final reduction stage is in direct drive, the freewheeling contribution will put the planetary system into reverse overdrive with the planet carrier now the input and

660-494: Is applied to the first ring gear. Either sun gear 1 or 2 must be locked to serve as reactionary member (but never both). With the planet carrier the output of the first system, the result is speed reduction. With the planet carrier the input of the second system and its ring gear (ring gear 2 of the mechanism) the output, the result is speed increase. Because a system consists of two suns of different size, two ratios each for reduction and increase are selectable. The second ring gear of

704-413: Is offered with different numbers of teeth, like 13/15/16/17. The 15-, 16-, and 17-tooth sprockets are reversible, offering double sprocket life once the sprocket is worn out in one direction. The 13-tooth sprocket is non-reversible and has a 4 mm outward offset, changing the chain-line from 54 to 58 mm, this because the smaller sprocket makes the chain run closer to the axle, and the chain would rub

748-405: Is provided with a twist shifter for shift operation, with one cable pulling in each direction. The indexing mechanism is part of the hub. As with all hub gears, there is a torque reaction that must be countered if the internals are not to rotate, and this is routed to the bicycle's frame by means of specially designed wheel dropout slots (OEM versions), or a torque bar bolted to the frame (EX) or

792-590: Is the Protean two-speed derailleur available on the Whippet safety bicycle. The French bicycle tourist, writer and cycling promoter Paul de Vivie (1853–1930), who wrote under the name Vélocio , invented a two speed rear derailleur in 1905 which he used on forays into the Alps . Some early designs used rods to move the chain onto various gears. 1928 saw the introduction of the "Super Champion Gear" (or "Osgear") from

836-483: The chain stay : this is called chain slap and can damage the chain stay. Clutches are also helpful in preventing the chain from derailing from the chain ring on systems without a front derailleur. The front derailleur only has to move the chain side to side between the front chainrings, but it has to do this with the top, taut portion of the chain. It also needs to accommodate large differences in chainring size: from as many as 53 teeth to as few as 20 teeth. As with

880-404: The freewheel in the crankset so that the chain moves even when the rider is not pedalling. The Shimano FFS (Front Freewheel System) circa 1980 was the most widespread such system. Chain-drive systems such as the derailleur systems work best if the chain is aligned with the sprocket plane, especially avoiding the biggest drive sprocket running with the biggest driven sprocket (or the smallest with

924-404: The gearing mechanisms and select the desired gear ratio . Typically, they operate either a derailleur mechanism or an internal hub gear mechanism. In either case, the control is operated by moving a cable that connects the shifter to the gear mechanism. Traditionally shifters were mounted on the down tube of the frame or stem . For ergonomic reasons, they tend to be located somewhere on

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968-414: The Speedhub is available in three colours: silver, red or black. Finally, the Speedhub is available with either 32 or 36 spoke holes. The above options are combined so a particular unit could be a Speedhub "CC DB OEM2 silver, 32 spoke holes" or a Speedhub "TS EX OEM black, 36 spoke holes" for example. The internal construction of the gear hub consists of three planetary gear series, connected one after

1012-429: The appropriate gap between the upper jockey wheel and the rear sprockets as the derailleur moves between the large sprockets and the small sprockets. One method, used by Shimano, is to use chain tension to pivot the cage. This has the advantage of working with most sets of sprockets, if the chain has the proper length. A disadvantage is that rapid shifts from small sprockets to large over multiple sprockets at once can cause

1056-433: The cage to strike the sprockets before the chain moves onto the larger sprockets and pivots the cage as necessary. Another method, used by SRAM, is to design the spacing into the parallelogram mechanism of the derailleur itself. The advantage is that no amount of rapid, multi-sprocket shifting can cause the cage to strike the sprockets. The disadvantage is that there are limited options for sprocket sizes that can be used with

1100-409: The center axle and will overrun when one of the sun gears is locked and power is transmitted to the ring gear by the planets. In other words, ring gear 2 can either rotate at the same speed as the shared planet carrier or at a higher speed. Clutch #3 couples the reduction stage sun gear to its ring carrier (direct drive), clutch #4 locks the reduction stage ring gear to the stationary axle. Freewheeling

1144-642: The chain to jump to the next sprocket, and then adjusts the lever a slight amount to center the chain on that sprocket. An indexed shifter has a detent or ratchet mechanism which stops the gear lever, and hence the cable and the derailleur, after moving a specific distance with each press or pull. Indexed shifters require re-calibration when cables stretch and parts get damaged or swapped. On racing bicycles , 10-gear rear cassettes appeared in 2000, and 11-gear cassettes appeared in 2009. Most current mountain bicycles have either. Many modern, high-end mountain bikes have begun using entirely one chain ring drivetrains, with

1188-789: The company founded by champion cyclist Oscar Egg , as well as the Vittoria Margherita* both employed chainstay mounted 'paddles' and single lever chain tensioners mounted near or on the downtube. However, these systems, along with the rod-operated Campagnolo Cambio Corsa were eventually superseded by parallelogram derailleurs . In 1937, the derailleur system was introduced to the Tour de France , allowing riders to change gears without having to remove wheels. Previously, riders would have to dismount in order to change their wheel from downhill to uphill mode. Derailleurs did not become common road racing equipment until 1938 when Simplex introduced

1232-423: The disc brake mount (DB). The hub contains 25 ml of oil which should be replaced once a year or after 5,000 km (manufacturer advice). Overfilling can lead to leaks, as can laying the hub/cycle on its side in some low-pressure aircraft holds. The sprocket on the hub is made for standard-pitch derailleur-type bicycle chains 1 ⁄ 2 by 3 ⁄ 32 inch (12.7 mm × 2.4 mm) (ISO 082) and

1276-497: The easier change to smaller sprockets. In road racing, the swiftest gear changes are required on the sprints to the finish line. Therefore high-normal types, which allow a quick change to a higher gear, remain the preference. Low normal or rapid rise rear derailleurs return the chain to the largest sprocket on the cassette when no cable tension is applied. While this was once a common design for rear derailleurs, it has become relatively uncommon. In mountain biking and off-road cycling,

1320-490: The hub shell if the sprocket were not offset. Rohloff hubs generally require a break-in period to function optimally. The manufacturer suggests this may require 500–1,000 miles (805–1,610 km) of active riding. For some riders the break-in period may be longer. Until the hub is broken in the rider may experience some noise or vibrations when the reduction-gear is in operation (gears 1–7). Derailleur gear A derailleur ( French pronunciation: [deʁajœʁ] )

1364-420: The industry constantly pushing the number of rear cogs up and up, as shown by SRAM's Eagle groupsets (1 by 12) and Rotor's recent 1 by 13 drive-train. Most road bicycles have two chainrings, and touring bicycles commonly have three. An electronic gear-shifting system enables riders to shift with electronic switches instead of using conventional control levers. The switches are connected by wire or wirelessly to

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1408-402: The lever while pedalling, the change in cable tension moves the chain-guide from side to side, "derailing" the chain onto different sprockets. Dérailleur ( [ d e ʁ a j œ ʁ ] ) is a French word, derived from the derailment of a train from its tracks. Its first recorded use was 1930. Various derailleur systems were designed and built in the late 19th century. One example

1452-405: The limits of lateral travel allowed. The components may be constructed of aluminium alloy, steel, plastic, or carbon fibre composite. The pivot points are usually bushings, and these will require lubrication. Because of the possibility of the chain shifting past the smallest inner chainring, especially when the inner chainring is very small, even on bikes adjusted by professional race mechanics, and

1496-494: The mechanism is directly bolted to the final sun gear of the reduction stage. When the final stage's ring gear is held stationary, the result is speed reduction at the planet carrier output. With planet carrier and ring gear of the final reduction stage locked (and the final ring gear free to spin), it gives direct drive and a reduction ratio of 1:1. Clutch #2 cannot be engaged. It is simply an overrun clutch that will be locked and transmit power when suns #3 and #4 are disengaged from

1540-410: The most critical gear changes occur on uphill sections, where riders must cope with obstacles and difficult turns while pedalling under heavy load. This derailleur type provides an advantage over high normal derailleurs because gear changes to lower gears occur in the direction of the loaded spring, making these shifts easier during high load pedalling. The distance between the upper and lower pulleys of

1584-613: The other being output). Shifting is achieved by locking a certain combination of suns, using pawls , and engaging or releasing each of the two clutches. The first planetary series gears three and two steps down respectively, while the second gears two and three steps up respectively, both also having direct drive when the respective clutch is engaged with the suns free to spin. One step down is achieved by combining three steps down with two steps up, and one step up by combining two steps down with three steps up. Thus three different steps down, direct drive and three different steps up are achieved by

1628-500: The other, selectively engaged depending on the user's gear choice, each containing a stepped planet. The first two gear series provide seven ratios, and the third a complete range reduction, doubling the number of speeds to fourteen. The first two stepped series are identical and mirrored, each offering two ratios and direct drive. Each planet level meshes with a sun gear (each of which can be either stationary or free to rotate), and each smaller planet meshes with an annulus (one being input,

1672-412: The patents expired, other manufacturers adopted this design, at least for their better models, and the "slant parallelogram" remains the current rear derailleur pattern. Before the 1990s many manufacturers made derailleurs, including Simplex , Huret , Galli, Mavic , Gipiemme, Zeus, Suntour, and Shimano . However, the successful introduction and promotion of indexed shifting by Shimano in 1985 required

1716-405: The pitch of the rear sprockets. The following standards exist. Shifters employing one convention are generally not compatible with derailleurs employing another, although exceptions exist, and adaptors are available. Some rear derailleurs, especially for mountain bikes, incorporate a clutch to keep the lower length of chain in sufficient tension to prevent the chain from striking the bottom of

1760-466: The problems such misshifts can cause, a small after-market of add-on products, called chain deflectors, exists to help prevent them from occurring. Some clamp around the seat tube, below the front derailleur, and at least one attaches to the front derailleur mount. Derailleurs require the chain to be in movement in order to shift from one ring or sprocket to another. This usually requires the rider to be pedalling, but some systems have been developed with

1804-403: The rear derailleur, the front derailleur has a cage through which the chain passes. On a properly adjusted derailleur, the chain will only touch the cage while shifting. The cage is held in place by a movable arm which is usually implemented with a parallelogram mechanism to keep the cage properly aligned with the chain as it swings back and forth. There are usually two adjustment screws controlling

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1848-417: The ring gear the output that has no load. The IGR (inner gear ratio), hub revolutions per sprocket revolution of the Speedhub, lies between 0.279 and 1.467 depending on the gear chosen. Gear 11 has a ratio of 1.0. The Speedhub has a 526% range between the highest and lowest gear. The range of gears in detail is: The overall average loss of the gears is about 1%–5%, comparable to a derailleur. The Speedhub

1892-417: The smallest). The diagonal chain run produced by these practices is less efficient and shortens the life of all components, with no advantage from the middle of the range ratio obtained. Derailleur gears generally have an efficiency around 95%, a few percentage points higher than other gear types. Twist shifter A bicycle shifter or gear control or gear levers is a component used to control

1936-527: The spring tension. The components may be constructed of aluminium alloy , steel , plastic , or carbon fibre composite. The pivot points may be bushings or ball bearings . These will require moderate lubrication. High normal or top normal rear derailleurs return the chain to the smallest sprocket on the cassette when no cable tension is applied. This is the regular pattern used on most Shimano mountain, all Shimano road, and all SRAM and Campagnolo derailleurs. In this condition, spring pressure takes care of

#4995