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 cut threads on the sleeve and on the ratchet, otherwise it will be impossible to install the ratchet parallel to the sleeve 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, such as the use of cassettes on the “spider” with an aluminum drum. Otherwise you might just ditch the drum.
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 chrome plated. Stainless steel spokes have proven themselves well. They are durable and resistant to corrosion.
The spoke consists of four parts:
- Head The head is fixed to the bushing.
- Thread. A nipple is screwed onto the thread.
- Nipple. The nipple secures the spoke to the rim.
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.
- A flat spoke is the most expensive, significantly superior to other types both in weight and in resistance to oncoming air flow.
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 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 an excellent choice for harsh weather conditions. Virtually no moisture gets inside, and the 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).
Replacing the bike camera
To remove the tire and remove the damaged chamber, it is necessary to remove the remaining air: the cap is unscrewed and the wheel is lowered by continuous pressing on the nipple. If there is no air in the tire, which is more often the case with punctures, then simply unscrew the cap.
To remove the tire, you need special paddles. Of course, you can pry the camera with an ordinary screwdriver and even a knife, but it is better to have a professional tool. With the help of assemblies, the tire is pushed on from the side opposite to the nipple. As soon as it starts to tighten, you need to pry the sides a little further, until a sufficiently free part of the tire is formed, and it can be safely pulled off the rim.
Before removing the bike, turn it over and place it on the saddle and handlebars. It is better to remove awnings in the form of a mirror, a bell and a lantern in advance so as not to damage them under the weight of the frame. V-brakes are first released and disassembled, otherwise they will not allow the wheel to be pulled out freely. With disc models, everything is easier. you can immediately remove the wheel.
I must say that the removal process itself consists only in unscrewing the eccentric or unscrewing the fastening nuts from the axis of the bushing, who has something. If the mount is an eccentric, simply unscrew the handles and twist the wheel. The nut fastening is loosened with one or two wrenches.
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.
Shimano and Sram Cassette Compatibility
The standard for Shimano and Sram cassettes is the same for 8-9-10 speed cassettes. You can use Shimano cassettes in conjunction with a Sram derailleur and vice versa. In this case, the very fastening of the cassette to the drum remains unchanged.
But the Sram XD standard for 10-11-12 speed cassettes will require a special drum. It is somewhat similar to a mixture of a classic ratchet and a spline drum. You can estimate the difference below, on the left is a regular drum, on the right is XD.
Previously, rear hubs with a width of 120, 126mm were used, but these times are long gone. Now we have: 135, 142, 148, 150, 158 and fig knows how many more standards for the width of the bushing come up with at this very moment. The diameter of the axis is a little easier, it is 10 and 12 mm.
The front hub is easier. Width 100 or 110mm, and axle diameter 10, 15 and 20mm.
The width of the sleeve is always measured from the lock nut to the lock nut.
Experienced cyclists will find it easy to figure out how to disassemble the rear wheel of a mountain bike. Flip the bike over and unscrew the eccentric or axle mounting nuts, whichever is standing. For this, one key is enough, suitable for the nuts. It is necessary to have a box or open-end wrench with you, but set aside the adjustable wrench, because it “eats” the corners of the nuts.
Not sure how to disassemble a mountain bike rear hub? Then remove the carriage from the axle with a puller and a whip. The retaining ring must be opened. Carefully remove the washers and bearing (try to put them side by side so as not to get lost). Pull the axle out completely and inspect for damage, lubricate with oil if necessary.
How to disassemble a mountain bike
There are several reasons why you will need to disassemble a mountain bike:
- technical repair,
- replacement parts,
- long distance transportation.
Naturally, for this, you must always have a full set of tools with you, a stand for the frame, because sometimes you have to disassemble the bike directly on the way.
In order to understand how to disassemble a fork on a mountain bike, you need to remove the front wheel and handlebar. Pull out the plug and use a screwdriver to remove the tapered support ring. Next, you need to unscrew the lower bolts, remove the elastomer.
Since water or oil will start leaking from the plug, you need to have a rag with you. Make sure you have a lot of rags near you. Then inspect the fork for cracks. If they are not, then just grease it with oil.
Use a screwdriver to remove the plug from the bicycle pedals, unscrew the locknut. The key must be in a stationary position to hold the axle. Unscrew the cone and remove the bearings.
Tip: Try to have a magnet with you, as small parts can fly out when removing the pedals.
It is easy to understand how to disassemble the carriage on a mountain bike, the main thing is to have a wrench, screwdriver, squeeze and a small hammer with you. Before starting the process, remove all the dirt, so you can do all the actions several times faster. Remove the plugs from the connecting rods and unscrew their fastening nuts. To do this, use squeeze. Remove the connecting rod (insert the squeeze with the other end and screw into the connecting rod). You need to start removing the carriage where there are no transmission stars.
Types and arrangement of the rear / front hub of a mountain bike
In the MTB class, only two types of sleeve mechanisms are common: axle-cone-ball bearing and axle-industrial bearing. By the name of the classes, it is clear that the difference between them lies in the structure of the supports.
It may be necessary to dismantle the rear wheel in the following cases:
- there is damage to the rim;
- broken tire or deflated tube;
- complete wheel wear.
For disassembly and subsequent assembly of the rear wheel of a bicycle with your own hands, in addition to traditional open-end wrenches, you will also need special tools:
- a puller for the type of cassette that is installed on a bicycle (for example, the mechanism of cassettes of the Stealth model and KhVZ road vehicles has a completely different design, therefore, suitable types of pullers are needed);
- whip. a cassette fixing device, consisting of a lever with pieces of a bicycle chain attached to it;
- a spoke wrench (it is desirable that it has at least three slot sizes, which will allow you to capture even old knitting needles with a knocked-down square of heads);
- special spoons for tire bead.
Advanced cyclists can use the repair stand to work in a natural pose.
Puller Whip Spoke Wrench Bicycle Mounts
How to properly disassemble, clean and lubricate the rear hub
Immediately remember one truth: any service is recommended to be carried out with a snagged sleeve. Otherwise, the chances of assembling the wheel correctly and quickly are unlikely to work. this can only be done by a person who is already experienced in servicing bicycles.
Step-by-step instructions for maintaining the rear bicycle hub:
- Remove the cassette from the axle using a whip and a puller.
- Opening the retaining ring.
- We remove all bearings and washers. Note:the sleeve can be on industrial bearings and bulk bearings, but in any case, it is very important to remember their original location in the sleeve. This rule must be observed when removing the washers.
- We carry out a careful inspection of the bearings. if they are damaged, this means the need to replace them with new parts.
- We take out the axle. it does not understand.
- We clean the body of the rear hub of the bicycle from dirt. All internal cavities must be wiped with a dry cloth.
- When installing back, each part is thoroughly lubricated, special attention should be paid to the bearings during this process.
- The last step is to install the stopper and tighten the fastening nut. It is not necessary to apply great efforts to tighten, as this can result in a problem of free wheel rotation.
Of course, everything looks quite easy and simple, but there are a lot of nuances in servicing the rear hub of a bicycle. they must be known and taken into account in the process of work:
- Firstly, the direct disassembly of the bushing should be started only after the cassette has been removed. over, the sleeve is disassembled from the opposite side and, as a rule, it is on the left. The locknut, if any, is unscrewed with a 15 mm wrench, then the stopper is removed (again, if any).
- Secondly, you need to be extremely careful when removing washers and rings. they will need to be laid out on a pre-prepared sheet of paper in the exact order, if this moment is overlooked, the assembly of the rear bicycle hub after cleaning and lubricating it can turn into real torment.
- Thirdly, after twisting the housing of the rear hub, its axis will begin to give in. just at this moment the bearings will appear. And again, you need to be extremely careful when removing the bearings. the parts are small and easy to lose. We remove each bearing with a knitting needle or tweezers, carefully wipe it with a rag soaked in kerosene or gasoline, and put it aside. Just in the process of wiping, the bearings must be carefully inspected for damage, and if there are any, then the part must be replaced.
Note: in the articles and instructions for servicing the rear hub of a bicycle, you can find a recommendation to use acetone to wipe bearings. this is permissible, but it should be borne in mind that the aroma from such a product will not be the most pleasant, and acetone can corrode the skin on the fingers. And one more thing. many “kulibins” in order not to lose small bearings use a magnet. in no case should this be done! The fact is that the bearing is magnetized and during the operation of the bicycle, iron dust is attracted to these small parts. the fact that the hub will soon become unusable can be predicted with confidence.
It is highly undesirable to confuse the left and right parts when disassembling / assembling the rear hub of a bicycle. this can lead to wheel play. If at least one ball is lost, then you will have to carry out a full replacement of the bearings. Sometimes, when opening the bushing near the axle, you can observe iron “dust”. this means that the bearings are completely worn out, they must be completely replaced.
How To Remove The Rear Wheel On Your Mountain Bike | Basic MTB Maintenance
Installing the rear wheel
To return the rear wheel to its place, it is necessary to install it in the fork and put a chain on one of the sprockets. Now you need to center the position of the element on the bike so that it is between the stays of both the upper and lower parts of the rear fork of the frame and looks strictly in the middle of the pedal axle carriage. Holding the wheel in this position, you need to fix it in the fork with standard nuts or an eccentric. It is important not to forget to restore the tension on the brake cable and place the chain on the drive sprocket. After installation, it is advisable to make sure of the correctness of the actions performed, to conduct a test drive. In the process, it is necessary to trace how the bike behaves after repair.
Maintenance and diagnostics of the rear wheel of a high-speed bicycle are mandatory procedures to maintain the serviceability of the mechanisms and long-term operation of the vehicle. Novice users will have more difficulty, but you can always use the instructions and read the advice of experienced craftsmen. Having completed the repair work on your own, it will be possible to save the family budget.
Main constituent parts
The rear wheel of a speed bike consists of the following parts:
Removing the front wheel from the fork
Removing a wheel is the simplest maintenance procedure for your bike. This is done very simply:
How To Remove The Rear Wheel of a Bicycle
- Turn the bike upside down.
- Release the rim brake, remove the caliper from the disc.
- Loosen the fasteners from the fork dropouts.
- Remove the wheel axle from the mountings.
On dropouts, the mount is nut and eccentric. In the first case, you will need two 15 mm wrenches. we hold the nut with one, and gently twist the other on the opposite side. With the eccentric, everything is easier. loosen the retaining nut and fold the clamping lever.
- replacement of tubes / tires;
- tightening / loosening of the spokes;
- bulkhead bushing;
- rim painting.
Installing the front wheel on the fork is done in reverse order.
The device and installation of the front wheel on a bicycle
The front wheel of a bicycle is a driving unit, without which it is impossible to imagine a bike, perhaps a unicycle. The driven wheel, synchronized with the fork, is responsible for the trajectory of the bike and, to a greater extent, the rolling speed. Unlike the rear wheel, the front wheel is simpler in design, but also requires timely maintenance.
A bike, like a car, needs regular maintenance, and the front wheel is one such important component that should not be neglected. Let’s give him a little attention!
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.
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.
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.
Bulkhead bushing, rim alignment, tube and tire replacement
The technical condition of the bike directly depends on the serviceability of all its components, including the front wheel. There are not so many problems with him, but they visit regularly:
- wear of bushing components, production of lubricant;
- curvature of the rim. “figure eight”;
- chamber breakdowns, tire cracking.
The hub provides a fixed axle attachment to the dropouts and uniform, unhindered wheel rotation. Insufficient lubrication causes increased bearing friction and, as a result, rapid wear. Symptoms. the wheel is loose, pronounced backlash, difficult rotation, crunching.
How To Remove And Replace Your Mountain Bike Wheels | MTB Maintenance
So, how to disassemble the bushing: 1. Remove the axle from the dropouts (see above).
Loosen the retaining sleeve nut. To do this, you need two 17 mm keys. fix the nut firmly on the right with one, twist the other counterclockwise on the left.
Screw the cone. For the hookup, you will need a key for 14, then it can be easily twisted by hand.
Pull out the axle from the opposite side. Carefully remove the left bearing from the housing cavity and pull the right one off the cone.
Inspect everything carefully, especially the bearings. Damaged parts must be replaced with new ones.
- Blow dirt out of an empty case.
- Using a narrow brush or cotton swab, apply a thin layer of lubricant to the inner walls of the bushing.
- Wipe the axle, cones and bearings with kerosene and let dry (if installing the same components).
- Lubricate the axle, bearings and tapers on the inner sides, which are in contact with the bearings. We do not regret lubrication on bearings: the more, the better. Gently wipe off excess with a clean cloth.
- Put the right bearing on the corresponding cone with the side as it stood before.
- Slide the axle into the bushing and install the left bearing on it.
- Screw in the cone carefully. Its surface should touch, but not pinch the bearing.
- Tighten bushing with nut.
- Place the wheel on the dropouts and fix.
We check the work of the bushing. we spin the wheel with force. If everything on the hub bulkhead has been done correctly, the wheel will spin easily and soundlessly. If the rotation is difficult or the bushing “moves” along the axis, it is necessary to loosen or tighten the left cone. Perhaps, for an accurate result, adjustment will be required several times, the main thing here is not to rush.
Eights are the most annoying wheel problem. It arises equally from the front and from the back. The front eight delivers less discomfort than the rear, but still, driving on a crooked wheel is not high. Consider how to quickly fix defects in a bicycle rim. To work, you need a universal spoke wrench, it looks like this:
Repair of the figure eight is done as follows:
- Determine the maximum wheel bulge. In this area, pull the needle at an angle that is a multiple of 1 turn.
- Loosen the two knitting needles at the edges at an angle, half the amount at which the central knitting needle was pulled.
- Pull the next outer needles to an angle half the size, by which those two needles were weakened.
And so on, it all depends on the amount of curvature. The picture shows a diagram of the elimination of a 7-spoke eight.
If the curvature is between the knitting needles, do this:
Replacing the chambers is easier than repairing rim defects, but also more often required. In order to properly and easily remove and install the tire, it is advisable to use special plastic assemblies.
- Remove the wheel from the fork mountings.
- Bleed air from the chamber (if we only change the tire).
- Unscrew the protective cap from the nipple and push it down slightly.
- On the opposite side, hook the tire bead with two assemblies.
- With the third assembly, hook the bead on the sides until the tire comes off the rim. Now you can get the camera.
- Pump up the camera a little so that it straightens.
- Place the camera in the tire.
- Select the correct direction of the tire using the arrow.
- Insert the nipple into the hole in the rim.
- Push the tire beads into the rim from the nipple side to the opposite end. When pushing becomes difficult, use editors.
- Pull the nipple tube upward (for Schrader).
- Check that the beads are completely in the rim and put the wheel on the bike.
The front wheel on a bicycle is a simple unit that you can self-service at home with your own hands: disassemble and assemble the hub, change the tire and eliminate distortions on the rim. Serious problems. broken spokes, cracking of the hub body. will require the help of a specialist.