Bicycle crank puller

Connecting rods

Cranks are some of the most heavily stressed bike parts. On domestic road bicycles, they are made of steel, and on imported and sports bicycles. from aluminum alloys. To reduce weight and maintain strength, manufacturers go for different tricks. make them hollow, having intricate cross-sections.

Sometimes (more often on inexpensive bicycles) the block of front sprockets is made in the form of a non-separable structure, combined with the right connecting rod, and then when replacing the sprockets, both connecting rods have to be replaced. On mid to high end bikes, chainrings can usually be detached from the right crank arm, meaning they can be changed independently as the teeth wear out.

The need to replace the connecting rods also arises when they are broken or damaged. You have to remove the connecting rods (one or both) in order to get to the carriage (to adjust or replace it).

Usually new connecting rods are purchased together with chainrings.

When buying new connecting rods, it must be borne in mind that there are several types of carriages, differing in the type of axle. Choose connecting rods that are compatible with your existing bottom bracket. In addition, the connecting rods are available in different lengths (from 165 to 180 mm). Crank rods that are too long on a small frame can be inconvenient when riding on uneven terrain, and too short will require extra pedaling effort.

Bicycle crank puller

Connecting rod puller (system puller). a tool that allows you to remove the system from the non-integrated carriage shaft. Usually combines two functions: a hexagon for disassembling pedals-treadmills and the actual puller.

The connecting rods are held on the carriage shaft by a bolt for an internal hexagon 8 mm But just unscrewing the bolt is not enough, since the connecting rod sits with an interference fit on the carriage shaft and sometimes sticks, so a special puller is required. It is a screw with a two-piece head (socket wrench and open-end wrench), onto which a special shaped nut with an internal and external thread is screwed. Often an adapter is included with the puller for use with slotted standard carriages.

Installing connecting rods

The key is cleaning all joint surfaces and generously coating them with grease. Firstly, this will make it easier and smoother to install the connecting rod, secondly, it will greatly facilitate its subsequent removal, and thirdly, it will eliminate one of the most common sources of mysterious crunches and creaks somewhere in the carriage area. The connecting rod must be deeply seated on the shaft to prevent backlash, otherwise the seat will quickly fail. This is achieved by tightening the fastening bolts with a torque of 50-70 Nm, that is, with a very high force.

Types of connecting rods and carriages

This is the OCTALINK standard. On carriages of this type, the axis has a circular cross-section, and there are 8 protrusions at the ends of the axis. Bicycles of this type are equipped with bicycles of the upper and middle price range. This type of crank is used on expensive mountain and road bikes. (in particular, for SHIMANO. on DEORE LX / XT and XTR equipment, although recently it is increasingly used in components of the middle price category) The connecting rods are attracted by a special hollow bolt, under an internal hexagon by 10, and are protected from outside from dirt by anthers. The boot is simply screwed into the connecting rod. The carriage axis is hollow, and therefore traditional pullers do not work. they simply have nothing to rest on. It is necessary to use a special puller
This is a connecting rod of traditional design. This type of crank is used on mid-range bicycles. (for SHIMANO. on DEORE, ALIVIO, ACERA equipment). Although, OCTALINK has begun to be used on new equipment of these classes. The connecting rods are attracted by a screw, which is screwed into the axle. The screw has an internal hexagon socket of 8 mm. A plastic boot is put on the screw
This kind of connecting rods is also common. It differs from the previous design only in that the screw attracting the connecting rod is located under the plug. the boot. The connecting rods are attracted by a bolt that is screwed into the axle. The bolt can be unscrewed with a spanner wrench 14. The end of the carriage axis is closed with a plastic boot. In this photo, the boot is removed.
This type of crank is often used on inexpensive bicycles. Here, the carriage axis also has square sections at the ends. But here the connecting rods are attracted not by the screw, but by the nut. The nut is usually located under the boot.

There are other types of connecting rods. For example, on the new SHIMANO equipment (in particular, the XTR2003 and SAINT groups), the carriage is made in the form of a monoblock, when the right connecting rod is structurally combined with the carriage axis. To service such a carriage and connecting rods, a special tool is required.

Removing the connecting rods from the bike

In addition to the puller, an 8 mm hexagon is required. If the connecting rods (especially aluminum) have not been disassembled for a long time, you will need to fill the connection with machine oil, WD40 or some kind of liquid wrench so as not to rip the threads on the connecting rods. Before screwing in the connecting rod puller, make sure that the diameter of the puller pin, which will press on the square axle with the connecting rod fixed, is less than the size of the square hole. It so happens that a movable head is put on the finger of the connecting rod puller, the diameter of which is larger than the square hole of the axle. The consequences are dire if you do not stop in time. The puller rests against the connecting rod itself and begins to squeeze out not the connecting rod, pushing the axle forward, but itself, brutally cutting off the thread. The advice would be redundant if such cases did not occur. Having unscrewed the bolt, screw the puller into the connecting rod until it stops. The thread in the socket must be cleaned before this, and the screw of the puller must not protrude into the connecting rod (otherwise the puller will not be screwed in as deeply as it should). Then we tighten the puller bolt, squeezing the connecting rod off the shaft. It can take a lot of effort. be careful! If you overdo it, the thread inside the connecting rod will be torn off and you will have to change it (not to mention the problems of further removal), so you should not save time on soaking in oil.

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Bicycle cranks

We discussed what shifters and stems are. Today we will talk about connecting rods for bicycles and how to change them, what kind of pullers for connecting rods are and how to remove connecting rods from a bicycle.

The central thread for the puller on the connecting rod is damaged

This is a very frustrating situation, which essentially cancels out the ability to remove the crank arms easily and puts you in front of the question of how to remove crank arms without a puller.

You will need to swing the connecting rod yourself (with sharp movements, pre-fill the WD-40 slot) or knock them down with a hammer through a wooden block. The impact should be of a shock nature. It is important not to damage the frame or carriage. The connecting rod seat is gently pounded around the perimeter from different sides in the direction from the frame so that the connecting rod comes off.

If, after driving through the block, the connecting rod does not go, then you need to use a pry bar or chisel. It is inserted into the space between the bottom bracket and the crank arm and is used as a lever or straight stick to strike.

The impact depends on whether you will continue to use the connecting rods or replace them with new ones.

Often the option helps out to ride a couple of kilometers without a fixing bolt, until the connecting rod itself swings.

Sometimes cranks with a square mount made of soft aluminum are pressed so hard onto a square spline that an effect comparable to welding is obtained. In this case, there are practically no options to remove the connecting rod without damage. You can drill the base of the slot or make a cut with a hacksaw.

The option of heating the connecting rod with a gas burner is also practiced. But this is not the best option, because in this case, you can damage the aluminum frame or burn out the plastic inserts from the carriage. If there are no inserts, the oil inside the carriage will deteriorate. However, in rare cases, this technique is very helpful. In order to warm up the connecting rod, you need to anneal the attachment point of the slot with a gas torch or blowtorch. Then, preferably still hot connecting rod, knock down with a hammer.

Bicycle crank puller

There is also a way to make an impromptu puller. For example, make a hole in the connecting rod and fastening some bolt in it, try to push it against the adjacent connecting rod. Then, similarly to a standard puller, squeeze the connecting rod.

Why remove cranks from a bike

Sometimes it is necessary to remove the bicycle cranks in order to access the bottom bracket maintenance or to clear the dirt.

The connecting rods themselves can break. At first glance, this seems like an incredible development of events, but the connecting rods are susceptible to bending, damage to the spline, the connecting rods can break at any point or, which is the most common ailment, damage the thread for fastening the pedal.

bicycle, crank, puller

The thread in the crank arm for the pedal is a separate sad topic. Often the user overtights this thread, or vice versa, does not always control the tightening and tightens the loose mount. This will damage the threads. It would be possible to cut a thread of a larger diameter, but then standard pedals will not fit into the hole formed. In addition, the thread can be damaged due to the fact that the repairer began to screw the pedal at a slight angle and cut off the edges of the thread, or, better to say, ditched the thread on his own. In all these cases, the connecting rods will need to be dismantled and / or replaced with new ones. You can try to repair the connecting rods.

The connecting rods will also need to be removed from the bike if you need to change the stars (or one of the stars). Indeed, on modern connecting rods, the star is attached not with a welding machine or riveting, but with the help of so-called bonks. The sprocket is a consumable that breaks down and wears out much faster than the connecting rods themselves.

Most of the problems arise with aluminum connecting rods. If the quality of their workmanship is low, then they are actively broken and removed with great difficulty. It’s all about low-quality aluminum used on cheap products.

When is it necessary to dismantle the connecting rod

The connecting rod does not imply any maintenance and special care. Its replacement is carried out only in the case that we described above and in case of mechanical damage. The need for dismantling arises when we need to get to the carriage or completely disassemble it for lubrication, flushing or adjustments.

Also, sometimes after the rain, an unpleasant creak occurs, which is caused by the ingress of sand into the connecting rod-shaft interface. In this case, you have to disassemble it and clean the seat.

It’s just that the connecting rod will not be removed and for this you need to apply either a certain manual dexterity or a special puller. We will tell you about these methods in detail.

How to remove cranks from a bike

Ideally, when we use quality equipment and have a crank puller for a bicycle, there should be no difficulties. The whole structure in this case works in such a way that it helps us to carry out the actions necessary for maintenance.

Before removing the connecting rod, you need to unscrew the fixing bolt. hexagon or standard nut / bolt. This must be done very carefully so as not to overwhelm the edges on the hexagon / nut. Further, it would seem, the connecting rod should come off, but this does not happen. An interference fit is used. The connecting rod cannot be removed with your hands and you will need to squeeze the connecting rods.

If we consider modern connecting rods, then a special puller-squeeze is screwed into the central hole of the connecting rod, which rests on the carriage and pulls (when the puller nut is twisted) the connecting rod from its seating point. This is how the connecting rods for the square and the connecting rods for the slot are removed. The puller must be screwed in absolutely evenly and over the entire length of the thread. Otherwise, the puller will pull itself out along with the thread, and the connecting rod will remain in place.

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On some systems, the puller has nothing to rest on the carriage. In this case, you need to either leave the fixing screw in place, pressing the connecting rods and rest against it, or put a coin. A longitudinal axle (bolt or wheel axle) can be used to push against an adjacent retaining screw. It is important to remember that you can accidentally damage the thread of the connecting rod fixing bolt on the carriage or press your stop into the carriage thread, and this will require replacing the carriage, which is sometimes even more laborious and expensive.

With connecting rods on a key, the situation is a little more complicated. There, you first need to knock out the key, and then swing the connecting rods (for example, with light but sharp blows of a hammer through a wooden block). There is also a recommendation to ride around the yard without a dowel until the connecting rod swings by itself, although this option is not always effective. The key is knocked out with a hammer. Pullers are not provided for such connecting rods. It is knocked down with a hammer.

In practice, situations are usually different and very different from the desired ideal. The connecting rods often burn or break off the fastening nuts, and the connecting rods themselves do not always get off the landing point on the carriage very easily. What are the most common problems?

Installing the connecting rod

By the last stage of the repair, all parts should be cleaned and generously coated with grease. This will make it easier and faster to put the crank back on the bike. In the future, it will be much easier to remove the part, and during the ride there will be no unnecessary squeaks and crunches.

The connecting rod is deeply seated on the shaft so that no backlash occurs during movement, otherwise the seat will loosen and be broken. Fixation is achieved by tightening the mounting bolt by 50-70 Nm with significant effort (taking into account the length of the connecting rods). It is recommended to inspect the integrity of the connection before installation. The process is carried out as follows:

  • Put the chain on the carriage (when installing the right element), then the connecting rod on the axle, tighten the tightening fastener.
  • When putting on a different connecting rod, it is important not to confuse its position.
  • Tighten the bolts tightly, otherwise it is fraught with breakages.
  • Put on the plugs from the dirt, the chain on the sprocket.

The connecting rod is an important part that carries a significant portion of the load. It is simple in its structure, therefore it can be dismantled without problems, it can be replaced in the event of a breakdown. When repairing, it is worth using a puller, study the instructions on how to remove the connecting rod from the bike, especially if there is no experience of the corresponding work.

How to remove connecting rods from a bike without a puller? Helpful hints

Bicycle transmission tends to wear out even with proper and timely care. Most people, of course, do not have special bicycle tools, and if you suddenly felt an urgent need to replace its components, then, most likely, you wondered how to remove the connecting rods from a bicycle without a puller and is it possible to do it yourself? To deal with this, it is worth learning more about the connecting rods themselves and the types of carriages.

Crank Removal and Installation. Three Piece Crankset (Square Spindle, ISIS, Octalink)

The slot on the fixing bolt is damaged or the edges of the nut are cut off

This is a rather significant problem, which, probably, should have been mentioned from the very beginning. If you accidentally ruin the spline on the bolt that secures the connecting rod in its place, you will have many joyful adventures.

When you need to remove the connecting rod from the bike bottom bracket, the first thing to do is unscrew the fixing bolts. When the connecting rods are working, they always have some micro-play (especially the square connecting rods). This micromovement constantly tightens the connecting rod bolt. The right connecting rod tightens the bolt, and the left one unwinds. Therefore, the sprocket connecting rod is much more difficult to unscrew. If, when unscrewing, you find that the bolt does not go, then there is no need to rush.

The connecting rods are fixed either with a hex bolt, or a nut, or the most common bolt. The greatest risk is to rip off the edges of the hex bolt. Hasty action and the use of a blocked hex increase this risk. Therefore, always carefully and carefully secure any key before applying force. If the screw does not give up, use WD-40 and similar. Apply the enlarged lever and smoothly, without jerking, unscrew the bolt millimeter by millimeter.

The screw can be warmed up a little (again, very carefully) or the torx can be driven into it on a large size.

If you are lucky enough to rip the spline, then you will have to drill out the bolt.

Puller application

A special device that is designed to dismantle hard-to-remove parts is called a puller. This is a no brainer. In our case, to remove the connecting rod from the bicycle carriage shaft. It looks like this.

This type of connecting rod puller provides the ability to remove the pedal as well.

The connecting rod is held on to the shaft by a heavy-duty 8mm head bolt. It is not difficult to unscrew the bolt. But the difficulty is that the connecting rod sits on the shaft with a slight interference fit and has a tapered fit. Very often, in wet weather, water and dirt penetrate into the interface between the connecting rod and the shaft. Then it sticks to the shaft and it is almost impossible to remove the connecting rod. But in our toolbox, of course, there is a puller for connecting rods, which is a complex turning part. a screw with a two-level head for an open-end wrench and a socket. A cunning nut with external and internal threads is screwed onto the screw. It takes a long time to explain, but in the photo everything is very clear.

Connecting rod puller

In fact, in the bike system, more attention is required to the carriage and sprockets, since the cranks do not need to be lubricated, they do not need to be adjusted. But it is they, like the titans, who bear the entire burden on themselves. Therefore, it is simply impossible to ignore them. So how to remove the connecting rods, why do it and is it possible to do without a special tool. puller? Let’s figure it out.

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Why are connecting rods needed

In general, it is quite problematic to break this part. over, most often on modern bicycle models, durable carbon fiber parts are installed. If you have a bike from a domestic manufacturer, then the connecting rods (aka drawbars) can be made of steel. In any case, they are not only durable but also reliable. protect sprockets and carriage from damage and dirt. This is their main purpose.

As for the types, such parts are conventionally divided into one-piece, two-piece and three-piece:

TypeCharacteristics
One-piece One-piece mechanism used mainly on children’s and retro bicycles. Such parts are heavy, but in addition to it, reliability and strength are attached. Does not require special care.
Two-piece A more sophisticated bicycle system, which is a collapsible mechanism, where the left crank is separated from the rest of the bike. Until recently, this type was also considered outdated and was installed only on bicycles in the budget price category. However, Shimano has been reviving the two-piece drawbar in the eyes of consumers for several years now.
Three-part Three-piece, respectively, consist of three parts: the axis, the left and right of its counterpart with a set of stars. This species is most common in the modern velomir.

Connecting rod remover. how to remove the system

The crank puller is a tool with two wrenches at the ends. nesting and carob. It’s no secret that it is almost impossible to remove parts without this invention, so you should definitely get one. Here’s how to use the tool. we will tell.

  • Before picking up a serious tool, it makes sense to use the WD40. This is a special fluid that removes all blockages on the connecting rods. Simply by wiping the part with it, you will greatly facilitate your task;
  • Now, with a light heart, you can unscrew the bolt at the connecting rod and shaft attachment point. Make sure that the connecting rod puller is slightly smaller than the square of the connecting rod itself. Otherwise, the risk of simply ripping off the bolt increases significantly;
  • After we managed to remove the bicycle bolt, which serves as a plug, we turn the tool over with another key towards us and screw it under the thread in the connecting rod to the limit;
  • Now, carefully, trying not to overdo it, we try to squeeze the connecting rod out of the carriage. Done!

Drastic measures

If you don’t have a crank puller yet, but remove the system from your bike as it should, there are ways to do it without a tool. Here is some of them.

Sledgehammer: for impulsive individuals. We cover the drawbar with a rag and hit it with all our strength with something very heavy. The goal has been achieved. Typically, this method has one side effect. you can never put the system back together again.

Trust in fate: for extreme lovers. We lubricate the bolt with cleaning fluid (you can use the same WD40), lower it a little with improvised means and go to the track. The probability that the part will unscrew itself is very high.

Iron version: the most reliable. Without carrying out any preliminary work, we go on a trip to the nearest workshop, where, for a fee, specialists will carry out all the necessary procedures for the bike and help to remove the system from the bike.

Thus, we can conclude that it is not at all necessary to have a puller for connecting rods, but it can be great to save you from unnecessary financial expenses.

Connecting rod puller

Connecting rod puller (system puller). a tool that allows you to remove the system from the non-integrated carriage shaft. Usually combines two functions: a hexagon for disassembling pedals-treadmills and the actual puller.

The connecting rods are held on the carriage shaft by an 8 mm Allen bolt [1] But it is not enough to unscrew the bolt, as the connecting rod sits with an interference fit on the carriage shaft and sometimes sticks, so a special puller is required. It is a screw with a two-piece head (socket wrench and open-end wrench), onto which a special shaped nut with an internal and external thread is screwed. Often an adapter is included with the puller for use with slotted standard carriages.

[edit] Application

[edit] Removing the connecting rods

In addition to the puller, an 8 mm hexagon is required. If the connecting rods (especially aluminum) have not been disassembled for a long time, you will need to fill the connection with machine oil, WD40 or some kind of liquid wrench so as not to rip the threads on the connecting rods.

Before screwing in the connecting rod puller, it is necessary to make sure that the diameter of the “pin” of the puller, which will press on the square axle with the connecting rod fixed, is less than the size of the square hole. It so happens that a movable head is put on the finger of the connecting rod puller, the diameter of which is larger than the square hole of the axle. The consequences are dire if you do not stop in time. The stripper rests against the connecting rod itself and begins to squeeze out not the connecting rod, pushing the axle forward, but itself, “brutally” cutting off the thread. The advice would be redundant if such cases did not occur.

Having unscrewed the bolt, screw the puller into the connecting rod until it stops. The thread in the socket must be cleaned before this, and the screw of the puller must not protrude into the connecting rod (otherwise the puller will not be screwed in as deeply as it should). Then we tighten the puller bolt, squeezing the connecting rod off the shaft. It can take a lot of effort. be careful! If you overdo it, the thread inside the connecting rod will be torn off and you will have to change it (not to mention the problems of further removal), so you should not save time on soaking in oil.

[edit] Installing connecting rods

Key moment. this is cleaning all surfaces of the connection and generously coating them with a thick lubricant. Firstly, this will make it easier and smoother to install the connecting rod, secondly, it will greatly facilitate its subsequent removal, and thirdly, it will eliminate one of the most common sources of mysterious crunches and creaks somewhere in the carriage area.

The connecting rod must be deeply seated on the shaft to prevent backlash, otherwise the seat will quickly fail. This is achieved by tightening the fastening bolts with a torque of 50-70 Nm, that is, with a very high force.