Varieties and main constituent elements
Hubs are divided into two types. front and rear. The front ones are used exclusively for fixing the wheel. They act as a kind of attachment and axis of rotation of this element.
The rear hub of a bicycle is used not only to secure the wheel, but also to transmit power from the pedals. Therefore, it has high mechanical loads, it is on it that the parameters largely depend.
Bicycle rear hubs differ in materials used for manufacture, design and some other parameters. Several varieties of these parts are now on sale:
- Planetary. They use an internal gear selector and the main elements are located inside the housing. These parts are very reliable and do not require regular maintenance. Their only drawback is their high cost.
- Ratchet. They use a set of sprockets that are connected by a ratchet mechanism. Today these are the simplest and cheapest parts, they are installed in inexpensive bikes.
- Cassette. In these, the rear stars are placed in the drum.
The last two options are considered the most common on the market. This fact is due to their cost. Parts of the planetary type are much less common on the market. They are reliable, but they cost a lot and can only be seen in some city bikes.
Rear wheel ratchet bushings are the cheapest and most widely available on the market. But it is better to choose cassette parts. They are more expensive, but much more reliable than models with a ratchet.
Calculating the length of the spokes
Calculating the spokes for a bicycle wheel is an important, serious matter that requires accuracy and precision. Well, sort of like that. Take measurements with a vernier caliper with an accuracy of tenths :).
A serious article that inspires confidence in its appearance is posted in the same place as Sheldon’s manual on assembling wheels, so at first I did not pay attention to the fact that the author of this note on the spokes was not SB.
I read it thoughtfully, stuck it into trigonometry at the end of the article. Measured the hub and rim.
Rear hub Shimano Parallax FH-RM60 dimensions: from the right nut to the flange 46.5 mm, from the left nut to the flange 30.5 mm, from nut to nut (hub width) 135 mm, the diameter of both flanges at the centers of the holes for the spoke 45, 5 mm, diameter of the hole for the spoke 2.5 mm, the thickness of the flange along the axis of the hole of the spoke 3.2 mm.
Rodi Vision 3 559 × 19 rim dimensions: effective diameter 540.2 mm, hole offset no more than 1 mm.
I used these figures to calculate. For the formula given in the article mentioned above, I put a leaf in Excel, and used the online calculators as they are. Then XYNTA overtook me:
The results were very mixed. Twice Just in case, I divided the result of the calculation by the formula from the article by two and wrote it down on a piece of paper, at the top.
There is still a difference of about 5 mm, which is a large tolerance for the length of the spoke.
Having smashed my head a little, I found the first part of the problem. the formula in the article is wrong! The author takes the value of ERD and D as it is, and from the drawing it can be seen that they need to be divided in half before this, turning the diameter into a radius.
How To Remove Install Replace the Rear Wheel On a Bicycle
After another hour of thought, I thought to see how the ex-fur-tree calculates the cosine of the angle. Sure! He perceived the argument as radians, not degrees after that both results. uncorrected from the article and the final from the calculators. converged, at lengths of 264 and 262 mm.
However, in the article, after calculating by the formula, it was also proposed to make an amendment for the location of the spoke in the hole, as well as for the lengthening of the spoke when pulled. With this in mind, I needed knitting needles with a length of 262 and 260 mm, respectively.
Thus, all the necessary raw materials were finally purchased, and the equipment was prepared. About the assembly process. in the next part.
The lacing is the order in which the hub, rim and spokes are locked. It can be radial or cross. Radial provides for the installation of the hub without crossing the spokes with each other. Crossing the needles occurs.
The hub is located in the center of the wheels and is attached to the bike frame. Provides wheel rotation, eliminating slippage and turning. Rear hub helps roll the bike. efficient travel without wasting energy.
Bicycle rear hub design provides the following configurations:
- the presence of a free wheeling, lack of a braking mechanism;
- lack of free play, the presence of a brake mechanism;
- the presence of a free wheeling and braking mechanism.
The dimensions of the hub, its weight and quality affect the ride and energy consumption of the cyclist while riding. There are three types of this node.
- Ratchet Hub. Modern rear hub allows cassette sprockets to be mounted on the drum. The bearings are located closer to the middle, which negatively affects the uniformity of the load distribution. It is customary to complete teenage and inexpensive bicycle models with such bushings.
- The cassette hub is another modern mechanism option. In this case, the cassette is fixed by means of the slots located on the sleeve. Such bushings are reliable and can withstand loads of up to 120 kg, since the bearings in them are located closer to the edge a design that combines the functions of a hub and a speed switch. The device of the rear wheel hub of this type of bicycle is rather complicated: the mechanism is closed by a case, which protects it from dust and moisture. At the same time, when working with it, the chain will last longer, since it does not change the position for switching speed.
The 3-speed hub has a simple design, while the 5- or 7-speed gears are best left unassembled. Gears of planetary systems are installed in a certain position during assembly. Such work requires special equipment.
If this problem occurs, the flare nuts are overtightened. You need to repeat the steps described above, but now weaken these elements a little. In the absence of timely maintenance, gradual destruction of the bushing is possible.
REAR WHEEL REPAIR: REMOVE THE PUNCH
To begin with, it should be said that repairing the rear wheel of a bicycle can also be associated with the elimination of the figure eight on the wheel or the filling of the wheel hub. However, since these are specific operations that require certain experience and tools, they deserve separate consideration, and will not be described in this text. Below we will tell you how to cope with a puncture of the rear wheel, since everyone can face this.
Before you start repairing a wheel, you need to dismantle it. The front wheel can be removed easily, but removing the rear wheel, for a beginner bike enthusiast, may not be such an easy task. Let’s take a closer look at how to dismantle the rear wheel.
Removing the front wheel from a bike?
Before starting dismantling work, it is necessary to determine the type of braking device. No prior steps required for disk hardware.
For rim structures, the brake must be released before removing the wheel from the bike.
The technology is similar for models of different companies: it is necessary to squeeze the pads and pull out the arc by unscrewing the screw holding it. The following actions can be divided into several stages:
- Turn the bike over with the wheels up. To avoid damage to the equipment, you can place a soft base. Prolonged exposure to disc models in this position may threaten air from entering the tubes, so all actions must be carried out quickly and accurately.
- Unscrew the nut or eccentric depending on the vehicle model.
- Pull upwards and remove the wheel from the mountings. Remember that when working with a disc brake, pressing the handle without a wheel may result in the pads being compressed.
After carrying out repair work, you need to install the spare parts back. This requires information on how to assemble a bicycle wheel? It is enough to carry out all the steps in reverse order:
- Insert into the mount, observing the directions of rotation.
- Secure with eccentric or nut.
- Flip to normal position.
- Install the rim brakes.
Observing all the points of the instructions, it is not at all difficult to master the disassembly and assembly of the wheel mechanism. After carrying out the work two or three times, a skill is acquired and the speed of the procedure increases.
how I changed the back tire and tube on my kid’s bike
How to change the rear wheel on a speed bike
Without a bicycle in the country, nowhere. In the literal sense of the word. not to go anywhere. Not for a loaf, not for self-tapping screws, not for matches. In addition, if there is no car.
And if there is a car, and the driver tasted the aromatic apple Calvados in the morning? You have to walk, which takes a lot of time. And if there is a bike, I jumped on it, and in a few minutes there will be a loaf, and self-tapping screws are bought, and matches are obtained.
Therefore, not only do you need to have cycling at your disposal, and besides, it must always be in good order, ready at any time to take you on urgent matters.
During the spring revision of my old high-speed bike, I found an eight on the rear wheel. a change in its geometry. The rim was bent so much that it constantly touched the brake pads, making it impossible to drive safely.
First we decided to tighten the knitting needles. There are special ways to do this at home. For those who are interested, it is enough to search the Internet for how to fix the eight. A closer inspection revealed that a pair of spokes was missing. The plastic spoke guard installed on the wheel makes it difficult to install new ones, so it must be completely disassembled.
Turn the bike upside down, unscrew the eccentric clamp nut, remove the eccentric itself from the hole in the axle, release the footrest, remove the chain and wheel. In this case, you need to loosen the brake pads and release air from the wheel so that the tire does not cling to them.
Unscrew the nipple, pull out one side of the tire, gently prying it with a flat screwdriver, without tearing the camera. Take out the camera, then remove the tire.
Now you need to remove the asterisk. It is impossible to do this without a special puller, so we took care of its purchase in advance.
Inserts the puller inside the sprocket and unscrew it with a gas wrench. By the way, for these purposes, any key for 24.
Our speed bike had a single rim wheel. Almost all modern bikes are equipped with double rim wheels. It is believed that they are stronger and more reliable. The difference in price is not very big, so we listened to the seller and bought a copy with a double rim.
At first, the plan for replacing the rear wheel on a speed bike seemed simple: screw the sprocket onto a new one, insert the tube, insert the tire, and mount it on the bike. But upon closer inspection, it turned out that the wheel axles are different. The old one. with a hole inside for the eccentric, and the new one. without it.
Therefore, I had to rearrange the axle from the old wheel to the new one. This requires 2 keys. We hold the locknut with one, and unscrew the other with the other. Having unscrewed, remove the washer and unscrew the locknut, which is the bearing boot. When unscrewing the nut, watch out for balls that may fall out of the gap formed. Now you can remove the axle.
In the same way, we remove the axle from the new wheel. The grease in it is fresh, thick, so the bearing balls, sticking to it, were in their place.
Carefully, adding fresh grease, insert the axle with a hole for the eccentric onto the new wheel and tighten the nuts in the reverse order.
It is necessary to tighten the nuts with a cone for the bearing until there is no play in the carriage, but at the same time the wheel rotates freely.
On both sides of the axle along the edges, we leave a space equal to 1 cm so that it fits into the eyes of the rear fork of the bicycle. This distance is adjusted by a bushing washer.
Tightening the second nut, we fix the first with a key so that it does not move, otherwise the wheel will spin with effort.
Then we collect everything in the reverse order. Install the spoke protection, use the puller to twist the asterisk.
On the one hand, fill the tire, insert the camera, fill the tire completely. We pump the chamber with a pump, then bleed the air so that it fits into place.
Now we take the wheel, put the chain on the sprocket and install the axle in the eyes of the fork. The tire, having pressed on it, must be pushed between the brake pads.
Install the footrest, insert the eccentric clip and secure it with a nut.
Let’s adjust the brakes by fixing the pads near the rim. We pump up the camera and make a test drive. This completes the replacement of the rear wheel of a sports bike.
How to disassemble and reassemble the rear wheel of a speed bike
The rear wheel of a bicycle requires maintenance more often than other components. This is due to the fact that it is the most loaded element. it is it that accounts for the bulk of the user’s weight. Those who like to ride such a vehicle often and for a long time should learn how to disassemble and assemble the rear wheel of a high-speed bike correctly. Of course, you can go to the workshop, but if you have the necessary tools, any person can do all the work on disassembly, repair and maintenance on his own, while receiving moral satisfaction and not burdening the family budget.
How to carry out the installation correctly
After carrying out the above work, you need to assemble the bushing to its original position. This is done in the following sequence: right bearings. wheel axle. cone. left bearings. stopper. washers and rivets. lock nut.
It is almost always necessary to adjust the rear hub of a bicycle after assembling. This is done only on the left side. first, the lock nut is slightly loosened with a 15 mm wrench, then it is tightened to the stop, but the cone must be held in a fixed position.
Using the described method, you can completely get rid of the backlash of the axis, at least. to reduce it to a minimum. Most likely, you will have to carry out the same operation more than once, but you need to achieve synchronous movement of the axle and wheel.
Note: slight cranking is quite acceptable, but tightening the lock nut too tight can lead to difficulty in movement.
This completes the maintenance of the rear bike sleeve. It will be necessary to check the quality of work. test the iron friend at different speeds, determine if there is a backlash, how tightly all the details are fixed, if there are any extraneous sounds. If something does not suit you, then the process of disassembling / assembling the rear hub will need to be repeated.
Maintaining the rear hub of a bike is not a daunting task. even a beginner can handle the job. But if you cannot disassemble the bushing on your own, then you need to contact a specialist. with strong pressure on the part, it can be damaged, which will require a complete replacement.
We work with the inner space of the bushing
After the axle has been removed, you need to carefully inspect it. As a rule, this part of a bicycle wears out very rarely, but in any case, you will need to thoroughly wipe it off from dirt and dust. This is done with a dry cloth, but in some cases (if heavily soiled) you can use gasoline. So, we wipe the left cone and examine the right one for fastening strength. Only after the axle walls are completely dry (if gasoline was used for processing), can new grease be applied to it.
Note: in no case should you use chain lubricant or some other lubricant for the rear hub of the bicycle. you will need to purchase a special tool. Bearings are often used for bearings. this lubricant will be the most suitable. Too thick a layer of grease should not be applied. during the operation of the bike, it will be squeezed out and actively absorb dirt, which leads to rapid wear of the part.
Replacing the bike camera
To remove the tire and remove the damaged chamber, it is necessary to remove the remaining air: the cap is unscrewed and the wheel is lowered by continuous pressing on the nipple. If there is no air in the tire, which is more often the case with punctures, then simply unscrew the cap.
To remove the tire, you need special paddles. Of course, you can pry the camera with a regular screwdriver and even a knife, but it is better to have a professional tool. With the help of assemblies, the tire is pushed on from the side opposite to the nipple. As soon as it begins to pull together, you need to pry the sides a little further, until a sufficiently free part of the tire is formed, and it can be safely pulled off the rim.
You need to tighten it very carefully so as not to damage the rim, you should not use too much force. When the tire is removed, remove the damaged camera and install a new one. The nipple is threaded into the hole in the rim, then the chamber is evenly distributed around the circumference.
Attention! The camera must lie flat, without kinks, otherwise you will have to reinstall it. There must be a flipper at the bottom of the rim to protect it from the spokes. If it is torn, you need to install a new one or get by with two layers of thin electrical tape.
On top of the rim, the outer part of the tire is put on, this time, from the side of the nipple. When installing a tire, take into account the correct direction of the tread pattern. Usually, arrows are drawn on the tires, and in the upside down state of the bike, the forward direction is backward in the lower position. However, the rear wheel of a speed mountain bike is easy to go wrong, thanks to the cassette on the side. After mounting, the camera is inflated.
How to properly disassemble, clean and lubricate the rear hub
Immediately remember one truth: any service is recommended to be carried out with a snagged sleeve. Otherwise, the chances of assembling the wheel correctly and quickly are unlikely to work. this can only be done by a person who is already experienced in servicing bicycles.
Step-by-step instructions for maintaining the rear bicycle hub:
- Remove the cassette from the axle using a whip and a puller.
- Opening the retaining ring.
- We remove all bearings and washers. Note:the sleeve can be on industrial bearings and bulk bearings, but in any case, it is very important to remember their original location in the sleeve. This rule must be observed when removing the washers.
- We carry out a careful inspection of the bearings. if they are damaged, this means the need to replace them with new parts.
- We take out the axle. it does not understand.
- We clean the body of the rear hub of the bicycle from dirt. All internal cavities must be wiped with a dry cloth.
- When installing back, each part is thoroughly lubricated, special attention should be paid to the bearings during this process.
- The last step is to install the stopper and tighten the fastening nut. It is not necessary to apply great efforts to tighten, as this can result in a problem of free wheel rotation.
Of course, everything looks quite easy and simple, but there are a lot of nuances in servicing the rear hub of a bicycle. they must be known and taken into account in the process of work:
- First, the direct disassembly of the bushing should be started only after the cassette has been removed. over, the sleeve is disassembled from the opposite side and, as a rule, it is on the left. The locknut, if any, is unscrewed with a 15 mm wrench, then the stopper is removed (again, if any).
- Secondly, you need to be extremely careful when removing the washers and rings. they will need to be laid out on a pre-prepared sheet of paper in the exact order, if this moment is overlooked, the assembly of the rear bicycle hub after cleaning and lubricating it can turn into a real torment.
- Thirdly, after twisting the housing of the rear hub, its axis will begin to give in. just at this moment the bearings will appear. And again, you need to be extremely careful when removing the bearings. the parts are small and easy to lose. We remove each bearing with a knitting needle or tweezers, carefully wipe it with a cloth soaked in kerosene or gasoline, and put it aside. Just in the process of wiping, the bearings must be carefully inspected for damage, and if there are any, then the part must be replaced.
Note: in the articles and instructions for servicing the rear hub of a bicycle, you can find a recommendation to use acetone to wipe bearings. this is permissible, but it should be borne in mind that the aroma from such a product will not be the most pleasant, and acetone can corrode the skin on the fingers. And one more thing. many kulibins, in order not to lose small bearings, use a magnet. in no case should this be done! The fact is that the bearing is magnetized and during the operation of the bicycle, iron dust is attracted to these small parts. the fact that the hub will soon become unusable can be predicted with confidence.
It is highly undesirable to confuse the left and right parts when disassembling / assembling the rear hub of a bicycle. this can lead to wheel play. If at least one ball is lost, then you will have to carry out a full replacement of the bearings. Sometimes, when opening the bushing, iron dust can be observed near the axle. this means that the bearings are completely worn out, they must be completely replaced.
Obviously, in order to repair a wheel, it must be removed from the bike. For this, it is better to put the latter on the handlebar and saddle, after removing the attachments. There are two ways to fix the wheel to the frame:
- an eccentric through the hollow axis;
- nuts or lambs.
In the first case, you just need to turn the eccentric lever 180 degrees and then unscrew the nut on the opposite side of the axle. In the case of an eccentric attachment, the axle of the rear wheel of a bicycle on one side does not extend beyond the thickness of the fork in which it is installed. Experienced users must take this point into account when repairing. In the second case, the rear wheel hub axle is always longer than the distance between the fork stays by at least 15–20 mm. Thus, the axle extension beyond the outer side of the fork should be no less than 5-6 mm on each side. It is important to observe these ratios when re-assembling the rear wheel hub. After the fasteners are removed or loosened, the chain must be dropped from the drive sprocket and the wheel can be removed. If the bike is equipped not with disc brakes, but with rim brakes, then most likely you will need to dissolve them by throwing off the brake cable from the traction.
Removing the cassette and bulkhead bushing
A hub is one part of a bicycle wheel that requires periodic maintenance. On average, you need to look into it once every 2000 km of run, in terms of time it is 2-3 months of active driving. If the wheel is already creaking and there is a decrease in the efficiency of rotation, in other words, the great rides worse, then it’s time to remove it and inspect the hub.
The main problems with the bushing are backlash and insufficient lubrication of the bearings. Due to a violation of the fit or increased friction, the parts begin to wear out rapidly. If the wheel has not been serviced for a long time, the bearings may crumble altogether. To gain access to the bearings of the hub, you will need to temporarily get rid of the rear sprockets.
The rear speed device is removed using a puller and a so-called whip. Removing the cassette is a short-lived affair, but it will take a lot of effort to unscrew it from the wheel. In stages it looks like this:
- The stripper is inserted into the cassette nut.
- The whip holds the large star of the system so that it does not turn.
- With a wrench, the puller rotates, unscrewing the slotted nut.
- We remove the small stars that are installed on top, carefully fold them to the side along with the washers, and then remove the cassette itself.
Before disassembling the hub, you should slightly loosen the spoke tension. This can be done using a round key with knock-out holes for different diameters of the knitting needles. You need to loosen a little, a quarter of a revolution is enough. If the sleeve needs to be replaced, the spokes must be unscrewed enough to easily pull it out of the engagement.
A complete bushing replacement is required if both the axle and the bearings become unusable. However, often when the bushing is jammed, the axle is in normal condition, it is enough to change the bearings. Often, both will still serve faithfully if they are well lubricated. Proper lubrication will prevent parts from wearing out under dynamic loads.
The bulkhead of the axle part of the wheel is associated with cleaning the axle and bearing balls from dirt. The removed parts must be temporarily placed in a solvent, then allowed to dry, lubricated and reinstalled. Bearings in a skewed position must be adjusted by returning them to a straight position. However, during the backlash, the parts are already faulty, so replacement is the best option.
Take the survey
In this case, the following points should be considered:
- Rear wheel hub designs may vary in size, shape and bearing type used.
- The speed bike cassette can also be of various designs and contain from three to eleven sprockets.
- The hub through the spokes is quite rigidly connected to the wheel rim. Usually on high-speed bicycles there are either 28, 32, or 36 spokes, and the pattern of their weave can also be different.
- Mountain bike rims are usually box-shaped, as opposed to road versions that have single-tube tires. Since the weight of the outer part of the wheel is always tried to be reduced, the most common material is aluminum based alloys.
Mountain and city multi-speed bicycles usually have tube tires, and their size and tread pattern can be very different.