Types of bike frame mounts
Consider what mounts are on the wheel axles. Traditionally, they are presented in three types:
- nut. on budget road and high-speed models, the axle is fixed to the dropouts with two nuts;
- splined. have an analogy with nuts, instead of them flat splined linings are superimposed on the axis;
- cams. a common mount on speed bikes, the spring is fixed with a clamping nut and a lever.
From the standpoint of convenience, eccentrics are better than nuts and splines. the wheels are removed and put in half a minute, the mechanism is simple and relatively durable. However, the fastening force does not correspond to aggressive driving conditions. too high loads on the fasteners.
Hybrid eccentric-nut mountings have been invented specifically for these purposes. On the right side, the axle is attached to the dropout through a regular nut, and on the left it is clamped with a lever. The installation of such an eccentric looks like this:
- The axle is threaded through the linkage through the entire hub body.
- The thread is screwed onto the dropout of the fork or stays.
- A nut is thrown from above.
- The eccentric fixed on the right side is clamped with a conventional lever.
This way, the wheel will not loosen at high speed off-road. If an ordinary eccentric no longer rescues, it makes sense to choose just this type of attachment.
Rear hubs. varieties and fundamental differences
The arrangement of axle assemblies for the rear wheels is more complicated than for the front wheels. we have already mentioned the built-in freewheel mechanism above. In addition, the bushings are equipped with special inserts for a cassette, ratchet, brake discs. On planetary shift models, the rear hubs are complex gear systems.
And of course, on classic Soviet bicycles and modern city bikes, they are equipped with a braking mechanism:
By design, rear bicycle hubs are divided into types:
- classic, without brakes, with mounting for a cassette and / or disc;
- brake with an internal drum-shoe mechanism;
- without freewheel.
Classic narrow bushings are similar in appearance to the front ones. Installed on high-speed models, they have a built-in freewheel mechanism. The principle of operation consists only in the direct transfer of forces from the pedals through the transmission to the axle. Fixation of the bushing is provided by pawls, which, in the absence of applied forces, hold the body, due to which the wheel rotates independently by inertia.
The planetary model is a model that arouses keen interest among cyclists. The entire multi-stage transmission is hidden in the hub housing, so it does not require adjustment, it is 100% protected from harmful weather conditions and has a very high running life.
The classic planetary system. three gears: standard, high and low. The picture shows a model with a foot brake, as on Soviet city bikes, but there are also planetary without brakes. High-speed transmissions are available in five, seven and eight gears. In terms of the number of gear ratios, they are comparable to 24-speed cassette systems.
Repair of planetary gears is not provided, they serve only once. Difficulties can arise with the maintenance of the axle assembly and bearings if they wear out before the gearshift mechanism. There are also a couple of other disadvantages. high weight and relatively low impact strength. Planet cars are put on urban models, as they wear out quickly in aggressive conditions.
Worm and drum brake hubs are mounted on the rear wheels of single speed bicycles. Braking occurs when pedaling backward. The mechanism works according to the following algorithm:
- When the driven sprocket moves backward, the freewheel mechanism is activated. All foot brake systems have some margin where the sprocket can turn back 1/8 of a turn. This, in turn, reduces braking performance.
- Stopping the body.
- Drum rotation and brake pad spreading, wheel stop.
- In the absence of applied forces on the pedal, the spring of the drum should instantly rebound. If this does not happen (indicates wear of the mechanism), the wheel must be released by scrolling the pedals forward.
The worm brake mechanism differs from the drum brake in that a threaded auger is applied to the inner wall of the housing when the star rotates in the opposite direction. Benefits of brake bushings:
- does not require frequent maintenance. this is facilitated by a sealed housing and a large amount of lubricant;
- if necessary, it is easy to remove and lubricate the bearing-axle part without touching the brakes;
- relatively light weight, good strength.
Flip-flop, or two-star hub, is a system that allows the wheel to flip 180 degrees. At both ends there are two stars of different diameters, depending on the intended driving conditions, turn the wheel with a large or small sprocket.
The two-star model does not have a built-in braking mechanism or even a free wheel. The non-free wheel rear hub transmits forces in both directions. from pedals to wheel and from wheels to pedals. Thanks to this, the dynamics of the bike is noticeably increased compared to free-wheeling models.
Bushings are a relatively new and little-known variety. It is installed on the front axle and serves as a wheel vibration damper. When the bicycle moves, it reciprocates up and down along the guide bracket. To achieve a shock-absorbing effect, the outside is bordered by elastic elastic inserts.
Bicycle hub device
Mechanisms of this type first appeared on bicycles. The operation of the bushing is based on rolling bearings. ball parts for transferring torque from the axle to the bushing housing and rotating the wheel. Three main types of rolling bearings have become widespread. ball embankment, separator and closed (industrial).
The front hub has a classic and versatile design:
- wheel axle with attachments to dropouts;
- protective inserts. anthers;
- external spokes.
The design is identical on any type of bike, from standard road bikes to special-purpose high-speed bikes. Of course, with the similarity of the general structure of the bushings, they will differ in material, weight, strength, degree of protection and running resource.
Front hubs are lighter and simpler than rear hubs. This is due to the lower dynamic load on the front of the bike. In addition, the complexity of the rear mechanism in comparison with the front is associated with the presence of free wheeling. It is installed on all bikes except fix bikes. It is also easier to do it yourself before.
What are the bike hub bodies? By the type of production, they are divided into:
Compared to turned and stamped (rolled) bushings, cast bushings have a low margin of safety, and are also slightly inferior to them in weight. However, with proper operation and timely maintenance, they can also serve for a long time without wheel alignment. The materials used are aluminum alloys for casting and dots, steel is used in stamping. The axle is made of steel, aluminum and less often titanium.
Most bicycle hubs are fitted with radial thrust tapered bearings. The part is attached in this way:
- A cone is screwed onto the axle.
- A bearing is mounted on top of the housing.
- Outside fits snugly against the hub body.
Bearings of this type have become widespread due to their high running resource, the ability to sort out and adjust as they wear out. Some mountain and road bikes are equipped with industrial radial bearings. Compared to classic open ball flush systems, they do not require disassembly and are easy to install. With lower rolling resistance and higher efficiency, these bearings significantly increase the running life of the bushing.
Bicycle Hub A to Z
Is a bicycle a simple or complex mechanism? It all depends on which side to look at and which one is big before our eyes. For example, an MTB device can be called complex compared to a city bike, but simple relative to a car. Nevertheless, even the most ordinary model is a system of interconnected nodes. It will not be possible to single out any one of them. the operation is ensured by the well-coordinated work of all mechanisms. These are the wheel hubs.
Bicycle hubs are responsible for the distribution of circular and radial loads, uniform wheel rotation, rolling, and in some cases. for shifting gears and stopping the bike. Based on this, we understand that the condition of the bushings directly affects the ride quality. And if so, let’s dwell on this mechanism in more detail: how it works, how the bushings differ from each other, how to service this unit.
Bulkhead bushing. simple, fast, high quality
Sooner or later, the need to get into the axle system of the wheel and repair it arises for any cyclist, even the owner of a standard city bike. Over time, the grease ages, the bearings wear out, washers may break, and the axle is not eternal.
Bushing malfunctions are determined very simply:
- deterioration of the roll, the average speed of the bike decreases;
- crunch of bearings;
- leakage of grease;
- crack in the case.
To eliminate the last problem, disassembly of the wheel will be required; in other cases, you can do without spacing. In general, it is better to entrust the operation to remove the case to the master. it will be easy to remove the knitting needles, but putting it back on and correctly adjusting it will not always work.
The procedure for disassembling the bushings yourself:
- Remove wheels from dropouts.
- Loosen the fixing nuts on the axle using suitable spanners. It is necessary to remove the cassette from the rear wheel using a puller.
- The bearings can be locked with rings. Use a thin screwdriver to gently pry them.
- We now have access to the bearings. We take them out and carefully set them aside. It is undesirable for the balls to crumble.
- Pull the axle out of the body cavity.
- Wipe the interior space and parts from old grease. Place the parts neatly on a clean cloth.
Everything About BMX Hubs: Vital BMX Explained
During a preventive overhaul, the parts and the body are lubricated, and then the assembly is assembled in the reverse order. As you can see, making a bulkhead is very simple, half an hour at most.
Note: it is better to purchase a special lubricant for the bushings, and separately on the bearings, you can apply thick grease.
But what if you need to replace bearings, axles, washers, or even the entire bushing? It is better to contact a workshop to replace the entire unit. To be more precise, it is necessary to remap the wheel. Otherwise, it will not be difficult to repair the internal mechanism on your own:
- We select bearings by standard size. They are installed on one side with the outside, on the other. with the inside, the main thing is not to confuse.
- After disassembly, it is better to fold all the parts in the order in which they were installed on the bushing. it is easier to reassemble later.
- It is necessary to lubricate the inner cavity first, then the axle and only the bearings last.
- After the assembly is complete, we install the wheels on the bike and check the operation of the bushings. Backlash, braking, grease leakage. all these are signs of an incorrect bulkhead.
The fastening nuts must be tight, but must not interfere with the rotation of the axle. A weak tightening will cause play, and too strong an additional load on the bearings and difficult rotation. It is easy to disassemble and assemble the hub, from the rear everything is complicated by removing the cassette and brake disc. In addition, its device due to the built-in freewheel mechanism is (at least) more complicated than that of the front one, so it should be sorted out with special care.
Single Speed Hub (Singlespeed)
The simplest type of bushings. Only one sprocket is used to transmit power to the wheel. Since when installing such a bushing there is no switch that would tighten the chain, they are usually installed in frames with horizontal dropouts, which allow you to adjust the tension yourself by moving the wheel back and forth.
If you want to use this hub on a bike with vertical dropouts, you will need to install a chain tensioner.
These bushings are often found on touring and city bikes and are usually equipped with a foot brake. By turning the pedals back, you activate the mechanism and the hub starts to brake.
Another option for a single speed hub is the fixed hub. There is no ratchet in it and the sprocket constantly rotates with the wheel. The downside to this hub is that you can’t stop pedaling without locking the wheel. The advantages include durability and low cost. These bushings are suitable for short distance travel on flat terrain.
What Langtu offers
For any question. whether it is the repair of a skewed bicycle wheels or a complete re-spacing of the rim. please contact our masters who will provide you with high-quality and fast service. We have all the necessary tools, as well as a machine on which it is possible to carry out any manipulations at a professional level.
Among the most common jobs, the most popular is replacing the spokes of bicycle wheels. This service includes removing old rods, correctly and consistently installing new ones, and adjusting their correct tension. We also help to get rid of:
- complex curvature of the rim;
- inaccurate operation of bearings in the sleeve;
- an old tube or tire;
- problems with the stars.
Maintenance of bicycle wheels includes rare breakdowns of various difficulties.
Bicycle Wheels: Hubs
Bicycle hubs play one of the most important roles, they allow the wheel to rotate freely, while keeping it securely on the frame or fork. In addition, often, with the help of bushings, we brake, and in the case of the rear, we also give the bike acceleration.
They consist of an axle, bearings and a housing on which we attach the spokes. They also have either a brake disc mount, a sprocket mount, or both. Today we will talk about the types of bushings (mainly rear).
The article will address the following issues:
Rear hub features 
Rear hubs are generally asymmetrical as the rear sprocket or cassette is located on the right side. Therefore, the right flange of the rear hub is closer to the middle of the hub, and as a result, the spokes on the right side are 1-2 mm shorter than the left side.
Bicycle Hubs & Rear Wheel Axle | Repair and maintenance
Most modern bicycles are assembled on tube wheels, so one of the most common and commonplace problems is their puncture. Every cyclist should be able to cope with this task, but at first it is better to use the services of a workshop and observe the work of specialists.
If the repair of a puncture of a bicycle wheel with the necessary tools can be carried out in the field, then the rest of the problems have much more significant consequences and it will take more time, skills and tools to eliminate them. Let’s take a look at all of the most popular bicycle wheel problems:
- deformation of the rim: the formation of an eight, an egg;
- broken spoke;
- wear of the spokes, loss of their elasticity;
- damage to the bearings of the front and rear bushings;
- the curvature of the rear hub axle for the ratchet;
- an eccentric bursting under pressure;
- wear of the teeth of the rear wheel sprocket.
Our company has sufficient equipment, and we are ready to solve your problem if the repair of this breakdown is cheaper than a complete replacement of parts. The cost of work differs depending on the complexity of their implementation. For a better understanding, it is worth considering typical problems in detail.
The planetary hub also has only one star and all the restrictions for singspeed hubs apply here as well. These bushings appeared at the beginning of the 20th century and had 3 speeds.
Modern counterparts can have 7-8 speeds, and sometimes even more. The hub design itself is a great topic for another article, so we won’t go too deep into it.
Let’s just say that you can switch gears on such a bushing even while standing still.
The shifting mechanism itself is hidden inside the hub and is well protected from external influences. This makes planetary hubs great for harsh weather conditions.
Virtually no moisture gets inside, and gears are switched even at 15! The main disadvantage is the difficult self-service of such a hub and problematic mounting / dismantling of the wheel (if you made it through or something like that).
Ratchet and drum
Often these 2 types are confused. The first is a threaded bushing for screwing in ratchet sprockets. It was popular until the late 1980s, when the expensive ratchet mechanism was decided not to be thrown away every time the stars were replaced. The photo below shows a ratchet, a bushing for it, a bushing with a drum, and a cassette for a bushing with a drum. The main differences in the way the stars are set.
High-precision tools are needed to thread the bushing and ratchet, otherwise it will be impossible to install the ratchet parallel to the bushing itself and thus it will be impossible to maintain alignment. This translates into either problems with switching on cheap versions, or the price of the final product.
Bushings with a drum are devoid of such a drawback, plus the stars for them are much easier to produce.
Another advantage of bushings with a drum is the location of the bearing, it is closer to the dropout and the load on it is less, therefore, the axle will break less often, and the bearing will live longer.
In modern bushings, 3-4 industrial bearings are used and, with timely service, they work for a very long time.
The drum is many times better and easier to use. To fix the cassette on it, a locknut is used, on which there are practically no loads. You just put on the cassette, and the slots prevent it from turning.
Of course, there are some peculiarities, like the use of cassettes on a spider with an aluminum drum. Otherwise you might just ditch the drum.
Rim irregularities can indirectly cause several other problems listed in the list. Therefore, repairing bicycle wheels is one of the most important jobs that require timeliness and accuracy. Wheel unevenness has the following consequences:
- Changing the tension in the knitting needles. If an eight appears on the wheel on impact, the tension on the spokes on one of the sides is weakened. This means that the wheel deforms and this leads to unnecessary stress on the hub bearings and earlier wheel failure.
- A similar situation occurs during adjustments: on one side, the spokes will always be pulled a little tighter to keep the rim straight, and this automatically increases the chance of the spoke breaking during natural stress. Accordingly, constant corrections of irregularities entail a terrible spread and imbalance in the tension of the spokes.
- Riding on a crooked rim affects not only the spokes, but the hubs as well. Their wear and tear increases and the likelihood that a bicycle wheel hub repair will be required.
Among other things, on weak and worn spokes, as well as on a crooked rim, acceleration and average speed will decrease.
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History of appearance
The history of the appearance of the hub is closely related to the improvement of the bicycle. Having appeared at the beginning of the 19th century, the bicycle was constantly undergoing changes. At the end of the same century, the French engineer au designed a bushing with a free wheeling. As a result, there was no need to constantly pedal. Now you can stop the pedals when accelerating or descending. Cycling made it much easier.
Types of bushings and their use
A bushing is a part of a mechanism and machines, the task of which is to create a rotational movement. Not a single vehicle, industrial and household machine tools can do without this small part.
Types of bushings
The sleeve most often has the shape of a cylinder or a cone, there is a hole in the center, thanks to which it is interfaced with other elements. They can also be split, split and threaded. Depending on the purpose, the following types of bushings are distinguished:
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The bushing body can be point, stamped, or cast. For the manufacture of this part, steel or aluminum alloys are used. In terms of strength, point and stamped bushings are considered the best.
Depending on the use of the sleeve, it has its own design features. For example, there are 3 types of hubs used for the rear wheel of a bicycle. They can be brake with or without free play. Also, the bushing can be free running with no brakes.
In addition to vehicles, bushings are used in industry. Bronze products are in demand in rolled metal products. They have a cylindrical shape with a hole of a certain diameter. With their help, elements of various mechanisms and structures are connected. Bushings are used in mechanical engineering in the production of excavators and other specialized equipment. The distinguishing feature of copper bushings is their ductility, strength and good resistance to rust formation. Copper bushings are made on the basis of two technologies.
Broken rear hub
The most common rear wheel hub failure is a loose cone or overtightening. Loosening of the taper leads to an increase in the wheel axle play. If the situation is the opposite, when the cone is overtightened, then the ease of movement of the bike disappears. In the worst case, a characteristic crunching sound can be heard in the bearings. Both situations are emergency, so you need to immediately start repairing the rear hub.
Eccentric locking rear hub.
Rear hub axle.
To do this, you will need to dismantle the rear wheel. On some models with an eccentric lock, no wrenches are required to remove the wheel. On children’s or budget models, the wheel is fixed with two nuts, so wrenches are required.
To tighten the cone, or to eliminate the backlash, you will need: a 17 mm key and a 15 mm key. First, loosen the locknut, then tighten or, conversely, loosen the flare nut until the desired result is obtained. As a result, we achieve the elimination of backlash and then tighten the lock nut.
Poor quality parts will cause the hub axle to bend or break. Only a replacement with a different axle, of a higher quality, will be the best way out of this situation.
Varieties of rear bicycle hubs, how they differ from each other
The hub is located in the center of the wheel and rotates on bearings. Collapsible balls or factory-made universal sealed bearings are used as bearings. The bearing carries all the pressure of the bike while riding, so its quality must be high.
The hub is spoked to the wheel rim. Outdated Torpedo-type hubs contain a brake drum inside the structure, with which the cyclist brakes by reverse pedaling.
The modern rear bicycle hub features a ratchet mechanism and a cassette star cassette slips over the drum. On the ratchet hub, the bearings are closer to the center, so the load is not evenly distributed. Hubs of this type are installed on teenage or budget adult bikes.
The cassette hub is another popular type of rear hub. It has slots on which a cassette with stars is fitted and is fixed with a cassette nut. These bushings are more reliable, the bearings are farther from the center of the hub, so the bike can support up to 120 kg.
The third type of rear hubs is a hub with a planetary gearshift system. It combines the functions of the hub and the gearshift mechanism of the bicycle.
The entire mechanism is located inside the hub and is protected from dust and moisture. The chain on a bicycle with such a hub lasts longer, since it does not change its position. The planetary hub has a high degree of reliability.
SRAM’s 3-speed planetary hub is very simple in design. But it is better not to disassemble the 5 and 7-speed ones. Planetary gears are installed in a special position. this requires a special tool.
Spoke is the order in which the hub, spokes, and rim are fastened together. There are two main types of wheel lacing: radial and cross.
In the Radial view, the spoke does not intersect with the others. When knitting with a cross, a knitting needle is crossed with the rest of the knitting needles several times, depending on the selected spoke method. On widespread 26-inch wheels, three-cross lacing is more commonly used.
A modern bicycle has two wheels, usually of the same diameter. The rear wheel is usually driven and is driven by a bicycle chain.
The wheel consists of a hub, spokes, rim, tube and tire. Sometimes the tube and the tire are one piece, that is, a tubeless tire.
The hub is connected to the wheel rim using spokes, the number of which ranges from 12 to 48. Prestigious models of bicycles with a frame made of composite materials are often equipped with wheels, the spokes of which are made of carbon.
The size of a bicycle wheel is traditionally determined by the outer diameter of the tire in inches. from 14 to 29 (1 inch = 2.54 cm). Mountain bike is usually equipped with 26 “wheels, and hybrid or touring. 28”.
The rear wheels of sports bicycles do not contain spokes, so they consist of a solid disc. This design increases the rigidity of the wheel and reduces the resistance of the oncoming air at high speeds. The only drawback is the increased windage, which adds trouble for riders in a crosswind.
The simplest rims are single-walled. The rim profile resembles the letter U. After adding an additional bridge to the profile, a reinforced rim type is obtained. double-walled. Such a rim is stronger, it is less afraid of obstacles and holes on the roads. The most powerful type of rim is three-walled, when another bridge is inserted inside.
In the manufacture of bicycle wheel rims, steel or aluminum alloys are used in most cases. Steel rims are cheaper, but heavier and more susceptible to corrosion. In recent years, more and more lightweight composite materials are used: carbon and plastic.
Freehubs Explained: Everything You Need To Know About Road Bike Freehubs
Bicycle rear wheel device
Bicycle wheel spoke
A very vulnerable element. In addition to the weight of the cyclist, it is subject to impacts on uneven roads. The nipple is used to fix the spoke in the rim. The most common knitting needles are made from steel or aluminum.
The steel spokes must be chromed. Stainless steel spokes have proven themselves well. They are durable and resistant to corrosion.
The spoke consists of four parts:
The nipple must be of the same material as the spoke. Otherwise, due to electrochemical corrosion, it is difficult to tighten and replace the spoke. The spokes are tightened only with a spoke wrench, in no case with pliers or other tools at hand.
- Rolled knitting needle. budget option.
- The pulled spoke is lighter in weight but more expensive.
- Flat spoke. the most expensive, significantly superior to other types both in weight and in resistance to oncoming air flow.
Bushing lubrication (maintenance)
A tightly running wheel means the hub bearings require maintenance. To get to the bearings on the bushing, you must first remove the stars. This can only be done with a special puller. It is allowed to lubricate the bearings with liquid grease, filling it with a medical syringe.
Teflon-based grease has proven itself well. it is a widely used grease that is effective, versatile, and not the most expensive. However, this grease evaporates easily, so green grease can be mixed with Teflon-based grease to increase viscosity.
A crunchy sound of a spinning wheel after assembly means that sand has entered the bearing, or defects have appeared on the rubbing surfaces. Disassemble and lubricate again or replace defective parts.