How an asterisk works on a bicycle

Why not use small cassette stars.

In this section, it will be shown that stars 11, 12, 13 are fundamentally worse than the others. Therefore, if the use of a large chainring in the front avoids working on the 11,12,13 stars at the rear, it gives a noticeable result.

Chain drives are reduced to the rotation of polygons, the more teeth, the closer the polygon is to the circle. In fig. 1 for clarity, a polygon is shown in red, which forms a chain on a sprocket of 11 teeth. The chain pivots form the vertices of the polygon. The moment is recorded when the working link of the chain (the link for which the chain rotates the cassette) is parallel to the chain. When pivoting half a tooth, when the pivot is at the yellow point, the chain will lift. When turning another half of the tooth, it drops again, the situation will again be as in the photo. Thus, during operation, the chain beats. This is a feature of rotating polygons, nothing can be done about it. The larger the star (in terms of the number of teeth), the smaller the chain runout amplitude. By the way, in engineering calculations of the chain, it is not recommended to take the number of teeth less than 13. In bicycles, the situation is worse, since the teeth are filed so that the chain can move from star to star. To do this, the chain pivot only needs to be raised by 0.4 mm. And the bottom cut in the chainring is made about 0.4mm deeper than the chain polygon can drop. In general, the runout amplitude of the chain should be compared with the maximum possible movement of the chain roller before it leaves the tooth. If the runout is greater, then when the transmission is operating, the chain may not cling well to the teeth. Here is a graph of the beating amplitude with such a border marked.

It can be seen that the engagement on the cassette stars 11, 12, 13T is not reliable. It is also better not to use 14T. If the teeth are not filed (bicycles with one gear), then 11T and even less can be used normally. But this is not the case with bicycles at speeds. Therefore, if a large sprocket in front makes it possible, all other things being equal, to shift at least one sprocket of the cassette in the range of 11-14T, this will give a noticeable advantage in the softness of the engagement of the chain joints with the teeth of the sprocket.

Maybe very big stars on the pedals are not needed?

If you ask the Internet why this is so, the first answer is that very large stars in the system are not needed, since the need manifests itself only at such calculated maximum speeds to which a particular bike cannot be accelerated. For example, at a cadence (number of revolutions per minute) of 80, on a bike with a wheel diameter of 27.5 inches, a maximum gear of 42/11 gives an estimated speed of 41 km / h. and 38/11. 37 km / h, despite the fact that a good cruising speed for a bike is 30 km / h. And in the lower gears, the range is enough. That is, if you drive 28-29 km / h with a cadence of 80, it does not matter that in gear 42/16 or 38/14. Therefore, a large star 42T is not needed at all, 38T or even less is quite enough, especially if it is only one

In my experience, I cannot agree with this. On my particular bike, even in the forest, I use 42/11 gear very often, on descents. In general, there are other cases besides reaching the hypothetical maximum speed on ideal surface. But most importantly, I can’t agree at all that it’s all the same on which star to maintain speed. It is better to twist on a big star in front. That is, if you need, for example, to go up a hill at a speed of 14-15 km / h, then this can be done on any of the three front stars, corresponding to ratios 42/24, 32/18, 22/12. And here, in practice, it is very noticeable that all these programs are different. And the most efficient operation of the chain drive (according to the sensations) is just on the big star, 42/24. In this gear, the elasticity is much higher. compensation for small changes in speed depending on external conditions, it is generally smoother to turn and easier to accelerate if necessary. It is clear that most of these sensations can be just in the head. Digging the Internet showed that not only in my head. Popular cycling wisdom is full of sayings like big ring is king, you can go very fast on a small star, but if you put it on a big one and break in, you will go faster, etc. Not a single saying that all stars are the same did not catch my eye

In general, you need to figure it out. There have been attempts like this on the Internet, I saw a joyful discussion with reference to a 1998 scientific work showing that on large stars, the efficiency of a bicycle transmission is 0.6% more. And this is the only confirmation of numerous observations from practice. I don’t think I would have felt that 0.6%, so the research shows that if you dig, you’re in the wrong place.

Then there will be a lot of boring numbers and graphs, but in general there is a positive result, you can even feel it in numbers

Big stars and breaking into a hill.

Engineering calculations of the chain give the dependence of the tension force of the working section of the chain on the diameter of the star. The larger the diameter (i.e. the number of teeth), the less tension. Since there is no particular difference in the choice of stars from the 1998 article mentioned above, it means that the tension of the working section of the chain does not lead to changes in efficiency with uniform pedaling. But a person is not a motor, a person does not pedal evenly. over, it feels like an advantage in the big sprocket in front precisely when pedaling uphill powerfully. This is even more noticeable when breaking into an MTB junkie, when there is no need to talk about some kind of steady pedaling. That is, you need to understand how the tension of the working section of the chain is associated with accelerations. a change in the speed of rotation. The closest is the moment of starting, when there is almost no speed, but there is acceleration. That is, we apply force to the pedals and watch when the bike moves. Next, we compare the resulting effort in close gears, but obtained with a different ratio of stars. I did not find the corresponding engineering calculations of the forces when starting the chain transmission. Fortunately, such an experiment is easier to carry out than delving into theory.

The figure shows a measurement of the force applied to the pedal to rotate the braked rear wheel. Chain on the star of the 50T system. To start the wheel, you need to apply a force of 3.5 kg when the chain is on the star of the 28T cassette and, accordingly, 9 kg when the chain is on the star of the 11T cassette. A series of three measurements was carried out. The data is better represented as the dependence of the pulling force on the transfer.

Thus, for the 50T star, a linear dependence of the breakaway force on the transmission (the ratio of the front and rear stars) was obtained. Now you need to compare these straight lines for all three chainrings and see the difference in breakaway force in the same gears. If it is easier to break in on a large star, then the 50T straight line will be below 39T, and the 30T straight line should be the highest.

Alas, the miracle did not happen. These three stars add up to a linear, downright ideal gearbox. It does not matter at what ratio of stars to swing the bike, or the same thing. to break into the jumper on an ultra-low cadence. Thus, when power pedaling, a large sprocket has no advantage in transferring power to the wheel.

Big stars on the pedals, bigger is better

Many try to spin the systems on the big stars. I also came to the rule: If you can spin a big star, then you need to. But how reasonable is this? I must say that in the development of bicycle transmission, there is a tendency towards a decrease in the number of stars on the pedals. A few years ago, the norm was three, now two, sometimes one. The total range of large stars is also decreasing. For example, a budget bike used to have a 42/32 / 22T system (stars in front) with an 11-32T cassette (rear sprockets), now on a bike of the same class, a 38 / 24T system with an 11-36T cassette. The increase in the small sprocket in front is fully compensated by the increase in the large sprocket in the cassette (the minimum gear was 22/32 = 0.69, and it became even more powerful 24/36 = 0.67). But the reduction of a large sprocket in front cannot be compensated for by the sprockets in the cassette, since there are no sprockets with less than 11 teeth in the cassettes.

Large sprockets and chain drive jerks.

It so happened that just after finishing the measurements, I put a new 53T sprocket instead of 50T on the road bike system, because in the last brevet I used the smallest sprockets on the cassette too often. And we went for a ride on our standard route of this season at 83 km. I did not expect miracles, but I listened to the sensations. It’s still easier to pedal. But if it’s not about effort, then what? The pedaling is clearly smoother. over, on the middle stars in the cassette, i.e. regardless of the consideration of the chain beating in the first section of the note. The chain transmission, since it is built on rotating polygons, transmits rotation in jerks. Here we will deal with this in this section.

Let’s go back to Fig. 1. The chain is filmed at the point when the force with which the hinge pulls the sprocket tooth is not directed tangentially to the circle of rotation. Therefore, the force that untwists the sprocket is less than the force with which the chain pulls on the hinge. And at the yellow point, the chain coincides with the tangent to the circle, so the chain’s force is completely transferred to the rotation of the sprocket. This leads to jerks in the rotation of the sprocket and, consequently, the rotation of the wheel. This should feel like a smooth ride on the pedals. Leading stars have the same jerks.

Fig 6. Amplitude of jerks of transfer of forces on different stars

The amplitude of jerks on the 11T star is 4% of the force, on the 30T star. 0.5%. It is hardly possible to feel such a vibration of one tooth with your feet. Rather, the number of jerks will be felt, say, in one pedal rotation. That is, I turned the revolution, I got the number of jerks, both from the leading star and from the driven one. For simplicity, we assume that there is no inertia, therefore the sensitivity to jerks is maximum, that is, jerks are perceived as uneven movement of the bike. The first estimate immediately gives a good graph that matches the feel.

The transmission is smoother with larger chainrings. That is, where the gear can be selected with a different combination of stars, the move will be the most ragged on the small star in front. In other words, with one pedal rotation with the chain on the chainring of the 50T system, we can feel 50 small jerks from the leading sprocket and 50 stronger jerks from the driven sprocket with our feet. If the same ratio is chosen with a 39T front sprocket, then we get 39 jerks from the leading sprocket per pedal revolution, a little more than from 50T and 39 jerks from the rear sprocket, which is less than in the previous case, and the jerks from it will be much greater. The product of the number of jerks by their amplitude in the second case will be noticeably higher, for example, for a transfer of 2.5 by 30% (the Y value on the graph is 1.0 versus 0.75). How do these jerks work??

Consider the rotation by one tooth of the 11T sprocket and, for comparison, by the same angle of the 28T sprocket. Let’s start from the point of maximum transmission of the chain pulling force (yellow point in Fig. 1). The force of rotation is equal to the pulling force of the chain, the transmission multiplier = 1. Then this force decreases smoothly. When the working link of the chain on the sprocket becomes parallel to the mowing line of the chain (as shown), the pulling joint changes. The previous hinge breaks away from the sprocket, the next one begins to work. On the graph, this angle of rotation of the sprocket corresponds to a sharp kink in the change in the rotational force. After that, there is a smooth increase in the rotational force. I think the jerks are felt at this break. If we compare the graphs for the 11T and 28T stars, we can see that in addition to the larger jerk amplitude for the 11T star, this jerk is also sharper. If we introduce inertia into the system, as is the case on a real bicycle, then the breaks in the graph will be somewhat smoothed out. In this case, small kinks will go away altogether, but large ones will still remain, that is, the difference from the sharpness of the kinks will be even greater. Therefore, the degree of kink must also be introduced into consideration. All this is also well considered and the final dependence of jerks per pedal revolution on the selected gear is even more beautiful (even without taking into account inertia, that is, only bare geometry).

It can be seen that, for example, for transferring 2.5, the smoothness of the transfer of forces from the legs to the wheel with a large sprocket of 50 or 53T is two times better than at 39T, and 39T is almost two times better than 30T. over, there is really a noticeable difference between 53T and 50T on the middle sprockets of the cassette. It is 10-15%.

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The effect of jerks of efforts is most likely more noticeable at low speeds, at high speeds the inertia of all all rotating elements will begin to work much stronger, which should smooth out jerks. That is, just on power pedaling with low cadence.

Summing up the three sections, you need to formulate the following.

It is necessary to avoid, if possible, work on small sprockets (11-13T) of the cassette, especially at high speeds. The chain will thresh along the teeth until overshooting.

When starting off and at the beginning of acceleration, it does not matter at all how the gear ratio is chosen, on which stars. In this case, the preference for better acceleration on small stars in front or on large ones, exclusively in the head.

At low to medium speeds, it is better to choose a large sprocket in the front (and correspondingly large sprockets in the back). This affects the smoothness of pedaling. Here it is also necessary to note the often-mentioned chain skew, which supposedly needs to be avoided. In my experience and according to the measurements carried out, the skew of the chain does not affect anything, so if the transmission allows it, then, to the point of absurdity, it is better to twist on a large sprocket in front and on a large sprocket in the back. over, in the article Bicycle chain and liquid paraffin, he considered that a bicycle chain is fundamentally different from a classic one in that it adds flexibility to the skew by reducing the resource. There is really nothing strange about this, since flexibility to skew is fundamentally necessary in order for the chain to move from star to star when changing gears.

As the inertia of the rotating elements (for example, heavier wheels, or an increase in rotation speed) increases, the dependence on the choice of leading stars becomes less.

Vadim Nikitin

Gear ratio of leading and driven stars

The sprockets on high-speed bikes are located on the right crank arm (driving) and the rear wheel hub (driven). Through the chain, forces are transmitted from the front gears to the rear. Interestingly, the rear wheel, on the contrary, is the driving wheel, and the front wheel is driven.

Gear ratio is the difference between the size and the number of teeth on the stars. This parameter directly affects the travel speed and transmission power. A high gear ratio is provided by a large drive and small driven gears, a low gear ratio, on the contrary, by a small front sprocket and a large rear sprocket. Accordingly, the gears on the classic transmission in the first case are 3 x 8, and in the second 1 x 1.

The larger the chainring, the higher the speed. For example, there are 44 teeth on the front for the chain engagement, and on the back there are 11 teeth. For one revolution of the pedals, the rear gear will make 4 revolutions. If we take gear 22 to 11, then only 2 wheel revolutions will be made here per pedal rotation. At low gears, the opposite situation is observed: in front of the chain stands on a 22-tooth gear, and at the back on 32. The gear ratio is less than 1, that is, for 1 revolution of the pedals, the wheels do not have time to turn completely.

High gears are designed for fast travel on a flat road. On hills, in headwinds and in poor road conditions, lower gears are used. the speed of the bike is lower, but more power and less energy consumption. Medium star ratios such as 2 x 5 and 2 x 6 are often used.

Each star in the system has its own range on the cassette. He can float, that is, the same reverse gear refers to two stars of the system at once, but, in principle, the pattern is as follows:

What do we have for single speed bikes? There are only a couple of gears, a classic gear ratio of 2. Corresponds to average performance on high-speed models, intended for movement on asphalt, compacted soils, conventionally acceptable on short climbs.

You can increase the speed of a single speed bike yourself if you put a larger diameter sprocket in front. For frequent overcoming of slides, it will be more relevant to increase the size of the rear gear.

And finally, how the programs are numbered. In the system, the asterisks are arranged in descending order, on cassettes. in ascending order. The outermost gears are the highest gears, the inner ones are the lowest. The smaller chainring corresponds to the first gear, in the cassette to the last gear. According to the number of stars in front and behind, the gearing of the transmission is determined, for this we multiply the numbers:

  • 1 x 7 = 7 gears;
  • 3 x 7 = 21 gears;
  • 3 x 8 = 24 gears;
  • 3 x 9 = 27 gears.

Etc. Do you need so many speeds in practice? It all depends on the riding style and the area of ​​use of the bike. However, it is important to choose the correct sprockets. this way they and the chain will be subject to less wear and tear, and the trip will be more comfortable. And if the transmission allows you to select the gear with maximum accuracy, then this is how it should be done.

Types of fastening stars on a cassette

Let’s go back to the classic round cassettes. Unlike ratchets, they differ in the type of attachment to the drums. Bicycle cassettes are:

  • collapsible on a single drum with separators;
  • on a spider;
  • on blocks (several spiders);
  • Open-Glide;
  • X-Dome.

The first type of cassette is the simplest. all the stars are installed on a single spline drum. They are separated from each other by partitions. spacers. The disadvantage is the constant load on the drum. But the indisputable advantage is that they are easy to disassemble and change one asterisk. They are easy to clean, but the components are more likely to get dirty.

Spider. Lite version of the collapsible cassette. The load on the drum is not so big. here it does not come from each star, but only from the spline mount of the spider. These cassettes are lighter, less likely to get dirty.

The multi-spider design includes multiple pairs plus small stars individually attached to the drum. The model is very convenient because the new block is easy to pick up and, unlike the collapsible analogue, you don’t have to fiddle with spacers for a long time and lay out the entire cassette. The development of this thing belongs to the Japanese manufacturer of parts Shimano.

The Open Glide is a one-piece set that fits onto the largest gear. Unpretentious model: thanks to high-quality material, less wear and tear, long service life, low weight. True, cleaning a heavily soiled cassette is problematic.

The X-Dome system is represented by a similar design. Here, both the big and the small stars are in contact with the drum. A solid-milled block of 7-8 stars is mounted on them. Both Open-Glide and X-Dome are SRAM.

Oval stars, different from round

Oval Star. New Or Retro Splash? We can say both. Experiments with the shape of gears for a chain drive (namely, giving it a flattened shape) began in the nineteenth century. Then it was somehow forgotten, and in recent years it has returned and is actively introduced into the modern cycling life.

asterisk, works, bicycle

The eccentricity of the star is slightly greater than zero, so the shape is close to a circle, by analogy with the Earth’s orbit. The maximum constriction can be up to 30%. They are not popular in our time, the release is more aimed at racing models.

The ellipse rotating around the axis redistributes the loads in its own way and changes the efficiency of the transfer moment.

Consider what are the features of ellipsoidal gears:

  • jumps in the gear ratio of the stars;
  • more even distribution of loads. a decrease in them with the horizontal position of the connecting rods and an increase in the vertical one;
  • overclocking is pronounced;
  • additional loads on the carriage shaft.

In accordance with this, we will analyze the pros and cons of such stars in comparison with round ones:

Benefits disadvantages
The bike will roll uphill faster Faster rear cassette wear
Better low cadence pedaling in high gears Increased load on the carriage
Acceleration by additional pushing torque (system) Need to pedal more often in low gears
Even distribution of muscle stress, less fatigue on flat areas
Easier to ride MTBs with powerful cushioning

An elliptical drivetrain pays off when you have to pedal at low cadence. Compared to the round counterpart, it provides some advantage in accelerating the bike from a standstill. There is also a change in the gear ratio without switching.

  • front. horizontally, back. vertically;
  • in front. vertically, driven. horizontally;
  • only horizontal position;
  • only vertical position;
  • deviation: for example, the leading sprocket is strictly vertical, and the rear sprocket is at an angle from a straight line.

Thus, the oval system and cassette leave prints of fundamental differences on the bike: both in appearance and in ride quality.

Bicycle sprockets

Sprockets are transmission units for the implementation of a chain transfer of forces from the cyclist’s legs to the rear wheel. Bicycle sprockets play a paramount role. without them, it simply will not go. Single speed models are supplied with a pair of leading and driven stars. Bicycles with multi-speed transmissions are equipped with speed kits front (system) and rear. ratchet or cassette.

The number and size of the sprockets determine the bike’s flexibility in various road conditions. Thanks to the correct gear ratio, you can significantly reduce the energy consumption for the trip and move at a comfortable speed. The durability of parts depends on the quality of the material, the riding style and the quality of service. with proper care, even starter stars will ride longer than professional, but neglected ones.

How to clean and lubricate sprockets

Rubbing mechanisms require periodic lubrication and cleaning from dirt. This will improve ride quality and extend the life of the transmission. Chain guards are often included with classic single-speed models. It is recommended to leave it. It also protects the chainring from excess dirt.

Already after a few rides through forests, cross-country and off-road, the mountain bike is overgrown with mud. And if it is clearly visible on wheels and frame, then in mechanisms it is not always. Therefore, more often you need to inspect your two-wheeled horse and take action in time.

Cleaning the bike cassette: 1. Release the rim brake (remove the caliper on the disc brake), remove the rear wheel.

Inspect for dirt. If everything is very bad, you will have to remove and disassemble the cassette. For light dirt, can be cleaned directly on the wheel.

For cleaning it is better to use special narrow brushes. They allow you to crawl into the deep gaps between the gears and find a lot of interesting things there. And it is much more convenient than getting into the gaps with a rag.

You can clean the teeth with an old toothbrush or wipe off the abrasive with a soft cloth.

After that, wipe the surfaces with kerosene, allow to dry and apply grease to the teeth and pits. It is recommended to clean and lubricate the chain at the same time as the cassette. This is the only way to achieve the desired result.

003 What is Asterisk and what can you do with it

Cleaning the system is done by analogy. Everything is simpler here: you don’t need to remove the wheel, just a few stars. True, you need to work carefully so as not to damage or upset the switch.

Sprockets are the most important components of the transmission, without which movement is impossible in principle. Correct selection of gears, periodic cleaning and timely replacement of worn components will avoid unpleasant surprises on the road, and a high-speed bike will really be high-speed, and not only ride in one gear.

How to replace front sprockets on a bike?

Change chainrings on your bike with our step-by-step video tutorial. Replacing the sprockets on a road or mountain bike is a fairly straightforward task, but one that needs to be done urgently when the cogs wear out. You can swap the chainrings to change the gear ratio, lowering which will make it easier to climb slopes, and increasing it will speed up in flat races.

Before starting work, find out the exact landing diameter (PDD) of your leading star system before purchasing new ones. Typically PDZ 110 or 130 mm. or significantly reduced or traditional size. If the bike is equipped with a 50x34T system, then the PDR is almost certainly 110 mm. If it is 53x39T, then the PDZ will be 130 mm.

Of course, you can always measure the circumference of your system to be sure. There are exceptions, such as the “four feet” used in Shimano’s newest 11 speed hitch, for which sprockets of various sizes are available without worrying about the difference in PDL.

How to replace asterisks?

If your goal is not just to replace the outer sprocket. which can be easily done by removing the fasteners and threading it through the connecting rod. you will have to start by removing the drive sprockets. 2. Some high quality connecting rod systems allow you to remove the sprocket bolts with regular hexagons or special Torx wrenches, but if your sprockets have regular bolts, you need either a special puller wrench that can be placed in the slotted groove of the sprocket nut or another hexagon (often 1 mm larger than the front) to keep the nut from turning. Special key. a puller holds the sprocket nut immobile while unscrewing or tightening the bolt.

Lock the nut and unscrew the bolts counterclockwise. Remove them carefully, they will come in handy for installing new sprockets. You can now remove the old chainrings or clean them thoroughly if you replace only the outer chainring to change the gear ratio.

Replacing stars

When replacing the asterisks, you need to pay attention to their relative position.

The outer star, usually the largest, has a small pin protruding from one side. The sprocket should be positioned so that the pin is behind the connecting rod in order to avoid complete seizure of the chain in the event of its dismounting and falling between the outer sprocket and the connecting rod. The inner sprocket usually has a small marking in the middle of the outer edge, which should also be placed behind the crank.

The chamfered edges of the cogs. which aid in gear shifting. either the brand name or any other markings must be visible from the outside when the sprocket is installed.

Install the sprocket with the markings outward, thereby placing the teeth correctly for smooth gear shifting. When the sprockets are positioned correctly, insert the nuts into the holes. Fix them with a special wrench or hexagons, then screw the bolt into the nut clockwise until you feel a slight resistance, while fastening the sprockets.

Repeat these steps for all bolts, then alternately tighten each bolt a quarter turn at a time until it stops. A torque wrench can be used to do this by tightening the bolts to the torque indicated on the bolts.

Install the sprocket connecting rod onto the axle, remembering to thread them through the chain. Pedal and change gears to make sure everything is working properly. If you have resized the outer sprocket, you may need to readjust the front derailleur for smoother speed changes.

How to remove a sprocket from a bike

The sprockets of a speed bike are the main parts of the gearshift system that provide the gear ratio of the drivetrain. According to the degree of influence, they are divided into leaders and followers. The first ones are located at the connecting rod pair and are called the system. The driven ones are located on the rear wheel hub and are divided into cassettes and ratchets by design.

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Over time, the stars wear out, as a result of which they need to be completely or partially replaced. The second option is more common in practice, since the wear is uneven. The most frequently used transmissions are subject to it. The problem, of course, requires a timely solution, otherwise driving will turn into torment. The chain will seize or skip worn stars. Many modern models allow you to remove the sprocket and put it separately on the system or cassette without replacing the entire assembly. Read on how to do this.

Dismantling the transmission cassette

The rear of the transmission is not too difficult to disassemble, all that is needed is time and a few tools: a cassette puller, a whip and wrenches (open-end. for removing a wheel and an adjustable. for a cassette).

The first thing to do is to free the bike from the rear wheel. Using a wrench, the nuts are unscrewed, and the chain is dropped from the rear sprockets. On a mountain bike, it is usually a matter of a second to remove and put on the wheel, thanks to the eccentric fastening.

The removable device is installed on the slotted nut of the cassette. A whip. a small flat knife with a fragment of a chain. is needed to keep the cassette from turning. With the help of an adjustable wrench, we rotate the puller, we direct the whip in the opposite direction, or, more simply, we hold it with a large star of the system.

Removing the rear wheel sprockets

To unscrew the nut, you will need to sweat a little, and not only in the first stage. With the same good effort, the stars will need to be returned to their place. Once the nut has folded, the cassette can be safely unhooked from the wheel. Now it remains to examine it and determine which star needs to be pulled out.

Some of the outer small sprockets can be removed immediately when removing the cassette. They should be cleaned and inspected for wear. The same is done with the main sprockets: it is determined how much they are worn out and which ones are the most.

How to repair a bicycle rear derailleur?

Unlike ratchets, in this system the stars can be changed individually. All that is needed is to remove the old part and put a new one in its place. Special rivets and small spacers are located between the stars, which allow them to hold a fixed position and facilitate the installation of the cassette itself. It is very easy to screw the desired star from the device, the main thing is not to get confused in the sequence, especially on large cassettes of high-speed mountain bikes.

Sometimes spiders can be found on cassettes. rigidly fixed areas of several stars. Here you will have to replace the entire set, on which one of the stars is badly worn out. True, this only applies to large transmission rear wheel sprockets.

When replacing a single chainring, you may encounter the problem of the difficulty of switching the chain to it. This is due to the fact that the chain already has wear compared to the new sprocket. And if this is not so noticeable with one detail, then several new stars will immediately bring a tangible dissonance to the operation of the transmission. That is why it is advisable to change the cassette at the same time as the chain.

How to remove rear sprockets from a bike?

A bicycle is a means of transportation, driven by the physical strength of a person. This is how you can describe the essence in technical words. In fact, he is a friend from childhood. As soon as we begin to grow up and understand something, we drag our parents to where we can choose a bike and shouting: Buy !!, in the end we proudly roll home a new product, while we still do not suspect that any equipment needs care and that it can break. In order to adjust the bearings on the rear hub, in order to replace a worn sprocket, and sometimes to replace a broken spokes in the rear wheel, it is necessary to remove the cassette with sprockets. It’s not that hard to do.

How to remove sprockets from the rear wheel of a bicycle: step by step instructions

With active riding, the bike gradually wears out. To avoid this, you must constantly look after him. On high-speed bikes, one of the most vulnerable spots is the rear of the drivetrain. Therefore, sometimes it needs to be replaced. How to remove sprockets from the rear wheel of a bicycle?

How to remove sprockets from the rear wheel of a bicycle without a puller?

For such an operation, you do not need to purchase a special tool. True, it is much easier to deal with him. In order to remove the ratchet without a puller, you will need:

  • gas wrench;
  • center punch;
  • a hammer.

The ratchet has 2 slots. You need to insert a center punch there and hit it with a hammer. You need to direct it clockwise. You can use a large nail instead. You have to be careful, as there are bearings under this place. With a little effort, you can screw the sprockets.

There is still the inside of the ratchet. It is removed with a gas wrench, which is turned counterclockwise.

How to remove rear sprockets from a bike

The bike drivetrain requires periodic maintenance. The most common problems are chain wear and failure of one or more sprockets on the cassette. Wear is also true for a single-speed one, the only difference is that the chain and the star itself are designed for longer operation.

The worn out part of the transmission negatively affects its entire operation, therefore the used sprocket will need to be replaced. Especially this problem pops up on asterisks, which are used too often, which, in principle, is logical. Before changing, it is necessary to remove the worn out sprocket from the rear wheel, which we will talk about further.

How to remove and put a system star

The system is a set of three chainrings. If you often have to ride at speed, then most likely the largest sprocket will wear out. Conversely, with frequent off-road trips, wear will affect the first (smallest) sprocket. By analogy with the second, middle sprocket, when the bike is used at medium speeds in conditions of a dirt road or bad asphalt.

On a modern mountain or road bike, the system is collapsible, so it will not be difficult to dismantle all the stars. Before work, you need to carefully prepare, namely, collect all the necessary tools:

  • connecting rod puller;
  • spanner key;
  • hexagons;
  • new detail;
  • clean cloth and grease.

Removing the system from the bike: 1. Place the frame in an upright position. If you have a stand, you should definitely use it.

Remove the right crankshaft axle fixing bolt with a hexagon.

Unscrew the pedal from the right crank arm. A standard open-end wrench is suitable for this.

Insert the puller into the connecting rod to remove it from the carriage. To begin with, we screw the tool all the way into the thread. It is important that it sits flat on the shaft, otherwise the axle can be damaged when unscrewing the connecting rod. Place the spanner wrench on the puller and screw it in until it stops until the connecting rod is pushed out of the carriage shaft.

The two stars are usually attached to each other on a so-called spider. The big one remains on the connecting rod itself. Unscrew them with the hex bolts.

This is how the system understands. Replacing and installing looks like the reverse process:

  • Place the desired sprocket on the spider and tighten the fasteners. Change the large part together with the right connecting rod and screw the medium and small sprockets onto it.
  • Next is the installation of the connecting rod on the carriage. Before this, it is advisable to clean and lubricate the carriage shaft.
  • Carefully place the chain on the system and screw in the connecting rod by rotating the puller in the opposite direction.
  • Tighten the fixing nuts and fit the plugs.
  • Screw the pedal onto the connecting rod.

When replacing one star, it is advisable to clean the old ones. Lightly grease the system components before installing on the carriage.

So just replace the chainring. All of the listed tools are required. The connecting rod is a delicate thing, and a hammer and chisel is not the best option for removing it. The same goes for keys. It is difficult to replace them with pliers, besides, it can easily eat nuts. Well, without hexagons, it is impossible to disassemble the system into parts.

At the end, check the operation of the transmission. whether everything is in order and whether it is necessary to adjust the speed switch.

How to remove scrolls on a bike

Causes of pedaling on a bicycle and their elimination

Why pedals on a bike? Most cycling enthusiasts face a similar problem. But even if you are a beginner and only recently purchased a bike, you should definitely know what the problem is, how to avoid it and what to do in such a situation.

Pedals on a speed bike

Scrolling on a high-speed bike is a possible defect in the rear wheel of a bicycle, which is most often found on new road models.

In order to get rid of the causes that spoil your vehicle, it is necessary to determine the degree of contamination and wear.

  • Remove the cassette from the bike.
  • Clean all chain links with a flat bristle brush.
  • With a napkin, which is moistened in kerosene, you need to wipe all washers and existing teeth.

If the pedals are cranking on sports vehicles, you need to change parts that could be damaged: sprocket, chain, ratchet or bushing.

It is much easier to repair and replace components on a simple bicycle than on other types of vehicles. The express one needs to replace several elements of the chain, as it is more complicated.

There is no vehicle that can do without specialized maintenance.

Why are the bike scrolled

At the same time, it is difficult to determine the existing deviation by eye and make repairs correctly. In order to figure out how to fix the problems due to which the pedals on the bike are scrolling, it is necessary to determine the reasons.

The resulting trouble may be the result of the following possible reasons:

  • wear has occurred, or, more simply, the rear sprocket has worn out;
  • the chain on the racing transport is strongly deformed and stretched;
  • the rear wheel hub and its elements have become simply unusable and faulty.

All of the above problems cannot be asymptomatic, so you should carefully look at your bike and remember the following: if the wheels begin to spin poorly, the free wheeling has increased, the chain in places or often slips while driving, it is necessary to carry out urgent diagnostics and find the reason for the pedaling.

Most often, when a breakdown is detected, they begin to check the pedal mechanism itself. But this is not always correct and correct, because a malfunction can arise directly in other parts and details of the entire mechanism guiding the movement:

The first reason for pedaling is possible on a speed bike, road bike, and a bike with a foot brake. With long-term use of transport, the hub on a bicycle and all its components can wear out, while losing engagement with each other. The process of rotation of the wheel continues, however, the links do not come into contact with each other, creating an idle, as a result of which scrolling is formed. The crux of the problem lies in the pedaling of the stars, but not the wheels.

How to remove scrolling on a bike

The first step is to completely lubricate the chain mechanism and clean out all dirt. Pay attention to the space between the rollers and the sprockets. Before starting to repair the chain, it is necessary to remove the rear wheel, because without this procedure it will not be possible to dismantle the transmission.

The next step is to replace the sprocket and associated chain. Replacement must be done in a comprehensive manner, otherwise all repairs will go down the drain and pedal overshoot on a regular bike will be a constant and long-term phenomenon.

How to fix this kind of breakdown? It is enough just to dismantle and remove the wheel, disassemble the hub mechanism into separate spokes, inspect and evaluate the parts of the hub, roller and cone axle for possible wear.

You can, of course, try to take the cone to a specialized workshop for grinding, but this will be a waste of time, because the wear will not be eliminated in this way. It is necessary to completely change parts.

How to care for your bike chain to avoid scrolling

Be that as it may, the main reason for the appearance of scrolling is the chain. To avoid such problems, the chain must be looked after, and this must be done in several approaches.

Flushing. After each trip (or after several, if you are lazy), the chain must be washed and cleaned of dirt. Several substances can be used for washing. special cleaning agents, kerosene and white spirit. Before processing, the chain must be cleaned of dirt. It must be removed, rinsed in any container, and then rinsed with a cleaner.

Important! Do not use gasoline for washing. it negatively affects the chain, can oxidize it or cause rust.

Lubrication. After washing, the chain must be relubricated. A wide variety of lubricants can be used for this, most often LITOL 24 is used (the most difficult option due to its high density), liquid lubricants in oilers, aerosol lubricants. It is worth choosing a lubricant carefully. high-quality substances are not washed off with water, are resistant to large fragments of dirt, reliably protect the chain from any intrusion.

Whichever option you choose, it is worth discussing it with professionals if the chain has never been lubricated before.

Pedaling: what are the problems and what are the causes

If a malfunction occurs for the first time, it can be difficult to determine what exactly it is. Signs of a pedaling problem:

  • The wheel is not spinning or is not spinning enough;
  • The bike chain slips while riding;
  • Increase in freewheel.

In general, the reasons why the pedals on the bike are spinning are as follows:

  • Bicycle sprocket cranks are worn. There is no need to undergo a technical inspection to establish this reason: the problem is obvious. When worn, the cranks on the sprocket appear worn and worn. A similar problem can arise from natural causes: the bike is simply old enough and already worn out. Or, while riding, the cyclist exerts too much force by applying excessive pressure on the pedals.
  • Why does the rear sprocket spin on a bike? The reason may also lie in the lack of regular technical inspection and insufficient washing: perhaps the sprocket on the bike is simply dirty.
  • Chain problem, which is one of the most common. The reason, as in the case of the wear of the sprocket cranks, may lie in the old age of the bike and not in regular maintenance. Perhaps the chain just needs washing and sufficient lubrication;
  • Rear ratchet problems can be due to several reasons. Many people sin using too much oil or grease with an increased thickness. This could cause the ratchet to malfunction. It can also be caused by dirt and dust mixed with oil, or a broken bearing.

Bicycle sprocket crank problems: what to do

We Still Don’t Know How Bicycles Work

Once you’ve identified the source of the problem. the cranks. and figured out the cause, you can start fixing it. The simplest case is sprocket contamination. Just rinse the parts thoroughly, wipe with a dry, lint-free cloth and let dry. Never lubricate parts with wet! After thoroughly drying, you can lubricate with special oil. An important point: there should not be too much grease, otherwise it will again lead to malfunctions.

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If the sprocket is lapped, then it must be removed, disassembled, cleaned of dirt. A worn sprocket may need to be replaced or sharpened. Even if the sprocket on the bike can be repaired, then it will not last long, so it is better to spend money on repairs right away. If you have never done anything like this before and you are worried about scrolling on the bike, repair is the best solution.

Solving Rear Ratchet and Chain Problems on Bicycle

As in the previous case, the ratchet must be thoroughly cleaned, dried and lubricated. perhaps this will be enough. If not, the problem of wear of individual ratchet sprockets is solved by replacing them. In addition to sprockets for replacement at home, a key is purchased.

Lubricate the chain after cleaning it, you need to drip a drop onto each (this is important) link of the part. Look carefully to see if the chain has bent links. If there is, then they must be carefully brought back to their original position. If the chain is stretched or worn too much, then it must be replaced with a new part.

In some cases, replacing a new chain does not solve the problem, and pedaling continues as the new part is not similar enough to the old ones.

In this case, you need to either use the bike until the problem is solved on its own (the chain reaches a certain level of wear), or (which is preferable), replace the entire transmission in a repair shop. A transmission is the mechanism that sets a bicycle in motion. It includes sprockets, chain and cassette (rear sprockets).

What to do to avoid pedaling?

Avoid greases that are too thick or old.

As you can see, many problems with a bicycle, including pedaling, can be solved simply: often washing and lubricating the part is enough. But even if the reason lies in something more, the problem of scrolling is solved quite simply and everyone can do it. Do not forget to regularly wash and lubricate the iron horse, as well as regularly carry out maintenance, and your bike will delight you for a long time.

How to pump a press for men at home: tips and photos

Alas, not everyone was awarded by Mother Nature with a toned body with 6 cubes. If you want to look great and pump up your abs, we recommend doing the exercises below. Their advantage is that you can do them even at home, you do not have to spend time and money visiting the gym.

Home abs for men: the best exercises

You do not need to do them every day, it is enough 2 times a week for 15 minutes. Also, do not forget to pay attention to other parts of the body so that it looks harmonious and masculine.

If you think exercise alone will help you build cubes, you are wrong. You should also monitor your diet. forget about harmful foods, when you use them, your belly will be just as flabby, even if you pump your abs.

Food rules that you must remember:

  • Eat only slow carbohydrates and forget about fast ones. Include cereals, grains and seeds on the menu
  • Eat as many fresh vegetables and herbs as possible, fruits. in small quantities
  • Give preference to lean meat, it contains a maximum of protein and a minimum of bad cholesterol
  • Choose fats wisely. forget about fried, margarine and butter. Eat unrefined vegetable oils, fish oil, avocado, seeds.
  • Eat small meals every 3-4 hours, at least

Best Abs Workout Program for Men

asterisk, works, bicycle

Plank. This is one of the best exercises, it works all the abdominal muscles. It will also help you strengthen your back, legs and buttocks, as well as your shoulders. Follow three approaches, try to hold out in this position, as indicated in the photo, as long as possible. You will get better every time.

You’ll love our article Plank Exercise: How To Do

Climber. The exercise is so called because it resembles the movement of a climber who climbs to the top. It will strengthen your heart, abs, and glutes. Take the same position as for the push-ups, now bring your right knee to your chest, return to the starting position. Repeat with the right leg as if you are climbing a mountain, start accelerating.

Raising the legs and trunk. One of the easiest exercises to perform, but no less effective. You need to lie down and raise your legs and torso at the same time at an angle of 90 degrees. Make sure that your back and legs are straight, do not bend them. Do 15 reps in 3 sets. Do the lifts slowly, watch your movements and take your time.

With press roller. It is inexpensive, and the result is amazing! But it is not so easy to deal with it, refuse to use it if you have back problems.

Kneel on the mat, grasp the wheel with your hands and slowly stretch your body forward, then return again in the same way to the starting position.

Bicycle. This exercise has been familiar to us since childhood. Lie on your back, bend your knees, arms behind your head. Round your back and lift the upper part a little. Now start doing movements with your legs bent at the knees, as if you were riding a bicycle.

Above, we have presented you some of the most effective and efficient exercises for your abs. Performing them regularly and eating right, you will notice the effect after a couple of weeks. Success!

How to pump up the press at home for a man?

Many men are interested in the question: how to pump up the press at home for a man? In order to have a relief and beautiful abs, it is not at all necessary to go to the gym, but it is enough to carry out 2-3 workouts for the abdominal muscles per week. In this article, we will analyze the training program. how to pump up the press at home for a man. The workout takes no more than 30-40 minutes a day. If you need to remove the belly, then some abdominal exercises are indispensable, because it has long been clear to everyone that local fat burning is impossible, and fat burns out evenly throughout the body. You may even know how to pump up a man’s abs at home, and even pump him up to cubes, but no one will see him behind a thick layer of fat. Therefore, it is worth taking care and burning excess fat.

The press is divided into: lower, upper and lateral (oblique muscles of the press).

Program: how to pump up the press at home for a man

Starting position: lying on your back, arms extended along the body.Exercise: slowly raise your legs perpendicular to the floor, then return to the starting position. In this exercise, the main load falls on the lower press. We perform 3-4 sets of 30 repetitions.

Exercise. Lying leg raises one at a time

Starting position: lying on your back, arms extended along the body. Performing the exercise: this is basically the same exercise 1, but here you need to raise your legs not simultaneously, but in turn. First, we perform 15 repetitions on one leg, then 15 on the other. If you find it difficult to perform the exercise, start with this, as it is easier. We perform 3-4 sets of 30 repetitions. You already know two exercises, and you already practically know how to pump up the press at home for a man.

Exercise. Alternate Twisting

Starting position: lying on your back, hands behind your head, legs bent at the knees Exercise: do twisting. touch your right knee with your left elbow and vice versa. This movement most of all involves the oblique muscles of the press. Do 4 sets of 40 reps.

A well-known movement, perfect for home workouts. The effectiveness of this movement has been tested by time. We perform 3-4 approaches to the maximum.

The vacuum exercise was practiced by Arnold Schwarzenegger himself. The essence of the exercise is as follows: get on all fours, your back is straight. We take a deep breath and relax the abdominal muscles and try to draw in the stomach as much as possible. Breathe through your nose and don’t hold your breath. Do the exercise for about 12 repetitions.

Lying on the floor, simultaneously raise the body and legs. In this exercise, almost all abdominal muscles work. We perform 3-4 sets of 12-15 repetitions.

Exercise. Hanging leg raises on the bar

In this exercise, the lower press works the most. It is very effective, but also the most difficult.

Disassembled seven exercises are the most effective and popular. Choose the most suitable for you and do them 2-3 times a week. It is possible to alternate them weekly. Such a press workout will allow you to pump up the abs at home over time, and you will no longer ask the question of how to pump up the press at home for a man.?

If you need to remove a few extra pounds, then running should be added to this training program, but if this is not possible, then press training should be performed with maximum impact and high intensity (we increase either the number of approaches or the number of repetitions). To burn excess fat, you just need anaerobic exercise (walking, running, cycling), as well as a correct and balanced diet.

Classification of cassettes

By design

Dismountable. the cassette is assembled from individual sprockets fastened with rivets or screws. The easiest and hardest option. It is theoretically possible to replace individual stars in a cassette if the package of stars can be divided.

On a spider. Stars in the form of rings are attached to a center bushing made of light alloy (spider) with ray mountings. The system is lighter than collapsible, but more expensive. The advantages of the design include high resistance to pollution.

Several spiders. The stars are fastened in groups of 2-3 pieces, each group on its own spider. The advantages of this scheme include the ease of replacing worn out star groups without changing the entire cassette.

OpenGlide. Developed by SRAM’s road bike brand. The cassette is assembled as a cone hollow inside from individual ring-shaped stars. There are only two points of attachment of the cassette to the hub. through the largest and smallest sprocket of the usual shape. Very lightweight and very expensive construction.

X-Dome is an evolution of SRAM OpenGlide technology, used in SRAM XX cassettes. Ultimately lightweight but also extremely expensive system. The large sprocket of the system is made of aluminum with slots for mounting on the bushing. The smaller stars are machined from a single piece of steel in the shape of a hollow cone that attaches to the largest and smallest stars. The cassette is installed on the bushing through the splines on the outer stars. A very expensive design that wears out almost faster than the cheapest steel bag.

Bike cassette

A bicycle cassette is a multi-sprocket assembly on the rear axle of a modern bicycle. The kit is fastened with projections (slots) on the inner surface of the cassette, which engage with the counter projections on the rear hub drum. This mounting method is called slotted. The cassette is locked against turning by the slots, and the stop nut prevents displacement along the axis of the bushing. Rigid fastening of the cassette to the axle is necessary for reliable transmission of torque from the pedals to the rear wheel.

The bike ratchet is part of the drivetrain. The ratchet system appeared earlier, but today it is gradually giving way to a more progressive cassette system. In fact, this is the same package of sprockets as in the first case, but combined (through a ratchet mechanism) with the bushing into one piece. When free running or rotating in the opposite direction, the ratchet emits a crackle, for this feature the design was named.

Ratchets are often found on cheap and old bicycles. A ratchet usually contains fewer gears than a cassette and is less reliable. When hitting hard obstacles, jumping, the chance of bending or breaking the rear hub on a ratchet bike is much higher compared to a cassette system due to the design of the ratchet. In addition, if the sprockets in the cassette are worn out, it is possible to replace an individual sprocket from the cassette set. With a ratchet, such manipulations are difficult.

Among the pluses of the ratchet. the price is lower, however, the reliability is also lower. Cassette and ratchet are not compatible with each other. If you want to change from one system to another, you will also need to change the rear hub. Typically, a cassette has more gears than a ratchet. In addition, on mass ratchets, the minimum sprocket usually contains 14 teeth, on cassettes, small sprockets of 11-12 teeth are used.

Ratchets differ in the number of stars in the set and the number of teeth on the stars. 6-star ratchets with 14-28 teeth (the type is called 14-28T) are considered mass, 7-star ratchets (14-34T) are also often found. The procedure for replacing a ratchet requires the use of a special tool. a ratchet puller and is difficult to perform in the field. In addition, due to the design features of the attachment on the axle, when dismantling the ratchet, much greater physical effort is required than when dismantling the cassette.

Cassettes are also divided into groups according to the number of stars in the package, as well as the minimum and maximum number of teeth for the stars in the cassette. For example, marking 11-36T 10 speed means that we have a cassette of 10 stars with a range from 11 teeth on the smallest chainring to 36 on the largest. If we are talking about cassettes for roadways, then they can be compatible with one of two systems. SHIMANO or Compagnolo. Cassettes from other manufacturers may or may not be compatible with the two major standards.

Depending on the type of bike

Mountain bikes are fitted with cassettes with sprocket ranges from 11-28T to 11-36T, 8-10 stars.

Road bikes have a sprocket range of 11 (12). 22T to 11 (12). 27T, cassette 8-11 stars. The 12-27T cassette is considered to be intermediate between road and mountain packages.

Road bike cassettes, excluding Compagnolo, interchangeable with mountain bike cassettes, with the same number of stars in the cassette.

By the number of stars in the package

A modern cassette can have 7 to 12 stars. Most common cassettes with 8-10 stars.

Depending on the materials used

Steel stars. The vast majority of cassettes are made of chrome-molybdenum steel. Inexpensive and not the most durable option.

Titanium based alloy. Finds use in more advanced designs, often only on large stars. The cost is higher than that of steel, the weight is less. There is no consensus about the superiority in durability of titanium cassettes compared to high-quality steel cassettes.

Anodized aluminum alloy. Super lightweight cassettes for high-end competition. They weigh very little, the cost is the highest of all possible, they wear out extremely quickly. Durability at the level of the simplest steel cassettes.