The structure of a bicycle hub. Planetary hub for bicycle
It will be about classic loose bushings, where rolling bearings are formed by individual balls, and bearing housings are formed by bushing elements. These are, as a rule, Shimano, Compagnolo bushings, as well as the KhVZ plant manufactured in the USSR (a copy of the first two). In the article, the Shimaho Deore FH-M510 hub, made in Japan, manufactured in 2003 with a mileage of about 10,000 km, was subjected to prevention.
It should be noted that this operation is almost never done in bicycle workshops during seasonal maintenance, referring to the complexity - they suggest not touching or replacing the bushings or even the entire wheels with new ones. However, firstly, it is simply unprofitable to do this with high-class components, and secondly, even new components from some manufacturers do not interfere with inspecting, sometimes adjusting, or even replacing the lubricant with a one more suitable for our harsh conditions. Even in industrial bearings, the lubricant needs to be replaced, and with the ease of disassembling bulk bushings, seasonal maintenance, changing the lubricant and getting a perfectly rolling bike is not a problem at all.
All the techniques described below apply to inexpensive road bikes (city bikes). The design of their nodes is similar, the difference is only in the quality of materials, the presence of anthers and design tricks. The cheaper the components, the easier it is to disassemble and the more standard the tool.
Bushing features
A huge plus of these bushings is the fundamental maintainability and ease of repair in the field, the minimum required specialized tools, the ability to customize "for yourself" and, in case of problems on the road, a quick reduction to the state "you can get to the workshop." Another plus is the "honest" four (!) support bearings in a well-balanced load design, which is especially noticeable in terms of the bushing life in difficult conditions (sand, clay, snow with salt) and under heavy riders. It is especially valuable that, using the method described below, after especially dirty rides, you can quickly put the bushings in order without waiting for them to turn sour or rust.
Minus - direct hands are required, some information and accuracy when disassembling, so as not to lose spare parts. It also takes patience to rebuild the support bearings after assembly, but that patience will pay off handsomely - properly lubricated, well-adjusted loose bushings roll better!
Two bulkhead options
It is not necessary to always disassemble the bushing completely every time. As a rule, the most loaded nodes suffer - the wheel bearings, dust and sand get clogged in them, water gets there. But in a drum, for example, the probability of getting something from the outside is much lower.
Maintenance, consisting in cleaning from dirt, drying and removing water, salt that got into the bushings, sea water, fine dust or river silt after a difficult bike ride. It is desirable to carry out such an operation as soon as possible after returning. It is not necessary to remove the cassette. Already, pulling out the axle, it becomes clear how serious the situation is. Changing the oil in the support bearings is not difficult at all; for this, only cone wrenches are needed from the entire long list of tools.
Preventive bulkhead with partial or complete disassembly all components, surface cleaning, removal of all contaminants, exhaustion, oil change and thorough inspection. This is best done at the end of the season before the winter storage of your favorite horse. If you ride a lot and in winter too, then before winter season you can clog more "winter" grease, and at the end of winter - completely sort out the nodes where water or salt from the streets could get. After all, during winter skiing, snow is clogged into the bikes decently. And lubricate the bushing with a lighter and more salable summer grease.
Bushing design
Bushings consist of very standard parts - balls, which are abundant in any industrial bearings. If necessary, you can get any bearing with balls that are suitable or even similar in diameter, remove them from there and put them in the sleeve.By the way, if the bushing starts to make noise, it makes sense to replace the old balls with new ones, without surface defects; but you do not have to look for suitable bearings in their entirety, as is the case with bushings on industrial bearings. Corrosion is ruthless to any steel.
General diagram of the hub from the Shimano manual. HVZ bushings are almost identical. Differences in anthers and seals.
Required Tool
From the tool you will need
- a pair of special thin "cone" keys 13-14-15-6 and 13-14-15-17, made of strong tool steel;
- a special key-whip with a piece of chain for fixing the cassette;
- cassette remover (sleeve with ribs);
- 24 open-end wrench, which can be replaced with anything;
- hexagon 1.5mm (for complete disassembly or pulling the cassette);
- hexagon 10mm (for removing the freewheel drum);
- an ordinary bicycle universal key HVZ, in which you need a convenient end between the horns 10 and 12 as a drum puller
- medical tweezers (remove the balls from kerosene and put them in a holder)
- an old toothbrush (more convenient to wash);
- pliers (pliers) of medium size.
"Whip" - they keep the cassette from scrolling during dismantling:
By the way, this is also a pedal open-end wrench "for 15".
Cassette remover (black) and the key with which it is twisted:
Usual "family" bicycle key Ukraine, produced by KhVZ. Its left end part is useful as a drum puller.
Cone (sleeve) wrenches are indispensable for adjusting cones and locking.
Hexagons. A large one is useful for removing the drum, a small one for disassembling and assembling the cassette.
Removing the cassette
Remove the eccentric axle. Pay attention to exactly how the springs stood - they should, as it were, be directed with the narrower end inward, with the wide ends towards the nut and eccentric, as in the diagram, item 1 from the Shimano manual. Disassembly should begin with the dismantling of the cassette. Firstly, it is dirty and large, and it also does not interfere with cleaning and putting in order. Then, you need to make sure that there is no wear on the drum housing. If the drum holding the cassette gears is worn out, then the drum (freehub) must be replaced, but, fortunately, this happens extremely rarely.
Insert the cassette remover into the smallest sprocket in the appropriate hole. With your left hand, put the holding key-puller with the chain on the cassette, right hand, conveniently grabbing the key at 24, turn the nut holding the cassette by the puller. We unscrew the nut from the drum body, the thread is right (standard). It may take a lot of effort.
Then carefully remove the cassette. It will consist of several parts: the main one with 5-7 largest gears fastened together and separately the smallest and 2-3 smaller ones, possibly through spacers (rings). All this must be remembered or sketched (photographed), if you are not sure of yourself.
The result should be something like this:
If the dirt stuck tightly, the cassette can be left in an airtight container with kerosene for half an hour so that the dirt and oil acidify. Then, having cleaned with a brush and wiped with a rag, it is necessary to carefully examine it for deformation of the teeth and wear (chipping).
In the photo - an almost new cassette, which has traveled 1000 km, but along a mountainous terrain and with a good load - on 4-7, the most frequently used and most loaded stars, jamming of the edges of the teeth is noticeable. Especially got the stars 19 and 23.
"Cracking" and burrs impair shifting; changes in tooth profile can cause a chain slip effect. The reason for the deformations is simple - riding with a stretched old chain on a new cassette. If the chain were new and the link length would be normal, the cassette wear would be less pronounced, more uniform and not at all so pronounced.
The gouges can be carefully cut off with a thin file, but only "extra sagging" in thickness, without touching the tooth profile itself. This will slightly improve the switching, but, unfortunately, will not affect the remaining resource in any way. A photo of the cassette processed in this way is at the end of the article.
Pay attention to the reliability of fastening the cassette unit. Some models of cassettes are riveted, some are collapsible. Collapsible can spontaneously unscrew. In the photo - a hexagon screw that fastens the entire cassette and the 1.5 hex key itself, with which to twist it.
You can carefully disassemble the cassette, then it is much more convenient to clean, inspect and correct it. Do not confuse only the parts in the order of assembly. With age, all elements of the mechanisms are rolled to each other and become individual. Therefore, it is very undesirable to change them in places unnecessarily. Also note the positioning tooth (it is next to the "M" in the photo), it is slightly different in width from the others. You can just assemble the cassette on the drum, it's more difficult to confuse something.
Bushing disassembly
You should prepare in advance kerosene 100-500 ml., A suitable container for washing parts, rags and toilet paper. As a container, I use a 180 ml herring jar, 140 mm in diameter (it fits very comfortably bicycle chain, but not about that now). Even for soaking parts, a sealed "jar for analyzes" of 100 ml is well suited, which is sold in any pharmacy for 20-30 rubles. You will also need a lube and a 20 ml syringe. for accurate application. It is possible and carelessly, with a screwdriver to smear, as you like. There are a great many lubricants: from foreign lithium types MOBIL Mobigrease XHP222, Kharkov XADO with revisions to the banal CIATIM-221 (history and classification of LITOL-CIATIM lubricants), which, by the way, is also lithium. Who loves their bushings and who likes what. Only grease is not needed - it absorbs water and everything under it will rust.
A little about cone keys. The peculiarity of these keys is the thickness of only 2.5mm. They are necessary for unlocking the bearing cones during disassembly, where a standard open-end wrench will not fit due to the thickness, and during assembly - for fine adjustment and locking of the same cones. These keys are sold and are inexpensive, about 200 rubles, and will come in handy more than once. Nothing else is needed for the front hub.
Carefully unlock the cones, disassemble, wipe old grease, lay out in order of disassembly and remember how it was. The diagram from the Shimano manual will help you figure it out.
Please note that according to the manual, the freewheel drum (freehub) is supposed to be non-separable. So it is, they offer to change it as a spare part, "fine work". But this will not stop us - we will also disassemble and clean it, replace the lubricant and inhale a little freshness.
The last pictures for those who get confused and a little more about wear.
This is what the rear axle of a 10 year old Shimano Deore hub from 2003 looks like as if it were inside the hub.
Number of balls in the Shimano Deore REAR hub: 9 pcs. 6.35 mm (1/4") diameter on each side.
Number of balls in the FRONT hub Shimano Deore: 10 pcs. 4.75mm (3/16") diameter on each side.
Attention should be paid to the quality of the rolling surface of the support bearings. The surface must be smooth and shiny, free from pitting, cavities or corrosion. A knurled track in the form of staining, as in the photo, is allowed if it is not felt to the touch with a fingernail. There should be no ball prints - if there are, then it was swipe on a wheel with cone deformation; in this case, the wheel will never be able to adjust for optimal rolling and minimal play and the hub will constantly rattle and "there is dirt" until it frays itself.
You should also wash in kerosene, wipe and carefully examine the balls themselves. They should also be smooth, shiny and absolutely round. If the balls have traces of any corrosion or mechanical damage, then it is better to replace them. It is necessary to change all the balls at once - it is very important that all the balls in one bearing are of the same diameter; if any ball is larger than the other, the entire load will fall on it, and a point load will quickly destroy both the ball and the rolling track.
High-end bushings are made from very strong alloys; problems arise only due to salt, dust, dirt, clay or sand particles that have got in, and sometimes also due to improperly selected or simply missing lubricant. As a rule, after proper care, they again work like new for more than one cycle.
Drum disassembly (freehub)
To remove the drum from the hub body, use a 10 hex wrench (14 for Shimano XT/XTR hubs). The thread is normal (right). In addition, in order to remove the drum, it is possible only from the spoked wheel, because otherwise it is very problematic to hold the hub. It is necessary to rest and, holding the wheel, turn the hexagon according to the right-hand thread rule, unscrew the sleeve towards ourselves. It may take a lot of effort.
After the retaining sleeve is unscrewed with a hexagon, the drum will be removed and a thin rubber gland will be found on the reverse side. It can be pryed off with tweezers or a sharp object and carefully removed, then the balls of the lower thrust bearing will be visible.
ATTENTION! DRUM BEARING THREAD - LEFT! Be careful with dogs and springs - they tend to scatter in different sides during hasty disassembly.
The number of balls in the Shimano Deore drum: outer part - 25 pcs. And inner part- 25 pcs. diameter 3.17mm (1/8").
Remember, the balls will fall out as soon as the halves of the body move relative to each other, so be careful also over the cuvette so that they spill out into a limited container and do not have to be searched all over the floor.
The balls should be thoroughly washed (perhaps soaked in kerosene overnight if not washed immediately) and inspected for defects. The photo shows that many balls have "pockets" and cavities. Apparently from the factory. This probably explains the unpleasant noise and rumble of the bushing at idle. No artifacts were noticed on the rolling tracks.
There are spacer rings in the drum that regulate the play. In the photo - a thick spacer ring 2.35mm and three thin adjusters: one 0.15mm and two 0.10mm each. If the drum is a little loose, and it often happens that at the factory they prefer to put on an extra ring to simplify the adjustment, then one ring can be removed. The drum should not backlash, "overwrite" - too.
Drum assembly (freehub)
After cleaning and drying, we collect everything back. The assembly is simple, but the assembly order must be followed correctly. Lubricate in moderation, not too much and not too 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 on the grease. Holds confidently, checked.
In the photo, the balls are stuck INCORRECTLY, it was necessary to sculpt them around the INNER DRUM, then installing the part with the dogs inside the freehub drum will not be difficult.
Then, with tweezers, the balls are carefully placed on the other side. Then spacer rings are placed on top, first thin, then thick, then a slotted ring (thrust bearing) is screwed on - LEFT thread!
We install the freehub on the sleeve, do not forget to check if the rubber seal is in place with inside and if they forgot the puck; tighten with a hex well. Freehub should spin freely without jamming and backlash; in the opposite direction to be clearly fixed.
Axis setting
When installing the axle, you should 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. Immediately stretch a pair of cone (9) - nut (3) with keys, locking. Then put grease into the bushing on both sides, smooth 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 backlashes and then don't forget to lock the second pair of cones.
Another assembly drawing:
As a result, the protrusions of the axle on both sides should be almost the same and less than the thickness of the frame feather (6mm).
Anthers are conveniently seated with a cassette remover - just the right size; fits into place evenly and accurately.
Cassette tooth reshaping
Optional procedure. The gouges from the stretched chain, as mentioned earlier, can be carefully cut off with a thin diamond file, leveling the "excess sagging" in thickness, but without touching the tooth profile itself! The teeth are all different, with different bevels and approaches, some are just slightly turned 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 the shifting, but, unfortunately, will not affect the remaining resource in any way. Photo of the raw and processed SRAM PG-970 cassette in this way:
The recommendation applies to the high-end SRAM 970 and SRAM 990 PowerGlide II cassettes (they 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-plated Shimano Deore, Road 105, SRAM PG-950, 980 and lower class cassettes. The basis of the star in these cassettes is mild steel, which is easily deformed by itself, and peeling off the chrome coating 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 a class higher.
I also want to note that the deformation of the teeth is almost always the result of riding a stretched chain out of ignorance or "out of conscious economy." Take care of the chain, timely measure its length (or elongation) in any way possible, and this will significantly extend the life of both the cassette and the front system.
Bushings of this type were installed on almost all Soviet single-speed bicycles, as well as on classic motorbikes, up to and including the MV-18. In the construction of a homemade motorbike, old ones are also often used. bicycle wheels, and even in the restoration of a motorbike like Gauja or B-902, one cannot do without a bulkhead and normal operation of such a bushing! But often for hole drivers these bushings remain a kind of “black box”, and all care ends with stuffing oil into the bushing, which, by the way, only harms its normal operation. And then the result - the brake does not work when the pedals are turned back, or it works poorly, and the wheel dangles, plays ...
That is why this article is being written, since there is a camera, the Internet and the need to assemble a well-functioning sleeve of this type.
This type, I must say, is very old, the design began to be widely used on bicycles back in the 1900s, and the design of the bushings produced in the USSR has hardly changed at all since the late 1950s, all parts of the bushings produced by different factories are absolutely interchangeable, the differences are only small, like the hallmarks of the factory. Now such bushings do not seem to be produced - even a reserve in Belarus - the Minsk plant on its own road bikes puts bushings of a slightly different type, I suspect that they are Chinese - where the metal is used very often worse, and the design is flimsier ...
Very old bushings differed in the fastening of the sprocket - it was threaded and locked with a nut like on a carriage, only with a left-hand thread. Such stars were usually 20 teeth. Also, on such bushings, the brake drum had halves of a smaller diameter, connected not by a steel spring, but by a brass lining over the entire surface of the drum, with a check mark cutout. Bearing cages also had a different look. All parts are interchangeable with modern ones.
Device
So, about the design of the sleeve with a rough tongue, not a poster, but instructions:
Inside the housing 3 bushings are ball bearings, a freewheel mechanism and a brake mechanism.
The freewheel mechanism or drive mechanism is located on the right side of the hub.
A leading cone 14 is placed on the axis 17, which has a ball track and five shaped sockets, the bottom parts of which are made in a spiral. Five leading rollers 19 can freely roll within the sockets, the axes of which are parallel to the axis of the sleeve. A cup 10 with five slots is put on top of the driving cone with rollers, from which the driving rollers protrude slightly above its cylindrical surface. On the left side of the cup there are two end protrusions (cams) with a helical surface that are in contact with similar protrusions of the brake cone 9. On the ball track of the leading cone, eleven balls are placed in the separator, forming, together with the leading cone and the housing, on the inner surface of which there is a ball track, right freewheel bearing.
On the inner ball track of the leading cone, there are seven balls in the separator, with the right cone 16, screwed onto the axle to failure, the stroke bearing, protected by a dust fuse 15.
Driven sprocket 12 is splined on the driving cone 14 on its right side outside the bushing. chain drive, fixed with a thrust ring 13. The left end of the axis 17 is screwed into the left cone 2, which has a ball track, on which eleven balls are also located in the separator. They, together with the cone and the sleeve housing, form the left bearing. The bearing dust guard is pressed onto the left cone. All bearing balls rear hub have a diameter of 6 mm.
The brake mechanism of the hub consists of a brake drum 4 and a brake cone 9, located together with the parts located on it in the right part of the brake drum 4. The left side of the brake drum is put on the conical part of the left cone and is protected from turning by the antennae on its end, which are included in special grooves on the left cone.
The left cone always remains stationary relative to the bicycle frame, since it is rigidly connected to the chain fork of the frame by the brake lever 21 and the clamp 22 located on the left side of the bushing.
The brake drum consists of two separate longitudinal halves, fastened with an annular band spring 5. On the cylindrical part of the brake cone 9 there are two flats on which two brake rollers 8 are placed, held by a brass separator 20. Two brass separator tongues slightly bent outward slide with some friction along inner corrugated surface of the brake drum. Washer 7 and thrust ring 6 serve to hold the separator on the brake cone. The bushing mechanisms work as follows.
When the driven sprocket is rotated relative to the sleeve body clockwise at the beginning of the pedal stroke, the driving cone associated with the sprocket will begin to rotate relative to the cup 10. The cup at the beginning of the cone rotation is somewhat late, since its end protrusions meet resistance from the protrusions of the brake cone 9 rotating inside brake drum with some friction. When the cone is rotated relative to the cup by about 20 ", the drive rollers 19, held by the slots of the cup, under the influence of the spiral surfaces of the sockets of the driving cone, will move outward and wedged between the inner cylindrical surface of the body and the sockets of the driving cone. Significant friction forces arise at the points of contact of the rollers with the inner surface of the body. , firmly coupling the body with the drive cone.Now the hub body rotates with the sprocket as a whole and through the spokes the torque is transmitted to the wheel rim.During the working stroke, the rotation of the wheel is carried out on two bearings: the left bearing and the small bearing of the working stroke.The cup during rotation entrains behind it is the brake cone, which rotates inside the brake drum during the entire period of the stroke.
When you stop pedaling, the bike continues to move but inertia. At this moment, the sleeve body during its rotation overtakes the stopped driving cone 14 with the rollers 19 sitting in its sockets. The rollers, slightly turning around their own axes, wedged and freely roll into the deeper places of the spiral sockets of the cone. The cone and the sleeve body are separated. The wheel now rotates on two ball bearings in the hub housing: the left and right freewheel bearings.
Travel bearing not working. The bike is free to move.
If the bicycle needs to be stopped, the pedals are turned in the opposite direction, against the motion of the bicycle. In this case, braking is carried out. The driving cone 14 rotates against the wheel and, by means of the rollers 19 in its sockets, drags the cup 10 along with it. The cup, resting with its end screw ledges against the brake cone 9, will begin to turn it inside the brake drum 4. into the longitudinal grooves of the corrugated inner surface of the brake drum, do not allow the brake cone to turn further. From this moment, the screw protrusions of the cup 10, interacting with the brake cone, will begin to push it inside the brake drum 4. Under the action of the brake cone, the drum shifts slightly to the left and moves with its left side onto the conical "part of the fixed left cone 2. With further pressing of the brake cone into the brake drum the latter moves apart. Its halves, connected by an elastic band spring 5, diverge and, pressing against the inner surface of the sleeve body, create friction forces that slow down the wheel. Rotation of the drum together with the sleeve body is excluded, since the antennae bent inward on the left side of the drum, entering the grooves fixed left cone 2, prevent turning.The braking moment is perceived by the left cone through the brake lever connected to the bicycle frame.
Taken from here: http://www.velonet.narod.ru/masterskaya/baza/ztv/ztv.html
Still not clear? No wonder I didn't understand either...
Device in pictures
Then here is what the instruction (for the Riga bicycle of the 1950s) writes about her work, here they tried to visually draw:
Still not clear? Then pick up the wheel, the keys - and read on!
How to disassemble
So, it's time to disassemble the bushing.
Let's take it off the frame first. As a rule, the threads are not broken, but people with long keys and strong arms nevertheless, there are, so first we completely unscrew the fastening nut on one side, then on the other.
Unscrewing, hold, if necessary, by the square tip of the axis. It is best to fix the square with a special hole in the "family" key, you can - with a clamp or an adjustable wrench. Pliers - it's not worth it, it's easy to break the edges.
Then we unscrew the flat nut with slots, and remove the washer:
On my copy, the nut is still decent, made before the innovators began their wrecking activities, but already in the 60s these nuts began to be stamped from some kind of soft metal and too flat, so very rarely they are satisfactory even new. In most cases, the thread on it is torn off.
This nut is important, without it it will self tighten and/or self loosen.
Also important is the washer, which is fixed from turning in the groove on the axle, do not throw it away, if the protrusion is torn off, it would be necessary to replace it.
The brakes are not released if the conical surfaces are worn out (such as a ramp), or they are not made to size, or the play in the wheel, as an option, the bushing is incorrectly assembled, on the wrong side.
That's it, congratulations, you can take out the most terrible mechanism, nothing should fall apart! Scattering ball bearing - ruthlessly change. Its price is low, but it will obviously become better. At least it's easier to assemble...
The brake drum, together with the fixing rollers and the release part, is simply removed from the axle. Axle - removed as well, without delay.
The right (small) cone also walks on the bearing, if there is a suspicion that the balls in it are not very good, we remove the metal boot and get to the balls in the cage:
Carefully! The anther is easily damaged, it is possible to pick up a similar Chinese one, but it is difficult. So - first wash thoroughly, soak in HP, then gently pull from different sides.
The mechanism for fixing the working stroke with large rollers remains unassembled:
By prying a thin spring ring, we can clean out deposits from here:
Now you can remove, check and clean the large right bearing:
If desired, you can also remove the asterisk by prying a thick spring ring with a thin screwdriver. But remember that putting it back on is a little more difficult than taking it off...
That's all - you can wash the parts in kerosene, check.
Separately, taking an expandable tomose drum, and inserting a piece with brass antennae and small rollers into it, try how it works by twisting it in different directions by the protruding gentle teeth. You can also see how the large left cone enters the drum in grooves - this is done in order to support it during braking with the same lever that stands in the grooves of the left large cone. Otherwise, it would have been spinning inside ...
If now, with clean parts in your hands, you return to the first post and color pictures, it will be easier to understand the device and the principle of operation.
The key - when you turn in the right direction - the rollers (both large and small) move forward.
Large, curved pedals forward - pressed against the outer wall of the sleeve, and you can pedal and ride. We remove the effort - the rollers return, "enter", and slide - this is a free move.
We turn the pedals back - flat teeth begin to press in the part with brass antennae, small rollers on it move forward, press against the grooves inside the brake drum. The drum is unclenched (it consists of 2 halves) - we brake, by rubbing against the outer wall of the sleeve. Again - we remove the effort, and the rollers return.
That's why - lubricate the sleeve only with liquid oil - the rollers should walk very easily! How to lubricate it without disassembling and without washing dust and sand inside at the same time, when the saboteurs removed the grease fitting from the structure, is a mystery. But it’s cheaper, more technologically advanced in production, and the rationale has been introduced ...
We grease with grease only directly on the bearing balls, and without fanaticism - there is nothing to do further inside the LITOL bushing.
Dismantled? Now let's rinse (it's most convenient for me with a small brush in a bath with diesel fuel, the details in the photo above were not washed due to work in the kitchen, I just wiped it with a cloth, I'll wash it later) and read on!
Detection
The bushing I got from the Riga plant in 1958 had several typical malfunctions, so let's consider it as an example.
The chrome is very well preserved, the brand, apparently, was not deeply knocked out at the factory, but parts of the Latin letters RVZ and the star are visible. The same stamps are on the native hubs of the Gauja motorbike.
This, too, is the design of the oil dish, characteristic of the Riga plant. Then they (oilers) were “rationalized” as an “extra” part, but until the beginning of the 70s they were still found on new bikes.
There are signs of wear inside - the bushing worked, it was braked quite a lot, the pressed brake drum made grooves, but the wear is far from critical - this one still has to ride and ride! It is important to note that the grooves along which the bearing balls roll in the cage are even, without cavities, dimples, ulcerations. Not perfect, of course, but good.
But the grooves of the counterpart - the cone of the left side - turned out to be damaged, as well as the bearing balls themselves.
Therefore, I am looking for from other bushings bought at a flea market and collected from landfills - a whole cone with fairly even grooves:
On the right side, the cone of the working stroke, which stands on the axis, turned out to be normal, as well as the axis itself, even, not bent (best seen in rotation, by inserting, say, into a drill) and the thread on it was not broken anywhere:
But the balls of the bearing of the working stroke - alas, with caverns, not quite “dead”, but also not serviceable:
On the bottom ball, dots-dents are visible. In general, in the case of Soviet bicycle hubs, the version of exclusively good quality bearings manufactured in the USSR are not confirmed, the balls and tracks of the cones, even of the “old years”, turn out to be damaged.
This is not very scary - the design and size of the bushing is designed for tolerances and metal of the early 20th century, it will work somehow, it is difficult to “kill” this bushing completely, but it will not only crunch or spin hard, but it will also be impossible to adjust - either the wheel dangles, or slows down even more and collapses further and further.
With a normal bulkhead, we replace the defective one. In bicycle shops in Riga, such bearings in cages are not uncommon, they cost a little. We change!
Next is the detail that fixes the brake drum. The one I received is in good condition. The teeth and a kind of gentle “ramp” are whole, even, without chips, as it happens. The brass clip is even, not too much bent outward, the rollers are intact, they go well.
The trouble with such details recent years release - a tube with flat antennae comes across from plastic brass, and not from springy, respectively - the antennae bend down and do not work. As a result, there is a delay in the application of the brake.
The antennae should be slightly bent, easy to slide over the drum - then it works fine. If you bend it too much, it will crack for a while, and the brass will wear off. It will not be bent - the brake will start to scroll.
It is the condition of this part that is often the reason that the bushing "does not slow down." The fact is that the rollers in it should freely, easily, without the slightest delay, spin and walk, protrude when clamped - if there is a generous amount of grease, grease, and even dust and metal particles are added - the rollers will not come out, and there are “scrolls » Pedal back. That is why - such bushings are lubricated only with liquid oil, they cannot be clogged with anything like LITOL.
Also, for the normal operation of the brake, it is important that the counterpart for the rollers - the expanding brake drum - is not excessively worn out, so that the rollers fall into such grooves, waves, and do not slide along a flat, worn surface.
I repeat, wear is visible here - but not critical, grooves remain on the outside, and slots for the rollers on the inside. This drum - hardened, expanding, is made by splitting the workpiece in two, so if you disassemble it, then two halves are suitable only from one, you cannot take from different ones. What else could be corrupted?
Well, with an asterisk it is clear - the teeth themselves, along which the chain runs, must be uniform, otherwise the new chain on them will crunch and wear out very quickly. Here - everything is in order. Noted - the grooves for the bearings are also alive.
This asterisk from the Riga factory has oval slots, but later they stopped making them. They are needed to make it easier to change the spokes - it is not necessary to remove the asterisk for this.
Three slots are visible on the sleeve, into which the protrusions of the asterisk enter - these protrusions are worn out, the asterisk dangles from this. Unpleasant, but tolerable. The spring ring holding the sprocket in place must not be excessively rusty, intact, not bent, and lie completely in the groove.
On the reverse side you can see the dust ring, which stands in front of the asterisk. The previous owners could have lost it, so it's better to return it so that the dirt gets into the bearings less. Bearing grooves, traditionally, are checked for evenness, grooves for large rollers - so that they do not chip.
Here's the damaged part for a replacement. On the grooves for the bearing balls, the caverns are clearly visible, it will not work normally. In addition, the sprocket dangled, the protrusions securing it were noticeably worn out, and there was no sealing dust ring:
The choice of bearings must be approached with caution, remake of unknown origin may be of poor quality. It is also possible to dismantle a closed industrial bearing with balls of the appropriate diameter, and change only the balls. When changing only balls, it is recommended to measure them with a micrometer, to reject those that stand out in size.
Hub Assembly
It is assembled, as they say, "in the reverse order", but just in case, photos and explanations:
First, on the axis, on the side on which the square end, we screw the cone, until it stops, to the end of the thread, even if just with fingers. You can tighten it a bit, without fanaticism. Then we put anther on the cone. The boot can also be inserted into the bushing with an asterisk - it depends on what it holds on better.
We put on a bearing lubricated with grease (I have grease with molybdenum disulfide, which is why it is blackish). I remind you that the rest of the parts, except for the bearings, do not need to be lubricated with grease! Then we will pour a little bit of mineral oil on them.
Don't forget about the figured puck:
Then, holding the square tip, we twist the large cone, twisting it by the jet lever (this is that shiny thing that is attached to the frame with a clamp). It is necessary not to twist it to the end, but so that it is slightly loosened, otherwise it will be too tight at the final tightening. At this stage, you can insert it into the frame and already grab the horse with the square, already with the nut that fastens the wheel to the frame.
Everything, we wind it up and again, without fanaticism, we put the locking nut (I remind you that it is important to be whole and hefty, otherwise the whole structure will self-twist and self-unwind, and slow down or hang out badly):
Then we fasten the reactive lever with a clamp (I recommend placing an elastic band or cardboard under it so that the lever cannot go back and forth, in order to counteract self-unwinding) and tighten the wheel nuts. If, after tightening the nuts, it became worse to turn, it means that there were not enough loosenings during assembly, or the washer turned. We loosen both fastening nuts, and twisting by the square tail, without removing the jet lever from the clamp, you can release the cones a little. Then tighten the nuts again, including the locking one. Spinning should not noticeably worse than the front.
That's it, congratulations, now you can pump up the wheel and go!
Especially for motorcyclists - I remind you how the motor sprocket is put on the wheel:
Smooth roads and reliable engine operation!
And finally, for general development and information...
Other designs of bicycle single speed hubs
A normally assembled bushing of a schoolboy walks for several years without problems, or until someone gets into it. There is nothing special to wear out in it. The whole trick is in the correct installation of parts 20-22. People assemble it haphazardly (I have seen it many times), and then they are surprised and say - G. The problem is also due to the fact that after incorrect assembly, people are sometimes simply too lazy to straighten bent parts or replace a washer with a broken antennae.
And here is another interesting type of sleeve, "Go" (Eadie). Here are photos of the "Go" bushing. This hub is from the pre-war (1940) MD-1 bicycle, produced by the Moscow Bicycle Plant.
The appearance of the assembled bushing. I was surprised by the size of the wheel nuts: their turnkey size is only 14mm, despite the fact that the thread on the axle is the same as on the Torpedo bushing, i.e. M10x1.
All removable parts are removed from the hub body:
They are on the axis:
A screw pair is visible, due to which the freewheel mechanism works (in the absence of rotation of the driven sprocket), the clutch mechanism (when the driven sprocket rotates clockwise) and the braking mechanism (when the driven sprocket rotates counterclockwise).
The principle of operation of the brake mechanism:
Disinhibited
Inhibited
Views of the empty sleeve housing on the right:
(convenient slots for changing spokes without dismantling the driven sprocket!) and on the left:
You can see the mating part of the clutch mechanism.
One of the bushing bearings is loose:
True, there are not enough balls here, probably some of the balls are lost.
A good competitor to the Torpedo bushing - fewer parts, simpler, more rubbing surfaces.
The minuses are heavier, the knitting needles are different.
Sergey Sbech
Discussion of the article "Bicycle bushings"
Thank you!
Excellent, detailed and well written article!
In Tambov, spare parts for "Torpedo" bushings are not a problem. Dmitriy
05/19/2015 at 08.14
Hello! The question is not simple.
Please tell me or point/direct me, if anyone knows a source where you can find the standard sizes (more - inner and outer radii of cups and axles and cones and other parts) for this bushing.
I'm asking for answers. Any.
Be it an expensive sports bike or a simple teenage bike. The reeling, and hence the coefficient, depends very significantly on their quality. useful action bicycle, which is important - after all, when riding a biker, he spends not just anything, but his own forces. Not without reason, rolling bearings first appeared in large numbers on bicycles, and later spread to many other machines and mechanisms.
General design features
Bushings designed for different bicycles differ in such parameters as the presence of additional devices, strength and type of protection from external influences. Accordingly, both weight and price differ significantly. And if the hubs of a mountain and road bike have approximately the same structure, then the hubs with built-in brakes already differ quite significantly, and the hubs with planetary gear shifting are radically different.
The simplest design is at the front wheel hub of a conventional bicycle. Cylindrical body, on the ends of which there are flanges with holes for fastening the spokes. Inside the housing there is an axle and bearing assemblies, covered with anthers. The device of the rear hub of any bicycle is noticeably more complicated.
The rear hubs of multi-speed bicycles, apart from planetary ones, can be of two types. Outdated threaded bushings, where a ratchet, i.e. a block of stars together with a ratchet mechanism, is screwed onto a bushing or modern - drum ( Freehub), where the ratchet is part of the hub, and the cassette is just a set of stars. In addition to traditional ratchet hubs, there are also so-called "roller" hubs that are much better able to withstand the shock loads of freewheels and star gears, such as in the DT Hügi.
The bodies of modern bushings can be cast, turned or stamped, made of aluminum alloys and, in part, titanium alloys. Turned and stamped aluminum bushings are now the most common.
Hubs designed for radial spoke wheels have hardened flanges to withstand radial loads. Bushing axles can be steel, aluminum or titanium. Bicycles designed for extreme disciplines have front hubs with 20 mm axles and rear hubs with 12 mm axles.
bushings mountain bikes are divided into “normal” and “disc”, i.e., designed for installation of disc brake rotors on them. Two incompatible rotor mounting standards are now common: ISO on six bolts and slotted with a retaining ring, the so-called Shimano Center Lock.
The wheel can be mounted on a frame or fork either with nuts - only on inexpensive bicycles, or using an eccentric mechanism ( quick release). The convenience of using an eccentric coupler lies in the ability to quickly remove and install the wheel without the use of tools. The 20mm axles for the DH are secured with a cam and a fork leg bolt.
Modern mid-level mountain bike hubs have a double contact seal. Expensive hubs such as DT Swiss and road bike hubs use a labyrinth seal, which creates less resistance to wheel rotation than a contact seal, but protects against dirt and water somewhat worse.
Bearing types
By now, bushings with angular contact conical rolling bearings. For example, all Shimano hubs use these bearings. Bearings consist of an outer and inner race, a set of balls, and sometimes a cage.The inner race is a cone screwed onto the hub axle, while the outer race is pressed into the hub body.
The main advantages of bearings of this type - maintainability And possibility of adjustment as it wears out. Of the shortcomings - assembly complexity(many details) and need for adjustment.
Another type of bearing previously only found in road bike hubs is radial cage (industrial) bearings. Now they have spread to mountain bike hubs.
The advantages include lower friction losses, ease of assembly bushings, no need for adjustment. Taking into account the easy replacement of the bearing, the resource of the bushing increases many times over. But radial bearings poorly tolerate axial loads, sometimes occurring in bicycle wheels. Interesting feature some of these high-end bushings is that they can be disassembled with only one hex wrench.
About changing spokes
For a front hub that does not have a disc brake, replacing broken spokes is no problem, since the spoke can be easily inserted into the hub flange from the side. But this option is of little use if a hub with a disc brake or a rear hub is considered. To install the spokes into the flange, you will have to remove the brake rotor and cassette, which greatly complicates the work and requires the use of special tools.
Mavic uses segmented flange hubs for special straight spokes. Replacing a spoke in a wheel assembled on such bushings is very simple. Shimano went the other way with new wafer hubs. DDH(directional design hub). Knitting needles of a traditional shape (with a bent, riveted head) are inserted into special slots on the body.
The only serious drawback is that during operation, the slots on the body become clogged with dirt, and it becomes very problematic to remove the spokes from the wheel. Apparently, this was the reason that DDH bushings did not become widespread.
The second obvious reason is that the company has moved into the production of whole wheels (wheelsets). Their hallmarks began to use a small number of spokes placed with nipples to the hub (stepped flanges) with fastening not in the center of the rim, as is usually the case, but on its sides.
Manufacturers
Most widespread in this moment Got Shimano hubs. In the eyes of many cyclists, Deore LX hubs ($15 and $30 front and rear) weighing 205g and 426g. - the best Shimano hubs in terms of price / quality for a mid-range bike. For very inexpensive bikes, the choice of Shimano Alivio hubs ($10 and $15 respectively) can be considered acceptable.
To bushings high level Shimano XTR hubs can also be attributed. Their cost can range from $100 to $300. And the weight of the same American Classic non-disc hubs is only 120 and 225 g!
Results
In conclusion, it is worth mentioning that the quality of the bushing depends very much on the type of bearings, the quality of their processing, as well as the quality of the seals. The softness and ease of rotation of the bearings is determined by the accuracy of the manufacture of parts, the type of polishing treadmills and bearing balls, their surface hardening and compliance with tolerances. But remember that no matter how high the bushings on your bike are, nevertheless, you should not dip them into the water once again, this will not do any good.
Andrey Grigoriev
What is the most important part of a bike? Of course it's a wheel. It does not matter what type of bike we are talking about, what price category it is in - it is simply impossible to imagine any of them without wheels. And what is directly responsible for the rotation of the wheels? Quite right, that's exactly bushings. The better they are - the better the bike will have "rolling", which in turn affects its efficiency. Also, the bushings are responsible for the correct and uniform distribution of radial and circular loads, uniform rotation of the wheel and sometimes - stopping the bike or switching gears. Since this element is obviously important, let's talk about it in more detail.
How bicycle hubs are arranged:
The most important things in the life of a bicycle hub are rolling bearings - these are ball parts used to transfer torque from the axle to the body of the part and, as a result, rotate the wheels. To date, there are three most common types of rolling bearings used in the bicycle industry: ball bearing, industrial or closed, and cage.
The front hub looks like this:
1 - locknut;
2, 8 - cones;
3, 7 - flanges;
4 - a set of bearing balls;
5 - body;
9 - washer;
10 - nut or eccentric;
It should be noted that in "bicycle horses" of all types and varieties, the bushings are similar in structure. Naturally, the differences may lie in the material used in their production, the degree of protection, weight, safety margin, running life and durability.
If we compare the front and rear hubs, then they are simpler in design, because there is less dynamic load on them, like on the entire front of the bike. Another complexity of the rear mechanism comes down to the fact that there is the possibility of free play, this does not apply to fix bikes. This confirms the fact that the front bushings are less whimsical in repair and periodic maintenance.
Now let's take a closer look at different types bushings and their special device. If we talk about the type of production, then they can be stamped, cast or point. Stamped and dotted completed most modern bicycles. Point marks are highlighted as a spiral on the surface with outside. As for cast ones, they are put on models for beginners, on teenage and children's models, because they are less durable and weigh more.
For the production of bushing bodies, the following materials are used: titanium and aluminum - for point and cast, steel - for stamped. In addition, there are bushings whose bodies are made of carbon - this makes the bike much lighter, because the weight of the carbon bushing (which is not inferior in strength to others) is 49 grams, while the aluminum ones weigh 245 grams.
Hub axles are mainly made from aluminum and steel, sometimes also from titanium. They may have different diameters.
Let's highlight the most common axle sizes:
Axle standards table for front hubs
Table of axle standards for rear hubs
The diameter of the axis of any bushing determines such connection characteristics as rigidity and strength: the larger it is, the greater the parameters can be provided. This affects the total weight at the same time. In addition, removing a wheel with such an axle requires a lot of time and effort.
Often, the rear hubs are asymmetrical to accommodate cassettes. For this reason, the right flange is located closer to the middle and its spokes are shorter on the right side by several millimeters. This fact must be taken into account when lacing the wheel.
Now let's focus on bearings - an important part of the bushings. Now it is more common to find bushings with bulk bearings, and less often with cage bearings. Their distribution is explained by a high running resource and ease of production, and as they wear out, they are easy to adjust and sort out. A well-known manufacturer in the bike industry like Shimano only uses bushings that have loose bearings.
Bushings having radial industrial bearings are less common. Compared to standard ball bearing systems, they do not need to be dismantled and are very easy to install. Such bearings can greatly increase the running life of the part, have better dust and moisture protection due to higher efficiency and lower rolling resistance. However, this greatly affects the weight of the part, since the weight of closed systems is greater, as is the hub housing for them. This type is found in those bicycles to a greater extent that are used in extreme sports sports.
Varieties of rear bushings and their differences
As already mentioned above - on the rear wheels are more complex axial than on the front. In addition, the bushings have special inserts for ratchet, cassette and brake discs. On planetary bikes, the rear hubs are gear systems that are comparable in complexity to a car's gearbox. On today's city bikes and SSSR bikes (classic), the rear hubs still have brakes.
The rear hub looks like this:
1 - eccentric;
2 - assembly of parts on the hub axis;
3, 15 - locknuts;
4, 5, 7, 13, 14 - washers;
8, 12 - sealing rings;
9, 11 - bearing cones;
10 - axis;
16 - anther;
17 - hollow bolt for fastening the bushing drum to the body;
18 - a set of bearing balls;
19 - drum ("nut");
20 - washer;
Types of rear bike hubs by structure:
a classic version with a ratchet or cassette mount. Many models still have a brake disc mount, i.e. rotor;
worm;
planetary;
with a fixed gear, no free play;
planetary hub is a detail that can arouse a lot of interest among cyclists. Its body contains the entire multi-stage transmission, so it does not need frequent adjustment and tuning, it has an excellent running resource and 100% protection from bad weather conditions. Very important point: when there is a planetary hub - gears can be switched even while standing still, but along with these advantages, it is worth noting the larger size and weight of this part.
Worm type bushings placed on bicycles at one speed. The main difference is that braking is carried out when the pedals are reversed. Frequent maintenance is not required for such bushings - they have a sealed housing with an abundance of lubrication, therefore they are also quite durable.
Fixed bike fans are madly in love bushings with no free play , providing torsion of pedals continuously during movement.
Two-star or flip-flop hubs are such a system that allows the wheel to turn as much as 180 degrees. At both ends there are fasteners for stars, where 2 stars with different diameters can be placed. The required sprocket size is determined based on the expected possible conditions ride. In addition, such bushings can simultaneously have both the possibility of a fixed and a freewheel - the "bicycle horse" can play the role of both a single-speed and a fixed gear.
Another exotic variety - shock absorber. It weighs quite a lot, its design is complex, and it is simply impractical to use it everywhere, since its performance of direct shock-absorbing functions is very mediocre. Such depreciation is carried out here as follows: the bushing moves along the guide bracket on the axis, in its free space there is an elastic element that absorbs vibrations, being both a spring and a damper. There are no strong depreciation abilities, therefore such bushings are little known.
There are differences in the bushings and the type of fastening of the rear stars. There are threaded and slotted type. The first one is gradually disappearing from bicycle production, since there are many disadvantages to the threaded connection of the bushing: during installation, it is easy to strip the thread, low rigidity and strength, uneven wear of the mechanism and the stars themselves, and a lot of energy loss in the assembly. The installation of such rear stars is carried out due to the cheapness and ease of production.
As for the spline connection, there are many advantages: less weight, greater rigidity due to the greater distance between the bearings, less energy loss - more wheel rolling, good fastening reliability, with proper use, it is almost impossible to tear the cassette from the splines, you can not change the entire cassette, and separate its stars if necessary.
How to choose bushing:
First of all, you need to decide where and how often you will ride a bike. It is important to pay attention to the weight of the transmitter, its resistance to loads and vibrations, moisture and dust resistance. For example, a road bike hub should never be used for aggressive cross-country riding.
In the event that you do not plan to seriously engage in any kind of cycling, but just want to ride around the city and simple conditions, then you can rely solely on your financial capabilities. Because the higher the level of the sleeve, the stronger and better it is, of course.
You also need to know how many spoke holes are on the flanges. The most common options are 36 and 32, but some types of bikes, such as road bikes, may be different. And if the sleeve has the wrong number of holes, it will not work to align it with the rim.
Which bearing to choose, industrial or bulk, you decide on your own based on driving conditions, we wrote about this above.
You also need to pay attention to the method of fastening the rear stars and their type, which can be slotted or threaded. The slots of cassettes from different manufacturers can be different in height and width, so it is sometimes impossible to combine them. If by chance your hub has a wider drum than necessary, spacers can be placed in the free space, the so-called. "spacers".
Among other things, pay attention to the type of mounting of the brake rotor. The most common among all are threaded "Centerlock" and with six bolts.
If financial possibilities allow and under certain driving conditions, planetary hubs are very good. In terms of convenience and duration of use, they have no equal, but they are more expensive, of course.
Bushing service.
Proper operation of the bushing requires periodic maintenance. It is important to carry out such manipulations as:
replacement of race bearings or bearing balls;
tightening cone nuts periodic;
on the brake sleeve, you need to adjust the pads;
lubrication on the inside of all parts, and every 500 km - a complete change of lubricant.
If such necessary measures are not taken, repair or even replacement of the bushing may be required. Symptoms confirming the need for replacement or repair are considered to be: reeling and rumbling of the bushing, wheels play while driving, the presence of extraneous sounds during rotation, the crunch of worn bearings, friction in bearings and poor rolling.
A loose, rattling or backlash bushing can be corrected by tightening with special wrenches. But here it is important not to overtighten, otherwise the wheel will start to rotate poorly, which will lead to damage to the bearings.
Bad rolling and extraneous sounds can be corrected with good lubrication or by replacing the bearings.
I would also like to advise you not to engage in self-repair without the necessary knowledge, experience and tools. Professional bicycle service workers can do everything efficiently and quickly by identifying the exact cause.
We will be happy to answer the remaining questions and help with the choice!
Hubs are one of the most important elements of a bike, be it expensive. sport bike or a simple city one, because the rolling speed, and hence the coefficient of performance (COP) of a bicycle, the high value of which is very important, depends on their quality, because the cyclist does not spend anything while riding, but his own strength. Not without reason, rolling bearings first appeared on bicycles, and later spread to many other machines and mechanisms.
PURPOSE:
Modern bushings differ in many ways: purpose, materials from which they are made, "stuffing". Bushings designed for mountain, hybrid and touring, road or city bikes differ in such indicators as weight, strength, quality of protection from external influences. The bushings of the front and rear wheels are also significantly different. Firstly, the load on the front wheel is much less than on the rear, which means that parts can be made smaller and lighter.
Secondly, a number of additional functions are assigned to the rear hub, such as the transfer of torque from the pedals to the wheel and many others: bicycle rear hubs almost always include freewheel mechanisms, often brake mechanisms, and sometimes internal gear shifting mechanisms. Internal gear hubs, the so-called planetary hubs, have so many differences from traditional ones that they will be discussed later in a separate article.
DESIGN FEATURES
General form most bushings are about the same. The simplest design is the front wheel hubs of a conventional bicycle. This is a cylindrical body, on the ends of which there are flanges with holes for fastening the spokes. Inside the housing there is an axle and bearing assemblies, closed by anthers of one kind or another. The device of the rear hub is noticeably more complicated. The general view is shown below. Designations in the diagram: 1 - eccentric, 2 - assembly of parts on the hub axis, 3, 15 - locknuts, 4, 5, 7, 13, 14 - washers, 8, 12 - sealing rings, 9, 11 - bearing cones, 10 - axle, 16 - anther, 17 - a hollow bolt for fastening the bushing drum to the body, 18 - a set of balls, 19 - a drum ("nut"), 20 - a washer.
Bushing bodies can be turned, cast or stamped, made of steel or aluminum alloys, although steel can already be considered obsolete. Turned and stamped bushings have better weight and strength characteristics than cast ones. Visually turned bushings can be distinguished by cutter marks on the outer surface (a spiral mark that looks like a very fine thread). Hubs designed for radial spoke wheels have hardened flanges to withstand purely radial loads, conventional hubs are not suitable for this. Bushing axles can be steel, aluminum or titanium. Recently, there has been a clear trend among high-end hubs towards the use of large diameter hollow axles that are lighter in weight and more rigid.
To date, the most widely used bushings with angular contact tapered rolling bearings. Such bearings consist of an outer and inner race, a set of balls and, sometimes, a cage. The cone screwed onto the hub axle acts as the inner race, and the hub body acts as the outer race. The main advantages of such bearings are maintainability and opportunity wear adjustments. A rather serious inconvenience is the complexity of assembly (many parts) and necessity adjustments.
Another type of bearing, previously found only in certain models of road bike hubs, is radial industrial (non-separable) bearings. Now they are increasingly distributed not only among road bikes, but also among mountain bikes. Their advantages include the best efficiency, ease of installation, no need for adjustment. Taking into account the easy replacement of the bearing, the resource of the bushing increases many times over. An interesting feature of some high end bushings is that they can be disassembled with just one hex wrench. But radial bearings do not tolerate the axial loads that sometimes occur in bicycle wheels.
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ABOUT REPLACING SPOKE
Mavic uses segmented flange hubs for special straight spokes. Replacing a spoke in a wheel assembled on such bushings is very simple. But now the wheels on such hubs are produced, as far as I know, only by Mavic itself and their cost is very high. |
FASTENING THE BUSHING AXLE TO THE BIKE FRAME
The wheel is attached to the bike by inserting the ends of the hub axle into the grooves on the frame stays and then tightening them, which can be done either with nuts screwed onto the ends of the axle, or using an eccentric mechanism or, as it is also called, a quick release mechanism. The convenience of using an eccentric coupler lies in the ability to quickly remove and install the wheel without the use of tools, which, if necessary, sometimes leave the bike somewhere, sometimes turns into a disadvantage in our country. The second advantage is the invariability of the bearing adjustment when tightening the eccentric after installing the wheel on the bike. All modern bushings, except for the cheapest ones, are equipped with an eccentric mechanism.
MANUFACTURERS
Shimano bushings are currently the most widely used. This is especially true of the rear hubs, which have a much more complex design than the front ones: many bikes are equipped with Shimano rear hubs and cheap front hubs from other manufacturers. Shimano only makes bushings with tapered bearings. Among mountain bike rear wheel hubs, only the Tourney hub has a very outdated threaded ratchet design, the rest are more progressive FreeHub type. Tourney and Altus/Acera bushings have the simplest mudguard, Alivio more advanced, Deore double guard, Deore LX and Deore XT double guard and improved bearing raceway finish, XTR the best finish, mudguard and stainless steel balls. In my opinion, Deore LX hubs are the best Shimano hubs in terms of price / quality ratio: Deore is much inferior in its characteristics, and Deore XT is much more expensive.
Another well-known mountain bike equipment manufacturer that produced tapered and industrial radial bearing hubs - SRAM stopped producing them since 2002. More precisely, he continues to produce only hubs with internal gear shifting.
Most inexpensive mountain bikes are equipped with Formula hubs (from Taiwan) with average performance. Unlike them, another Formula (from Italy) produces bushings designed for mounting disc brakes on industrial bearings. True, reviews about their products are very ambiguous - from enthusiastic to frankly negative.
Expensive and high-quality bushings are produced by companies such as DT Swiss, Hope, Hayes, American Classic and some others. There are also good bushings from subsidiaries of bicycle manufacturers: Coda, Scott Components, etc.
SERVICE
Immediately make a reservation that here we are talking only about the most common types of bushings. Their maintenance is reduced to maintenance of bearing bearings: their cleaning and relubrication, as well as adjustment, since the ratchet mechanisms ("nuts") of the bushings are conditionally non-separable, the mechanisms of the Torpedo-type bushings are maintenance-free, and other types of mechanisms are very rare and should have some specific maintenance instructions in the bike passport. With moderate use, the overhaul of the bushings for relubrication should be done once a season or once every 5000 km., With aggressive use, maintenance should be carried out more often. In cases of play in the bearings or extraneous sounds during wheel rotation, the bulkhead or adjustment must be carried out as soon as possible. If water gets into the bushings, it is also advisable to sort them out. The hubs of road and city bikes can be moved less often due to a more gentle mode of operation. Bushings on industrial bearings must also be serviced.
I must say that disassembling the hub on angular contact bearings requires cone wrenches and a cassette remover, in the case of the rear hub, so it is usually easier to take the bike to the bulkhead in the workshop. When changing the lubricant, it is necessary to use grease such as Litol, SHRUS or other high-quality grease. In the case of using tapered bearings, it is worth inspecting the surface of the balls and treadmills for cracks and chips and, if necessary, replace the balls and cones. Before laying fresh grease, it is necessary to properly clean the sleeve from the remnants of the used one. Do not dilute the grease with liquid oils, otherwise the grease will easily wash out and wear out quickly.
In addition to bearing maintenance, it is advisable to take this opportunity to inspect the bushings for cracks in the housings and, most importantly, on the flanges in the area of the spoke holes.
RESULTS
The operation of the bushing is very much dependent on the type of bearings, the quality of their processing, as well as the quality of the seals. The softness and ease of rotation of the bearings is determined by the manufacturing accuracy, the type of polishing of the treadmills, and their surface hardening. The higher the surface hardness of the treadmills, the less resistance there will be to rotation of the hub, especially under load, but durability may be reduced due to the tendency for material to chip.
An excessively tight stuffing box will significantly slow down the rotation of the bushing, and a free one will perform its functions poorly. All modern bushings except the lowest level are double sealed. Expensive bushings such as DT Swiss use a labyrinth seal that more effectively protects the inside of the bushing. At the same time, any such protection only helps to protect the bearings from flying dirt and water, so you should not once again dip the bushings into the water.
