What does the wheel consist of?
Bicycle wheels are the most conservative component. Of course, there are models on cast disks, all-round wheels are put on track models, but they are in the minority. Still, the majority of bicycles are equipped with spoke wheels.
- ordinary sleeve;
- connecting knitting needles;
- rim protective tape (flipper);
- camera and tire;
- disc (on models with disc brakes).
The hub is the axial part of the wheel, it is an assembly of the central axle, bearings and tapered retainers. Cone bearing systems are most often mounted on bushings with open type bearings. They can also be equipped with sealed bearings or slips.
Open bearing bush
Rim. supporting structure, metal ring. The rims are made mostly of aluminum, with carbon rims being used on expensive models. In terms of rigidity and power, they are divided into three types:
- single-walled. the outer and inner surfaces have one line of contact (jumper);
- double. the inner surface is attached to the sidewalls, separated from the outer;
- triple. the strongest and most durable option: the inner wall is also fixed to the sidewalls, but, unlike the double rim, the triple rim has an additional wall in the middle.
Types of rims for bicycle wheels
Vertical bridges form channels running in the direction of rotation. According to the number of such channels, modern rims are divided into one, three- and five-piece:
Spokes. elements connecting the hub to the rim. They perform the functions of securing, distributing loads along the rim and central axis and mitigating vibrations during movement. The rim is perforated, each hole is designed to hold one spoke. The number of spokes is set on a bicycle wheel in multiples of four. Depending on the model, their number varies. from 28 to 40 on average.
The number of spokes for the front wheel is usually less than the number for the rear. This is due to the fact that the bulk of the load falls on the rear of the bike, and there the wheel must be stronger.
- standard (rolled). constant circular cross-section along the entire length from the bushing attachment to the tip;
- aerodynamic (blade-like). elliptical or rectangular profile;
- variable cross-section (pulled). standard cross-section at the heads and tapering towards the middle.
The inner tube is the inside of the tire that holds the pressurized air inside. Tire. the outer shell, in contact with the road, absorbs bumps, protects the camera. The tire is made of a harder rubber than the tube.
Rim tape, or flipper, is a rubber lining under the tube to protect it from puncture on the spoke tips. Dynamic loads force the walls of the chamber to bend, which causes them to be pressed against the rim surface. Without a flipper, the camera can be pushed into the hole with the spoke tip. This problem is more pronounced on the rear wheel, where the loads are higher, but the presence of a flipper is mandatory on the front. The torn tape must be replaced with a new one. A proven homemade option. glue the rim with several layers of electrical tape, except for the hole for the nipple.
Main types of bearings
The main differences between parts. by type of structure: rolling and sliding.
The sliding bearings are driven by the process of rotation of two elements relative to each other tangentially. Parts are made from materials with a low coefficient of friction, such as steel alloys, bronze and others. Two bearing parts are in direct contact with each other, so this mechanism is more prone to abrasion than rolling bearings.
A feature of rolling bearings is the presence of balls (rolling bodies), which are placed between two rings. They are used in such movable bicycle structures as carriage, bushings, steering column
For applications where pressure and abrasion resistance is an important requirement. There are two main types: bulk (separator) and industrial
The separator is an open mechanism. It is a cage in which the balls are distributed along the groove and fixed with a flare nut. The mechanism is placed directly in the workpiece, for example, in a carriage mill. Advantages of this type: easy removal and installation, which allows you to adjust the mechanism even in the field; the components of the mechanism can be replaced separately. However, the cage bearing requires frequent adjustment and cleaning of the mechanism from clogging.
How To Replace A Freehub Body On A Bike Wheel
The industrial one is characterized by a closed mechanism that fits completely into a movable unit. The system provides protection from external influences in the form of dirt, moisture, which significantly extends the service life of the mechanism. Clogging does not get inside an industrial bearing with a closed housing, the lubrication is permanently retained. This mechanism does not need adjustment. If necessary (wear, breakdown), the entire bearing is changed, which is problematic to do in the field. And industrial mechanisms are also distinguished by a higher price.
It is worth noting one more type of bearings, which are made of ceramics or cermets. They are highly resistant to wear and corrosion, temperature changes. These parts can be found in high-end bicycle mechanisms.
When to Service the Rear Hub
To ensure that bike parts are always in perfect technical condition, they must be regularly serviced. If we consider the rear hub of the bicycle, then for it you will need:
- periodically tighten the body;
- regularly change the bearing balls;
- at the next disassembly, lubricate all internal parts of the case;
- adjust the brake hub from time to time.
Dismantling the rear wheel itself is as easy as shelling pears, but the process of removing and disassembling / assembling the rear bicycle hub is much more difficult. And nevertheless, without such regular maintenance of the part in question, it may soon need to be overhauled or replaced.
Signs that indicate an urgent need for service on the rear bicycle hub:
- when driving, there is a strong wheel play;
- the crunch of bearings is clearly audible (this means that they are simply worn out);
- on the move, the bike body rattles and staggers;
- rolling dynamics is bad.
It is worth knowing some of the features of eliminating a particular symptom:
- If the rear hub casing is spinning, its looseness, then this can be eliminated by tightening the fastening nuts.
- If the movement of the rear wheel is difficult, then it may be necessary to loosen the retaining nut a little. most likely, too much force was applied when tightening it.
- If extraneous sounds appear when the bike is moving and the roll-forward deteriorates, you will need to replace the bearings or completely lubricate the rear hub housing.
Replacing the camera
First of all, you need to lower the wheel. unscrew the cap and release the air by pressing the nipple. If the chamber is damaged and there is no air in it, simply remove the cap. To remove the tire, you will need mounting paddles, with which it will be convenient to pry on the tube until it becomes easy to pull it off the rim.
The camera can be replaced without the need for tools. First, the nipple is inserted into the hole in the rim, after which the tire is evenly put on the rim. Finally, the camera needs to be pumped up to the desired state.
Installing the rear wheel
To carry out the installation correctly, assemble everything in place should be clearly in the reverse order.
Place the chain on the smallest sprocket, insert the wheel onto the frame mount
In this case, it is important to make sure that the axle is fully inserted into the grooves of the frame.
- We fasten the nuts or eccentrics, they should be tightened well so that the wheel firmly sits on the frame.
- Fasten rim brakes if fitted. Return to the previous position in exactly the opposite order, otherwise the next trip may not end very well.
After the installation process, it is advisable to check the correctness of the actions performed by means of a short test drive to see how your bike will behave on the road after the updates.
Maintenance and diagnostics of the rear wheel is a mandatory procedure to maintain the health of the mechanisms.
When to remove the rear wheel
It is unlikely that the idea of unscrewing the chassis from the bicycle frame would just come to mind, unless, of course, a person specializes in bicycle dismantling. But this is a completely different case. Dismantling the rear wheel will be required if the following problems are observed:
- noticeable damage to the rim;
- complete wear when a wheel needs to be replaced;
- a flat tire or a burst tire;
- bulkhead bushing.
This includes the planned replacement of the rear sprocket system and chain.
Usually one wrench of the appropriate size is enough, with which the nuts are removed one by one. If the hub axle turns, then the nuts are unscrewed simultaneously in different directions. It is recommended to use open-end wrenches or box wrenches. The adjustable version is undesirable, as its thick horns “eat up” the corners of the nut due to loose fit and sliding.
First, remove all unnecessary items from the bike that may be on it. And it is also better to unscrew all kinds of mirrors, flashlights and other little things that can be damaged during work.
Bicycle Coaster Brake Repair and Service
- We turn the bike upside down, put it on the handlebar and seat. You can do without a special rack for repairing a bicycle, the main thing is to give it a stable position.
- We find out the type of brakes installed for further action. As usual, these are disc or rim brakes:
- disc brake. It will make it easier to remove the wheel;
- The rim brake of the V-brake type must first be released and removed, otherwise further dismantling of the wheel will no longer be possible. (It is not difficult to release the brakes, for this you need to move the cable to the side of the fastening screw, move the levers, removing the end of the cable from the clamp, lower it down and spread the brake levers to the sides).
- Then we act depending on the type of fastening of the rear wheel to the bicycle axle. We unscrew the nuts with a wrench (one or two) or, if the mount is a disc eccentric, unscrew the brake lever and twist the wheel.
- The chain passing through the gearshift system is neatly removed from the sprockets.
The wheel is removed. Now you can carry out all the necessary further manipulations: replacement, adjustment, lubrication of parts.
Assembling and installing the rear wheel on the bike
A quality wheel repair is not only about disassembling, replacing, lubricating or adjusting. At the last stage, all this chaos must be collected in reverse order. All parts of the bushing mechanism are placed in the drum and carefully secured with locknuts. The drum is pushed onto the spokes, after which they must be tightened by the number of revolutions by which they were loosened.
Tightening the spoke nuts is done in the opposite direction to loosening. Here you need to remember the direction of loosening in order to tighten correctly. If the drum dangles, then you need to tighten the spokes harder.
The cassette is put on the sleeve in the following order:
- main stars;
- single stars, small stars;
- tightening the cassette mechanism with a whip.
All that remains is to put the rear wheel on the frame. A chain is put on one of the stars, and the wheel is inserted into the grooves of the frame. To top it off, all that remains is to tighten the nuts or eccentrics on both sides. After assembly, you need to twist the pedals and see if the chain runs normally in the stars. We turn the bike over and begin to ride calmly!
Anyone who actively rides a bicycle will have to deal with wheel problems one way or another. Despite the ease of maintenance, the wheel can be time-consuming at first. However, if you remember how important wheels are to a bicycle, it turns out to be not so much. What’s more, with experience, a wheel bulkhead will take minutes.