Types and design of bicycle hubs
Before doing anything with the bushing, you first need to understand its design. How to change the hub on a bicycle will become clear when you understand its design. All bushings have 4 main components:
- Housing. The spokes are attached to the body and connect it to the rim. The body has cups on the sides, into which the bearings are inserted, it is hollow inside. An axis passes through the body.
- Bearings. There are two types: bulk. balls fill the cups of the body; industrial bearings. the balls are housed in a closed structure and are a one-piece bearing. Sometimes there are balls of a non-closed type that are simply fastened by a metal shape. Bearings allow the housing to rotate around an axis.
- Axis. The connecting link of the bicycle and the wheels, bearings with the body revolve around it. The axis itself remains stationary. The fastening system can be nut or eccentric. An eccentric is used on vertical dropouts to facilitate wheel removal, sometimes nuts are used on cheaper models with such dropouts. Nuts are needed on horizontal dropouts where there is no chain tensioner and single speed transmission to make it easier to center the wheel and tighten the chain. The eccentric axis is hollow with a hole inside, through which the eccentric is attached.
- Retaining nuts, eccentrics, locknuts and guides. The guide is screwed onto the axle thread first so that the bearings remain in their position. The locknuts fix the position of the rail on the body. The nuts are screwed onto the axle from the outside of the dropouts to secure the wheel position. Eccentrics perform the same function.
This design completely describes the front hub, but the rear hub is also part of the transmission. Rear sprockets are attached to it. Replacing the rear hub of a bicycle does not require replacing the chainrings if they are in good working order. Rear hubs differ in the type of sprocket attachment:
The sleeves also have a different number of holes for the spokes, different flange heights, different widths or O.L.D (Over-Locknut Dimension. measurement of a locknut. Length is measured with fully tightened locknuts on the hub (not on dropouts) from one locknut to another). You need to choose the right hub for your dropout width, chainline and the number of spokes on the rim.
Disassembly and replacement of parts of the front hub of the bicycle
To carry out the parsing procedure, you need several wrenches. Wrenches 13, 14, 15, 16 and 17mm may be needed. The most commonly used wrenches are 14 and 15 mm. Sometimes a thin pair of wrenches are required to remove the small locknut and not damage the structure.
Remove the retaining nuts from the dropouts. Most often a 14 mm wrench is needed.
Remove the wheel from the bike. If you have a rim brake, you need to remove the pads so that the wheel can be removed.
Unscrew the locknuts. Here you need 2 keys, lock nuts can be for different key sizes and for different widths. It is necessary to hold one key on the thread of the guide, and unscrew the lock nut with the other.
Remove the guide and pull out the axle. At this point, the guides can be removed by hand.
Advice: if you cannot remove something, then do not rush to do it with great force, so as not to break the tool or sleeve. Perhaps some detail matched the other. With this problem, you can use the anti-procotic chemistry WD-40.
Pull out the bearings carefully. If you have them of a bulk type, then prepare the place of work so that they are not lost. The balls are not connected to anything in any way, so they can easily fall out and get lost. If you have industrial bearings, you will have to gently pry a thin plastic part with something to get to the balls.
Tip: Separate the balls from the right cup and the left cup, most likely they are already slightly deformed. In order not to propagate the deformation to another cup, it is best to always insert the bearings in their previous place.
Replace the bearings. Spread the balls evenly around the edges of the cup if you have a mound. Industrial just enough to slide into place.
Insert the axle, tighten the guides and locknuts. Make sure that the axle protrudes from the cups without distortions in length on one side. Slide the guides and locknuts onto it. If you have loose bearings, then a dilemma may arise: tighten tightly and eliminate the play, or leave play, but allow the bearings to rotate freely. If the backlash cannot be eliminated without strong twisting, then it is best to leave a small space, but not bring the hub to a state of complete deformation while driving.
Replace the wheel and tighten the nuts. Make sure that the wheel is level, without distortions.
Bicycle hub replacement
The hub is an essential part of the bike design. Both bushings support the entire weight of the rider and the bike itself. All loads during landing and impacts in case of unevenness are also taken over by the hub. Therefore, breakdowns due to which the hub is replaced on a bicycle are very common.
In this article, you will learn how to change the hub on the rear and front wheel of a bicycle, we will understand the types of bicycle hubs and talk a little about their maintenance.
In order for the bushing to last for a long time, it must be regularly serviced. Maintenance consists in cleaning the bearings and housing cups from old grease that has already collected enough dirt. Black grease indicates dirt. This grease must be changed to prevent dirt from destroying cups and bearings.
When you have completely disassembled the bushing, wipe off the old grease with a rag or paper from the bearings and bushing housing cups. Apply new grease to cups and bearings. Next, assemble the structure.
SERVICING YOUR BICYCLE BIKE WHEEL HUB BEARINGS FRONT AND REAR MANY TYPES
How to disassemble and replace a part for a rear hub on a bicycle
The rear hubs are part of the drivetrain, so they have an additional mechanism that depends on the type of bike drivetrain:
Before asking the question: how to change the hub on the rear wheel of a bicycle, you need to identify the cause of the breakdown. To do this, first disassemble it according to the instructions in accordance with the type in the bushings
Rear ratchet hub. The principle of operation is the same as with the front one, but after dismantling the wheel from the bike (after Step 2.), you need to remove the ratchet with a special puller and a wrench and continue with Step 3.
Rear hub for cassette. After dismantling the wheel (Step 2), remove the cassette with a special puller and a whip. Dismantling the drum consists in removing the locknut and the guide, after which you need to carefully remove the drum from the axis.
The fixed and single speed hubs are disassembled in the same way as the front ones, you don’t even need to remove the sprocket. If you have a BMX, then you have to remove the driver, it is removed according to the principle of a drum for a cassette. Sometimes there are single-speed bushings with a foot brake, for example, on a bicycle Ukraine, there you also need to pull out the brake mechanism.
The planetary hubs are very difficult to service due to their complex design, they usually do not require maintenance at all due to the closed mechanism. There is no single principle of maintenance of all planetary systems; each model should have its own instruction. The process is something like this: after unscrewing all the nuts, you need to remove the housing cover and remove the core. If you managed to do this, then you need to disassemble all moving mechanisms for service. It is important to remember how everything was originally, if you are doing it for the first time, so that you can collect it.
eZee Hub Motor Disassembly
Do not rush to change the entire bushing at once, first identify the breakdown. Sometimes you can get by with replacing just one part: a bearing, axle, drum, or even one nut. The cost of one part will be much lower than the whole bushing. Disassemble the bushing, identify the breakage and replace the defective part.
If the body is deformed so much that further operation of the bushing is impossible, then you will have to change it completely. In such a situation, you will have to re-spoke the wheel, i.e. remove all the knitting needles from the hub and rim and put everything back on, if you don’t mind the knitting needles, you can simply cut them off with wire cutters.
How To Remove/Clean/Degrease/Lube/Install A Freehub Body On A Bike Wheel
Restoration of the shape of the teeth cassettes
Optional procedure. Nadolba from the stretched chain, as mentioned earlier, can be carefully cut with a thin diamond file, leveling the “excess nodules” in thickness, but without touching the tooth profile itself! The teeth are all different, with different bevels and entrances, some are just slightly rotated in the plane. It is necessary to pay attention to this and try to give the tooth its original shape with all the chamfers and bald patches. Restoring the shape of the teeth will slightly improve switching, but, unfortunately, will not affect the remaining resource in any way. Photo of SRAM PG-970 cassette untreated and processed in this way:
The recommendation applies to high-end SRAM 970 and SRAM 990 PowerGlide II cassettes (differ in the presence of a “spider” in the second and, accordingly, in weight). Probably not worth trying to do something with the teeth of inexpensive anodized or chrome cassettes of the Shimano Deore, Road 105, SRAM PG-950, 980 and lower classes. The basis of the star in these cassettes. mild steel that deforms easily on its own, and peeling off the chrome plating will not lead to anything good. A new cassette of this class will cost less than 500 rubles, it is easier to change. Or buy something of a higher class.
Drum assembly (freehub)
After cleaning and drying, we put everything back. The assembly is simple, but the assembly order must be observed correctly. Put the lubricant in moderation, not a lot and not a little. The excess will climb out and collect all the dirt. To assemble the bearing, you need to apply grease to the groove and carefully stick the balls onto the grease. Holds confidently, checked.
Then the balls are carefully placed on the other side with tweezers. Then the spacer rings are placed on top, first thin, then thick, then a slotted ring (support bearing) is screwed on. thread LEFT!
We install the freehab on the bushing, do not forget to check if the rubber gland is in place on the inside and if you forgot the washer; tighten with a hexagon well. Freehab should spin freely without jamming and backlash; in the opposite direction is clearly fixed.
- a pair of special thin “tapered” keys 13-14-15-6 and 13-14-15-17, made of strong tool steel;
- special key-whip with a piece of chain to fix the cassette;
- cassette remover (ribbed sleeve);
- open-end wrench for 24, which can be replaced with anything;
- hexagon 1.5mm (for complete disassembly or pulling the cassette);
- hexagon 10mm (for removing the freewheel drum);
- ordinary bicycle universal key HVZ, in which you will need a convenient end between horns 10 and 12 as a drum puller
- medical tweezers (take the balls out of the kerosene and put them in the holder)
- old toothbrush (more convenient to wash);
- medium pliers (pliers).
How the hub is disassembled on a bicycle
We are talking about classic bulk bushings, where the rolling bearings are formed by separate balls, and the bearing housings are formed by the bushing elements. These are, as a rule, Shimano, Compagnolo hubs, as well as the KhVZ plant made in the USSR (a copy of the first two). In the article, the Shimaho Deore FH-M510 bushing made in Japan, produced in 2003 with a mileage of about 10,000 km, was prevented.
It should be noted that this operation is almost never done in bicycle shops during seasonal maintenance, citing complexity. suggest not to touch or replace the bushings or even the wheels entirely with new ones. However, firstly, it is simply unprofitable to do this with high-end components, and secondly, even new components from some manufacturers do not interfere with inspecting, sometimes adjusting, or even replacing the lubricant with a more suitable one for our harsh conditions. Even in industrial bearings, the lubricant requires replacement, and with the ease of disassembling the bulk bushings, it is not a problem at all to do seasonal maintenance, replace the lubricant and get a perfectly rolling bike.
All of the techniques described below also apply to inexpensive road bikes (city bikes). The design of the units is similar, the only difference is in the quality of materials, the presence of anthers and design tweaks. The cheaper the components. the easier it is to understand and the more standard the tool.
Drum disassembly (freehub)
To remove the drum from the hub body, use a 10 hex wrench (in Shimano XT / XTR hubs. 14). The thread is ordinary (right). In addition, the drum can only be removed from the spoked wheel, because it is otherwise very problematic to hold the sleeve. It is necessary to rest and, holding the wheel, turn the hexagon according to the rule of the right thread, unscrew the sleeve towards ourselves. Effort may take considerable.
After the retaining sleeve is unscrewed with a hexagon, the drum is removed and a thin rubber seal is found on the back. It can be pry off with tweezers or a sharp object and carefully removed, then the balls of the lower support bearing will be visible.
ATTENTION! DRUM SUPPORT BEARING THREAD. LEFT! careful with dogs and springs. they tend to fly apart in different directions during hasty disassembly.
Shimano Deore Drum Balls: Outside. 25 pcs. and the inside. 25 pcs. diameter 3.17mm (1/8 “).
Remember, the balls will fall out as soon as the halves of the case move relative to each other, so act accutationally and over the cuvette so that they spill out into a limited container and do not have to look all over the floor.
The drum contains spacer rings that regulate the backlash. On the picture. thick spacer ring 2.35mm and three thin adjusting rings: one 0.15mm and two each 0.10mm. If the drum has a little backlash, and it often happens that at the factory they prefer to put on an extra ring in order to simplify the adjustment, then one ring can be removed. The drum should not play, “overwrite”. also.
Features of bushings
Minus. requires straight arms, some information and accuracy when disassembling, so as not to lose parts. It also takes patience to rebuild the thrust bearings after assembly, but that patience will pay off handsomely. properly lubricated well adjusted bulk sleeves roll better!
When installing the axle, proceed according to the following algorithm: first, you need to assemble the side of the axle that is on the side of the cassette (parts 3-9), focusing on the distance from the end of the axle to the nut 5mm. Pull out a pair of cones (9) immediately. nut (3) with wrenches, locking. Then put grease into the bushing on both sides, level it with a spatula, stick balls on the grease, seat the boot on the bushing and carefully insert the axle from the side of the cassette. Then screw on the cone (11), spacer (12), washer (13) and nut (3). Now you can adjust the backlash and then remember to counter the second pair of cones.
Rear Wheel Hub Repair Basics
Rear hub breakage is one of the main causes of wheel assembly failure. Of the main reasons, one can single out both weakening and strong tightening of the cone assembly. As a result, the user can feel both a strong backlash and difficult rotation of the wheel with a crackling bearing. But in both cases, the only correct solution would be repair.
To do this, you need a set of 15 and 17 mm open-end wrenches. The first step is to loosen the locknut, which is the main nut backstop locking element. After that, depending on the malfunction, we loosen or vice versa tighten the flare nut. The ideal option would be a good and smooth wheel travel without visible backlash. After the end of the process, turn the locknut to its original position.
Often, on inexpensive bicycles, deformation of the rear hub axle can be observed. This is due to the poor quality of the parts. This malfunction is very easy to fix by replacing a better quality part. Such defects can be avoided by carrying out routine maintenance of your pet, which consists in cleaning and lubricating the mating elements. Bearings or seals have to be changed much less often.
With infrequent lubrication or if the axle is bent, the bearings can make grooves in the wheel hub. To eliminate this defect, the hub itself or even the entire wheel should be replaced, which is a costly measure.
How to disassemble and reassemble the rear wheel hub of a bicycle
Almost all modern bikes are equipped with non-brake freewheel bushings, which not only increase the speed characteristics of the bike, but also greatly facilitate the efforts applied by the cyclist to maintain the pace set by him.
The main elements of the rear bicycle hub
Let us consider in detail the structure of the classic non-brake bushing of the rear wheel of the bike. The support ball bearings of the mechanism under consideration are slightly enlarged in comparison with the samples located on the front axle. This is due to the increased load exerted by a person’s body weight.
The ratchet is installed in two ways, namely:
- screwing on the thread of the knot;
- can be mounted in a bushing.
Bushings with multi-stage ratchets were previously only used on high-speed models. Today this assembly is used on almost all modern bikes.
A feature of the pressed-on non-brake bushing is the right flange, which plays the role of the inner housing of the ratchet mechanism. This design can be seen in detail in the figure. In addition, on the flange there is a track of the bearing remote from the center. The body rotates perfectly on two freewheel elements, which are based on balls with a radius of one and a half millimeters.
The work of the ratchet consists in engaging the ratchet gears of the pawls, which transmit movement to the inner part of the ratchet body. As a result, the hub starts rotation, transmitted to the wheel, which interacts with the hard surface and provides the movement of the bike.
During the stopping of the torque acting on the ratchet, the pawls still rotate with the wheel. It was during this period that a number of bearings began to work, providing a smooth movement of the structure.
Sports bikes designed for maximum speed are most often fitted with screw-on ratchet hubs that can be removed along with a set of sprockets. This feature is very handy when repairing a rear hub or replacing one of the sprockets. In general, the designs of both ratchet mounting options are similar.
Another wheel defect can be a faulty carriage. What should you do if such a nuisance happened to you? This will require dismantling the connecting rods and the sprocket system. This is a simple process for which you should gradually loosen all nuts and other assemblies, folding them in the correct order on a clean surface to exclude dust or, even worse, sand.
If this procedure still caused difficulties, simply follow these steps:
- turn off the left locknut;
- remove the carriage cup (pay special attention to the fact that a right-hand thread is cut on this side);
- take out the carriage assembly;
- we carry out a complete cleaning and flushing of the inside of the pipe;
- we wash all the elements of the carriage system, for this it is best to use kerosene or gasoline;
- now we assemble the assembly in the reverse order;
- the last step will be to check the absence of backlash and extraneous noise, which may indicate residual phenomena of the abrasive material.
In order to completely eliminate the appearance of undesirable, and most importantly, untimely defects, it is recommended to carry out seasonal maintenance and periodic cleaning of the rear wheel working unit. These actions will significantly extend the life of your bike and help save you money.