Bicycle Rear Wheel Hub
The rear wheel hub of a bicycle is one of the most complex and expensive mechanisms on a bicycle. It is the rear hub that raises the most questions for novice cyclists. And its repair or maintenance is generally like a bad dream.
The quality of the bushings determines how much effort you will spend to overcome a certain distance, in other words, the speed of the bike. The rear hub is subjected to much more stress than the front, which dictates the need to make it more massive. In addition, if the front hub has only one function (free wheel rotation), then the rear hub is additionally assigned functions. torque transmission, pedal-free travel, braking functions, and even sometimes internal gear shifting systems (planetary hubs).
There are a lot of companies that produce bicycle hubs and it makes no sense to list them all. It is worth noting Shimano rear hubs, in Russia these are the most common hubs, due to their high quality and wide price range.
Like the front hubs, the rear hubs may differ in materials of manufacture, purpose, production technology, weight and strength. But the rear hubs have their own differences inherent only in them. Which ones will be discussed below.
Rear Hub Types
By application, the rear bushings can be used for road bikes, high-speed bikes (mountain, touring and road). Road bikes are usually fitted with single-sprocket hubs and a freewheel mechanism. Also, bushings for road workers are equipped with a drum brake, i.e. hub with foot brake. The rear hubs for sports bikes do not have a brake mechanism, but they have a free wheeling system. In addition, the sports rear hubs are divided into cassette and ratchet.
Rear hub materials and manufacturing technologies
The rear hubs do not differ from the front hubs in manufacturing methods and materials. Bushings are produced by casting, turning or stamping. Cast bushings are the cheapest to manufacture, but also the least durable and heaviest. The most optimal metal for the bushings is an aluminum alloy. Bushings for the simplest and cheapest bicycles are made from steel. The lightest and most durable bushings are obtained from titanium alloy, but they are so expensive that they are used only in professional sports bikes.
Speed bike rear hub device
Rear hub device for sport and mountain bikes
The hub device of the rear wheel of a high-speed bicycle provides for a set of driven stars through which torque is transmitted to the wheel. There are two types of chainring set. cassette and ratchet. If the hub is designed for a ratchet, then the drum (nut) is located outside the hub and integrated into the set of stars. The ratchet itself is attached to the fork with a special thread. If the sleeve is for the cassette, then the drum is located on the sleeve itself and is attached to it using a special hollow bolt (see diagram). The cassette, in turn, is attached to the drum through a spline connection and secured with a special nut.
Rear ratchet thread hub
Splined and threaded hubs, cassette and ratchet
It is worth adding about the mounting of the disc brake rotor. Here, like the front hubs, there are two standards. CenterLock and 6 Bolt. The CL standard provides for spline fastening and tightening with a special nut. This standard is patented by Shimano. The six-bolt mount is more popular and is used by all rear hub and brake manufacturers.
Rear hub for six-bolt rotor mounting
Rear hub with CenterLock for rotor
6-bolt rotor with CL mount
Rear hubs with brake
Most single-speed bikes, whether road or kids, have a rear hub with built-in brakes and free-wheeling pedals. These bushings perform several of the following functions:
- Transfer of torque from the driving sprocket of the connecting rods to the driven sprocket of the rear hub and, accordingly, to the wheel itself.
- Free wheeling relative to the driven sprocket. As soon as the driven sprocket stops, the wheel continues to rotate, regardless of the bicycle pedals.
- The built-in braking mechanism allows you to brake by pedaling in the opposite direction. The essence is the same as in car drum brakes with inner pads.
The most common brake bushings are of the Torpedo type. These bushings were found on most Soviet bicycles and are still used today in the road bike industry. On the oldest Soviet and some imported bicycles of the beginning of the last century, Idi type bushings were installed. Also in Soviet times, domestic bushings with the self-explanatory name Motherland were developed. The last two types are almost never found at the present time. Therefore, we will consider in more detail the device of only Torpedo bushings.
Diagram of the rear brake hub type Torpedo
Based on the above diagram, let’s look at how the processes occur inside the rear hub.
- Working stroke. while turning the pedals, the drive cone, rotating with its protrusions, shifts the drive rollers up, thereby wedging the hub body, thereby rotating the wheel.
- Free play. as soon as the drive cone stops rotating, the body squeezes the drive rollers into the recesses between the lugs, thanks to this process, the connection between the drive cone and the body is lost. Loss of communication allows the wheel to rotate freely relative to the pedals.
- Braking. when the cyclist starts to push the pedal back, the drive cone begins to rotate in the opposite direction and with oblique lugs rotates the brake cone due to friction. The brake rollers engage in the brake drum grooves and the brake cone is pushed into the drum. The drum is moved apart by cones on both sides, pressed against the hub body and brakes the wheel.
Torpedo type provides the best braking option. The stronger the effort on the pedal, the stronger the braking. this ensures smooth braking.
How to lubricate
The ideal option is a Teflon compound. For example, Finish Line Premium Grease: very slippery and viscous. However, Teflon can be replaced with the usual Litol-24 or the consistency for the CV joints of the car.
What definitely doesn’t work is any liquid mixture:
- Bicycle chain maintenance compound.
- Car engine or transmission oil.
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How to apply lubricant
The goal is to lubricate balls, cones and cups. This can be done as quickly and efficiently as possible using the following technology:
- Lubricate the cup with your finger.
- Put the balls into the cup using medical tweezers, observing the intended purpose of the groups sorted during disassembly.
- Apply a thin layer of lubricant over the balls.
- Repeat steps 1-3 for the second side.
- Put the boot on the locked cone located on the side of the cassette (relevant only for the rear bushings).
- Apply a thin layer of grease to the beveled surface of both cone nuts.
There should not be a lot of lubricant at the contact points. This statement is relevant only because excess grease is squeezed out through the anthers, and it intensively begins to collect dust. You can estimate the sufficient filling level from the photo. There are usually no problems with the installation of balls. They adhere well to the lubricant, which is already in the cup according to paragraph 1 of the technological instructions.
It is customary to lightly coat the thread on the axle and the ends of the nuts with a compound that was used to treat rubbing surfaces. This activity is designed to minimize oxidation of metals and the formation of rust at the interface of detachable parts.
Industrial bearing bushing
Many people dislike bushings on flare nuts because of the difficulties associated with adjusting them after assembly. In this regard, a worn out support is often changed to a version with slips.
The advantages of the industrial bearing design include easy maintenance. There is no need to adjust anything here: the bearing fits snugly in the cup and on the axle, there are no flare nuts. In theory, such a wheel should not have any backlash, which is demonstrated by expensive specimens. In cheaper models, low-grade rolling bearings are used, in which the clearance is observed even from the packaging.
For your information. Backlash in the bushings on a slip is eliminated only by replacing the bearings. The latter are difficult to remove, therefore, when critical gaps appear, the mechanism is replaced as an assembly.
How to disassemble
Initially, it is necessary to provide unhindered access to the flare nuts. For this, they usually remove:
- Disc brake rotor. Not in all cases can be dismantled. Make sure that the bolts do not interfere with the installation and rotation of the tapered (thin) wrench. If there is a gap between the key and the disc, it is not necessary to remove the latter. There are situations when the tool fits freely in the back, and on the front bushing it is impossible to do without removing the rotor.
- Cassette / ratchet. It is imperative to remove, otherwise you cannot reach the second cone, and the axle cannot be removed. The process of dismantling the cassette is shown in the photo.
When the flare nuts are accessible, you can unlock one of them. In this case, it is important to observe two rules:
- Only one side is allowed to unlock! The second must be locked to failure even from the factory and it is forbidden to touch it.
- You can only unlock the cone located on the side of the rotor mounting (if there is no disc brake, then focus on the side opposite to the cassette). The fact is that the cone nut, weakened from the side of the sprockets, self-tightens upon impacts or collisions with an obstacle, which is why the free wheeling of the sleeve is disturbed. And this reduces the resource and worsens the roll-forward. This does not happen with the left side, since there the cone-nut tends to unscrew, and the lock nut and eccentric prevent this. In total, such a scheme maintains a balance and you can choose a gap without prejudice to the roll.
The deconstructing procedure is shown in the photographic material. A thin cone wrench adheres to a cone-nut, and with another wrench (for convenience, it is advisable to take a more massive tool) unscrew the locknut. After that, the threaded parts are completely twisted, and the axle is removed. Next, you need to remove the anthers and remove the balls from the cups.
Attention! When disassembling, note the order in which the components are located. The ideal option is to take a photo of the placement of anthers, nuts and washers on fresh tracks, as shown in the image.
When dismantling the balls from the seats, it is important to separate them into two groups. Those on the right must be folded in one place, those on the left in another. Do not mix or confuse these groups with each other, otherwise, after assembling the perfect reel without backlash, you will not get.
Important! When removing the axle on the front wheel of a bicycle without disc brakes, mark the side of the non-rolled cone on the tire. Another landmark on this type of bike is the direction of rotation of the rubber shown on the side.
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The most common type. Particularly in the Shimano range, you won’t find knot on the slip. The company explains this by the fact that the design based on cone-nuts has better reel. Configuration elements of such a product are shown in the figure:
In the technology of bulkheads on cones, three stages should be distinguished: disassembly, lubrication and assembly and adjustment. A tool is needed at every stage. Complete cassette hub kit shown on
Recommendation. If you plan to service the bike from A to Z yourself, then a suitcase with tools from X-Tools will be very useful. In particular, it has a chain squeeze and even a spare head. And this, by the way, is an indispensable device not only at home, but also on a hike. You can buy a set at a democratic price at ChainReactionCycles.
The plug is only needed for hydraulics. In the methodology describing how to adjust the hydraulic disc brakes on a bicycle, we have already discussed the consequences of accidentally pressing the brake lever in the absence of a rotor in the hydraulic circuit. For a bushing mechanism with a ratchet, a whip is not needed, and the mandrel of the wrench is replaced with an adapter from the slots for an open-end or box wrench. Externally, the adapter sleeve looks like a mandrel for removing the cassette, which is present in the photo with the tool.
Cleaning and lubrication
It is necessary to clean the balls and cups in contact with them, cone-nuts, axle. In a sleeve with good dust protection, the lubricant is usually clean, so cleaning can be carried out without chemicals. with an ordinary clean rag. If dirt is present, use one of the degreasers we have recommended for cleaning the chain in the material, how to clean old bicycle chain grease at home.
How to loop through the rear and front hubs on a speed bike
Bulkhead of the bushing, whether it be rear or front, is an event that can be either forced, due to water entering the bushing, or routine. Its purpose is for the most part preventive. to change the lubricant and, if necessary, replace some components. If we are talking about a classic cone bike, then it can be a worn ball or a cone. However, on high-speed bicycles, there is another type of support that also needs maintenance.
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thoughts on “ How to Assemble Chinese Bicycle Rear Wheel Worm Hub! ”
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In my childhood, I disassembled grease for half a day, I suffered and could not collect
how do you collect through the back seat…. first, an axle with a bearing is placed on the side of the larger diameter of the rim and then everything else, otherwise you throw in the pads and then you aim horseradish you will understand how. you yourself do not do the right thing and teach people.
There are two carriages inside bushings of different sizes. The one that is smaller and thicker is installed on the side of the sprocket, and the larger and thinner one is on the side of the brake. Otherwise, you don’t want to …… collect it. It is better not to unscrew the locked brake lever, but if it is unscrewed, then it is necessary to tighten it well, otherwise problems.
It seems to me that the minus of the ill-conceived design is that this spring in the drum is always spinning and rubbing It would be necessary to go there, in theory, another mini bearing
I was 8 years old and I didn’t collect it at all.
And if you do not put the brake pads, the brakes will not?
Hello, but how to make it so that there is no brake? What exactly needs to be removed from there?
tell me why the asterisk does not rotate and wedges? what could be the reason? thanks in advance.
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Thank you very much Friend. I looked and assembled it in 3 minutes, and for half a day I tried to make out this rebus
Thanks without this video, I would not have collected them
Well, you handsome two days could not collect it. thank you buddy.
Thank you very much. I put it the other way around)))
It’s good that you tube eats, otherwise I’m worn out village den thanks
Great video ! Here’s just how to correctly put the bearing in question for 3 minutes 30 seconds balls down or up?
I bought my offspring two bike units of Chinese origin a couple of years ago, and now it’s time to get into the rear hub. At first I disassembled one wheel, naturally everything fell down I thought it was good that there were two of them, rear wheels, now in the second I will look what and how For three days I probably watched what and how, until I found your vidos Thank you, my friend, for the hint.