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| {{Short description|Tool for disassembling and assembling bicycle chain}} | |||
| ⚫ | |||
| {{Unreferenced|date=December 2011}} | |||
| {{Infobox tool | |||
| | name = Chain tool | |||
| | image = | |||
| | caption =A bicycle chain tool | |||
| | other_name = | |||
| | classification = ] | |||
| | types = | |||
| | used_with = | |||
| | inventor = | |||
| | manufacturer = | |||
| | model = | |||
| | related = | |||
| }} | |||
| ] | |||
| ⚫ | A '''chain tool''' is a small mechanical device used to "break" a ] in such a way that it can be mended with the same tool. A bicycle chain has links and plates that are pinned together; these pins can be pushed out with the chain tool. Because the pins are pushed out gradually with a screw, they can be partially removed or fully removed, depending upon the intention of the user. | ||
| ⚫ | The chain tool has two positions where a chain can be inserted perpendicular to the tool, one close to the movable screw portion, and one lower down just above the fixed end. In each position, there are a pair of protruding tabs; one fits into the center of one link of the chain, the other fits into the center of the next link. With the chain properly in place, the pin is held in the center of the tool, so that the tip of the movable screw can press on the end of the pin. The end of the screw is slightly narrower than the pin, so that it can press the pin through the link. Often the end of the screw is a removable piece which can be replaced when worn. | ||
| This tool is required for removal and installation of the chain on a bicycle with ] gears, for maintenance or replacement. Bicycles with fixed gears front and rear, for instance the widely used coaster and three speed bikes, do not require this as they have a ] on the chain which holds the pin in place with an easily removable ]; this protrudes, however, and would interfere with the smooth operation of a derailleur system. This tool is used, however, should it be necessary to lengthen or shorten '''any''' type of chain. | |||
| ==Variations and alternatives== | |||
| ⚫ | |||
| ⚫ | Most chain tools are designed for chains where the links have flat plates. For chains with complicated shaped plates designed to facilitate smooth shifting, specific chain tools are available which are identical in design and operation, but have the ears protruding into the chain shaped in cross section to fit the links of the particular chain in question precisely, so as to hold the pin in the all-important vertical alignment with the screw of the tool. | ||
| Some chain tools are better at removing pins than they are at inserting them. Once completely removed, chain pins are often very difficult to insert with a tool unless it has been specifically designed to do so. Users may overcome this limitation of some tools by never completely removing a pin that they intend to replace. They push the pin so that the chain can be broken, to shorten it for example, but so that it is firmly retained in the farthest plate. This way, even simple chain tools can press the pin back into place. | |||
| In use, the chain is first placed into the lower position of the tool and the screw is turned in, pressing the pin through the top plate of the outer link and '''almost''' all the way through the center of the roller on the inner link, leaving just enough pin protruding that the inner link can be snapped free with a bit of pressure. This leaves the pin still aligned firmly vertical by the bottom plate; the pin should '''never''' be totally pushed through the bottom plate because it is then no longer fixed in the vertical axis and becomes almost impossible to re-insert. Even if the pin is merely pressed flush with the bottom plate it becomes more difficult to work with, as the chain now has to be held in alignment during reassembly, in contrast to leaving just enough of the pin protruding into the inner link to allow it to be snapped together by hand. | |||
| While a chain tool is required to shorten simple chains on a bicycle, and as described above, can often be used to reconnect them, there are fast-release chain links that allow repeated making and breaking of a chain. They are connected by hand pressure but often need a pair of needle-nosed pliers for removal. These links invariably replace a pair of ''outside'' plates on a chain, so joining two sets of ''inside'' plates. Bicycles with a single front chainring and rear sprocket (for example bicycles with hub gears or coaster brake hubs) may have a ] on the chain which holds the pin in place with an easily removable ]. Some master links are bevelled on top, and can interfere with the smooth operation of a ] system. Some derailleur suppliers have produced a chain with a fast-release link, made with straight plates to suit their derailleur products. | |||
| To reassemble, the chain is placed in position on the bicycle and the inner link snapped over the pin as described; the screw on the tool is now backed almost all the way out, and the chain is once more placed on the '''lower''' position of the tool, but this time with the pin protruding '''upwards''', towards the screw. Now the screw is turned in again, this time pressing the pin inwards through the roller and back into the other outer plate, leaving the chain assembled as it was in the first place. Examination of the relative amount of protrusion of the pin on either side of the outer links of the chain determines when to stop. | |||
| A chain tool is usually needed to shorten a chain, even when a fast-release link is being used, unless the combined number of links plus the connection link just happens to be the length required. Consider the following example. | |||
| Now, the upper position of the tool, with the chain held next to the screw, comes into play. The previous reassembly procedure usually leaves the outer plates of that link of the chain pressed tightly against the roller of the inner plates; this results in a "stiff link" which will tend to skip when shifting. To relieve this condition, the screw is backed almost all the way out once again, and the link of chain with the just-inserted pin is moved to the upper position of the tool. The screw is now advanced again, but only slightly, to press the pin forward just a tiny amount. Since the lower outer plate is not supported in this position of the chain on the tool, the pin is '''not''' pressed through the lower plate but only through the upper plate. Instead, the lower plate moves with the pin, relative to the upper plate, creating a larger separation; a very small movement is enough to release the pressure of the outer plates against the inner plates, freeing the "stiff link". This procedure can be used to free any "stiff links" which occur spontaneously, as well. | |||
| Assume that an old derailleur chain is to be replaced with a new chain containing a ''suitable'' fast release link, supplied with it. The old chain is broken with a chain tool to remove it, and counting the links it is noted that there were 112 in total. The new chain should have the same length, but counting its links concludes that including the fast-release link there are 116 of them. (The chain link count on a new chain will not necessarily agree with the number given on its packaging.) A chain of this type is provided with ''inner plates'' at both ends for this purpose. Bearing in mind that the chain must end up with two sets of ''inner plate ends'' after the shortening, then the chain tool can be used to completely remove four links. The fast-release link plates are installed by hand as if they were a set of ''outer plates'', and can be fixed in place by hand pressure alone. There are variations of the method in use, but in each case a chain tool will usually be needed. | |||
| ⚫ | |||
| ==Gallery== | |||
| <gallery> | |||
| File:Disassembling a bicycle chain with a chain tool.JPG|Disassembling a bicycle chain with a chain tool | |||
| File:Assembling a bicycle chain with a chain tool.JPG|Assembling a bicycle chain with a chain tool | |||
| File:Releaving tension between outer plates of a bicycle chain with a chain tool.JPG|Relieving tension between outer plates of a bicycle chain with a chain tool | |||
| </gallery> | |||
| ==References== | |||
| <references/> | |||
| {{Bicycle tools}} | |||
| ] | ] | ||
| ] | |||
Latest revision as of 19:45, 16 September 2024
Tool for disassembling and assembling bicycle chain | This article does not cite any sources. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: "Chain tool" – news · newspapers · books · scholar · JSTOR (December 2011) (Learn how and when to remove this message) |
| Classification | Bicycle tools |
|---|
A chain tool is a small mechanical device used to "break" a bicycle chain in such a way that it can be mended with the same tool. A bicycle chain has links and plates that are pinned together; these pins can be pushed out with the chain tool. Because the pins are pushed out gradually with a screw, they can be partially removed or fully removed, depending upon the intention of the user.
The chain tool has two positions where a chain can be inserted perpendicular to the tool, one close to the movable screw portion, and one lower down just above the fixed end. In each position, there are a pair of protruding tabs; one fits into the center of one link of the chain, the other fits into the center of the next link. With the chain properly in place, the pin is held in the center of the tool, so that the tip of the movable screw can press on the end of the pin. The end of the screw is slightly narrower than the pin, so that it can press the pin through the link. Often the end of the screw is a removable piece which can be replaced when worn.
Variations and alternatives
Most chain tools are designed for chains where the links have flat plates. For chains with complicated shaped plates designed to facilitate smooth shifting, specific chain tools are available which are identical in design and operation, but have the ears protruding into the chain shaped in cross section to fit the links of the particular chain in question precisely, so as to hold the pin in the all-important vertical alignment with the screw of the tool.
Some chain tools are better at removing pins than they are at inserting them. Once completely removed, chain pins are often very difficult to insert with a tool unless it has been specifically designed to do so. Users may overcome this limitation of some tools by never completely removing a pin that they intend to replace. They push the pin so that the chain can be broken, to shorten it for example, but so that it is firmly retained in the farthest plate. This way, even simple chain tools can press the pin back into place.
While a chain tool is required to shorten simple chains on a bicycle, and as described above, can often be used to reconnect them, there are fast-release chain links that allow repeated making and breaking of a chain. They are connected by hand pressure but often need a pair of needle-nosed pliers for removal. These links invariably replace a pair of outside plates on a chain, so joining two sets of inside plates. Bicycles with a single front chainring and rear sprocket (for example bicycles with hub gears or coaster brake hubs) may have a master link on the chain which holds the pin in place with an easily removable c-clip. Some master links are bevelled on top, and can interfere with the smooth operation of a derailleur system. Some derailleur suppliers have produced a chain with a fast-release link, made with straight plates to suit their derailleur products.
A chain tool is usually needed to shorten a chain, even when a fast-release link is being used, unless the combined number of links plus the connection link just happens to be the length required. Consider the following example.
Assume that an old derailleur chain is to be replaced with a new chain containing a suitable fast release link, supplied with it. The old chain is broken with a chain tool to remove it, and counting the links it is noted that there were 112 in total. The new chain should have the same length, but counting its links concludes that including the fast-release link there are 116 of them. (The chain link count on a new chain will not necessarily agree with the number given on its packaging.) A chain of this type is provided with inner plates at both ends for this purpose. Bearing in mind that the chain must end up with two sets of inner plate ends after the shortening, then the chain tool can be used to completely remove four links. The fast-release link plates are installed by hand as if they were a set of outer plates, and can be fixed in place by hand pressure alone. There are variations of the method in use, but in each case a chain tool will usually be needed.
Gallery
-
Disassembling a bicycle chain with a chain tool
-
Assembling a bicycle chain with a chain tool
-
Relieving tension between outer plates of a bicycle chain with a chain tool
References
| Bicycle tools | ||
|---|---|---|
| Hub, wheel, and tire |  | |
| Headset | ||
| Drivetrain and bottom bracket | ||