How to make dropouts for a bicycle. Hellride Educational: MTB Frame Dropouts. The main functions of various plugs include

In this report I will write about converting a regular road frame into a regular road frame :), but with the ability to tension the chain.
The materials below will contain violence and scenes of a sexual nature. Please keep highway drivers, Cannondale fans and ASUS video card fans away from the screens.

The idea of converting a frame from road to track has been in the air for a long time, and with the rise in the explosive growth of prices for track frames, it is inflated even more.

I came across the CAAD3 frameset on the forum, and if you take into account everything that came with it, the frame came out at a record price and the process began.

First of all, I inspected the frame and was pleased to note that most of the road trinkets were simply removed with screws. Here are the cable stops and the chainstay guide.

The native cock of such frames is specific and is also very convenient for alteration. I recognized the rear brake cable stops that were on the top tube as dangerous and carefully removed them with a file.

Instead of a permanent remodel, I opted for the option of removing my molding and putting the road bike back together.

Everything is more or less clear from the diagram

The idea was to cut a plate of the desired shape, 3mm thick, and another one, 3mm thick + dropout thickness... i.e. about 9mm. Next, in a thick plate, use a small hand mill to carve a notch in the shape of the dropout on the frame.

I know little how to plan, and even less I know how to wait, so the material used was whatever came to hand, namely two radiators from video cards. I was still a little afraid that there would be cavities with gases in them =), but it all turned out to be marketing. The material is soft enough to handle, but not plasticine either. Bending one radiator fin even with pliers is not as easy as it seems.

Everything was intended as a temporary option, but we know that... There is nothing more permanent than temporary.

In the final version there are no creepy nuts :).

This is the left one.

The sawed-off dropout is fully suitable for installing a wheel in the highway version. A few extra holes won't hurt it.

Well, here is the final version after 400 km. The placement of the screws seems chaotic, but it is dictated by the shape of the drops.

The flight is wonderful. I don't regret anything. I will also redo the next frame (and it 100% will happen), but avoiding those stones that I hit my head on the first time.

Roughly speaking (damn rudely, even a little boorishly), frame dropouts are the holes/slots into which the rear hub axle is inserted. In order for the hub to fit the frame, the standard of the dropouts must match the standard of the hub. We are interested in the distance between the holes in the frame and their diameter. Below we will list the existing dropout standards, tell you how they differ and where they are found.

135x10mm- the classic and most widespread standard several years ago. Dropouts are slots in the frame. There are vertical and horizontal.
Horizontal ones are usually made on freestyle frames and allow you to change chain tension by adjusting the position of the axle. It is better to use axial bushings with them rather than eccentrics.
With vertical dropouts, the position for the hub axis is unchanged. Bushings for both eccentric (QR) and solid 10mm axles are suitable here.
In racing disciplines, the 135x10mm standard is gradually being replaced by more durable and/or convenient analogues.
On recreational bikes and freestyle hardtails, 135x10mm is most common and has not yet been replaced.

135x12mm- a more durable mounting option than 135x10 due to the thick axle. The dropout consists of through holes in the frame. One of them is threaded, for the axles. The bushing for this dropout has a plug-in 12mm axle with a thread on one end and a key/hex or lever on the other. All dropouts for 12mm axles have a similar structure.
Now 135x12mm has almost everywhere been replaced by the 142x12mm standard.

142x12mm- the most popular standard of bicycle hubs today for racing and near-racing disciplines: CC, trail, AM, enduro and so on. The device is the same as that of 135x12, but the bushing is wider and the axle is longer.

148x12mm (boost)- a new standard developed for 27.5+ wheels and wheels.
The advantage over the above is that the distance between the bushing flanges is greater. This allows you to increase the lateral rigidity of the wheels.

150x12mm- classic standard for downhill wheels. The distance between the flanges is larger, the wheel is stiffer. There are also standards 157x12mm (DH bikes) and 165x12mm (old DH bikes and/or fats).

Many cyclists are outraged by such an abundance of “unnecessary” standards. A survey was conducted on the website whatswrongwithmtbcom - what characteristics would a bicycle have on an imaginary planet where every piece of hardware has the same standard. 1000 people were surveyed.

The top four results look like this:
462 people (47%) for 142x12
147 people (15%) for 135x10
131 people (13%) for 135x12
129 people (13%) for 150x12

Obviously, most cyclists could get by with one or two of the standards, but the reality looks different. That's why we've collected all the standards here so you know about them and don't get scared when you see these numbers in the description of your new frame or hub.

First we need to make it clear that there is confusion between these two concepts.

The eccentric is just a way to tighten the nut. I won’t describe the mechanism, I think everything has been presented. And in relation to bushings, this is a method of fixing the bushing in the dropouts of the frame or fork, or fixing the axle. But it also includes the meaning of an axis, which is also not entirely true. Let's figure out what's what.

These are the axles of the front bushings

Integrated. So to speak, an axle with an outer diameter of 9mm and an inner diameter of 5mm (first picture). A 5mm tie is inserted into it, which everyone calls an eccentric in the English version, quick release (QR). By the way, there is also an option for a hexagon (second picture), without an eccentric. Designed for forks with open dropouts.

photo 1 photo 2

Internal. A bushing with an internal axle with a diameter of 12mm, the ends are machined so as to fit into open 9mm dropouts. Fastened with 5mm bolts or eccentric.

Example SUN Ringle:

Axleless. Such a bushing has a hole of 9mm, 15mm or 20mm in diameter, into which a 9mm, 15mm or 20mm axle is inserted, respectively.

Hexagon or quick release. For example, 9mm eccentric, 9mm RWS thru bolt from DT Swiss

or with a 20mm Maxle axle from RockShox. In the English version 9/15/20mm thru axel.

The 9mm axle can be mounted to the same open dropout forks as the first two options. And for 15mm and 20mm, you already need so-called forks for a 15mm axle

and 20mm:
There are also forks for 9mm axles, for example, some Marzochi:

15mm axle on FOX fork

Rear hub axles

Again, an integrated hollow axle with an outer diameter of 10mm, an inner diameter of 5mm (http://www.chainreactioncycles.com/Images/Models/Original/8200.jpg), under the same 5mm eccentric (QR) or hexagon (http:// www.chainreactioncycles.com/Images/Models/Original/26621-2.jpg), which acts as a fastener.
Hub for 10mm bolts (http://www.chainreactioncycles.com/Images/Models/Original/33673-2.Jpg): there is an axle inside, but it does not extend beyond the edges of the hub, as in the case of an eccentric, but has a thread, into which a bolt with a diameter of 10 mm is screwed in on the right and left. In English it can sound like bolt up or bolt on.
Bushing for 10mm axle (http://www.chainreactioncycles.com/Images/Models/Original/28787.jpg). Hollow inside, without its own axis, a 10mm axis is inserted into them, which serves as a lock. It is tightened either with a nut or, again, with an eccentric (as an option RWS thru bolt (http://www.chainreactioncycles.com/Images/Models/Original/21670.jpg) from DT). In the English version, 10mm thru bolt axel (the word bolt may be missing).
For 12mm axle (http://www.chainreactioncycles.com/Images/Models/Full/7568.jpg). Similar to the previous option, only the axle diameter is 12mm. Again, there is a quick release option, such as the Maxle (http://www.chainreactioncycles.com/Images/Models/Original/27736.jpg) from RockShox. English version - 12mm thru axel.
Under 10mm (http://www.rohloff.de/typo3temp/pics/fc872e0176.png), 12mm (http://www.chainreactioncycles.com/Images/Models/Original/12151.jpg) or 14mm (http: //www.chainreactioncycles.com/Images/Models/Original/34011.jpg) nuts. The axle is long and comes out of the dropouts; nuts are screwed onto it, which secure the bushing.

The bushings also differ in width, that is, for different distances between the dropouts.
Front bushings for eccentric, 9mm and 15mm axles - 100mm, for 20mm axles - 110mm.
Rear: for an eccentric - 135mm, for a 10mm axle and bolts, as well as a 12mm axle, there are both 135mm and 150mm. For 14mm I know only for 135mm, moreover, single speed (without the possibility of installing a cassette).

As for when the axle is stronger - in theory, always, since eccentric axles are usually not for the entire dropout, but for half. And the axle also better fixes the bushing and increases the torsional rigidity of the fork/rear triangle - this is already a fact.

February 25, 2016

Bicycle frame- This is a fundamental component of any bicycle. Such important features as the further purpose of the “bike”, riding style, convenience, comfort and of course safety depend on it. The strength of a bicycle also directly depends on the bicycle frame. Today there are many different options for bicycle frames, they differ in material, geometry and other important details. To understand all this, it’s enough just to look at a certain average version of the frame and understand what parts it consists of and what the individual components are correctly called.

Bike frame components

Any “classic” bicycle frame is structurally composed of tubes, which can be made of various materials, combinations of materials, alloys or composites. To obtain the required (balanced) ratio of strength/flexibility characteristics in each specific case, combined materials are often used. Pipes can be of any shape and cross-section, with a square or round profile.

The frame design that is familiar to everyone is two triangles, front and rear (these triangles can be imagined virtually if you also mentally examine the frame from the side).
They can have any shape, not necessarily a perfectly even geometric shape, but they still retain this name. The final look depends on the imagination and intentions of the manufacturer or the “designer” of the frame, if he was involved during its creation. Although anterior triangle can be considered as such very conditionally (since it consists of 4 pipes, and not 3), the following elements can be distinguished in its structure: headset, head tube, top tube and seat tube.

Posterior triangle comprises: seat tube, seat stays and chain stays. At the bottom of the frame, where the main tube meets the rear triangle and meets the seat tube, there is a

The lower rear stays go into brackets for mounting the rear wheel, or they are also called dropouts. The hind feathers also include brake system mounts v-brake, but nowadays almost all of them are mounted on disc brakes.

The frame design sometimes differs from the “classic” one due to various tricks from the manufacturers and the intended purpose of the bicycle. But even in this case, the basic principle and names of the frame elements are retained, even if their shape undergoes changes.

To ensure the immediate functionality of the future “bike” and all its systems, the bicycle frame includes in its design individual elements that serve to install specific components. Let's take a closer look at these frame elements:

IN steering glass is installed steering column (headset), V hole for carriage- installed accordingly bottom bracket, and in seat tube hole is installed seatpost together with saddle.

Rear wheel hub mounting brackets or "dropouts" can be vertical, horizontal or adjustable.
Vertical dropouts the most convenient and easy to use - they allow you to quickly put the wheel in place, and do it as smoothly as possible (chain tension in this case is provided by the rear gear selector, separate manual adjustment is not required).

Horizontal dropouts Nowadays they are used less and less due to the specificity of the design. With their help, the chain is tensioned, which is especially important for “singlespeed” (bicycles with one gear, without a rear derailleur). Another use case could be in tandem with a planetary hub. However, with enough force, the wheel axle can move. To prevent this, there are special axle clamps.

Adjustable dropouts come in a wide variety of variations: with or without holes for mounting the rear derailleur. They allow, as the name suggests, the “base” of the bicycle to be flexibly adjusted within small limits. These dropouts are easy to change and the bike can easily be converted to a single speed.

Modern bicycle frames also often include additional structural elements for attaching accessories and other add-ons. devices. On most frames you can see holes for installing a bottle cage, and fasteners for brake cables and gearshift systems.
The latter are often replaced with holes on high-end frames to allow the cable jackets to pass through inside, thereby improving the aesthetic appearance of the bike, increasing comfort and reducing the unpleasant effect of chafing on the jacket or frame. Some frames come with additional accessories holes for fixing wings, which is usually typical for road and touring bikes.

Let's take a closer look at some frame elements and try to understand how compatible components are selected for each specific frame and what differences there are:

Steering glasses (headset) on the frame they can be regular or integrated. Taking these features into account, the steering column is selected for the glass.

Conventional steering glasses They are much more common, they are more often found on sale and do not involve any complex features. The easiest way to find and select a steering column for such steering glasses is to do this taking into account your own riding style preferences.

Integrated steering columns are considered a more professional and thoughtful engineering solution, easy to install and require virtually no maintenance, but can damage the frame in some cases (or lead to expensive repairs).

You can read more about steering columns and compatible steering columns in.

Carriage unit frame consists of glasses, in which it is installed carriage. This glass varies in length and type of thread, depending on the features of the frame.

There are three types of frame threads:

English thread (BSW, 1.37 in x 24 TPI);

Italian thread (BSC, ITA 36 mm x 24 TPI);

French/Swiss thread (M35×1);

There are also glasses with integrated systems. In them, bearings with cups are pressed directly into the frame, and the axle remains the central element. Such systems are called "Pressfit" and they are gaining popularity in the design of professional frames recently. There are also eccentric carriages that rotate in their seat and feature automatic chain tensioning functionality. The latter are used extremely rarely; they are an alternative to a drive with a front gear shift system.

Seat tube frame is equipped seat clamp. It can be integrated (only on older frame models) or external.
Depending on the diameter of the seat tube, clamps come in the following most common standards: 27.2 mm; 30 mm; 31.8 mm; 34.9 mm;

External seatpost clamps can be:

Eccentric- clamped without tools by hand, using physical force. Convenient, understandable and easy to use for everyone, do not require additional tools.
Bolted- fix the seatpost with a bolt, usually a hexagon. Less convenient, they require a tool to adjust the tightening force, but they are more reliable.

The frame design can also vary significantly in the presence or absence of rear suspension and its varieties.
As a rule, in such cases, the bicycle frame will have a detachable rear triangle and some kind of structure (individual) on which the shock absorber itself will be attached.

Frame geometry

A bicycle frame and its intended purpose largely depend on geometry, the most significant and significant parameter for this product. The geometry of the frame is determined by the length of the pipes and the angles at which they are connected. The most significant and determining parameters of the frame geometry can be noted: the angle of the head tube, the angle of the seat tube, the length of the top tube and the length of the seat tube.

Analyzing the frame geometry in detail, we should highlight some characteristic frame dimensions, which are often indicated by one or another manufacturer. These dimensions are quite significant when choosing, especially taking into account the intended riding discipline:

Saddle height- distance from the center of the carriage to the middle of the saddle
Stack- vertical distance from the center of the carriage to the top point of the steering column
Reach- horizontal distance from the center of the carriage to the top point of the steering column
Bottom braket drop (carriage indentation)- the distance that determines how low the center of the carriage is relative to the center of the rear bushing
Handlebar drop- the distance that expresses the vertical difference between the top of the saddle and the top of the handlebars
Saddle seatback- horizontal distance between the front of the saddle and the center of the carriage
Standover height (full height)- height from the ground to the top tube of the front triangle
Front center- distance from the center of the carriage to the center of the front bushing
Toe overlap- determines the distance from the rider’s foot on the pedal to the front wheel while turning the latter

The geometry of the frame plays a decisive and most important role in the behavior of the bicycle on the road, its stability, and the responsiveness of the steering wheel. It also determines the convenience and comfort of landing, affects the acceleration and braking characteristics, and the overall dynamics of the bicycle. You should pay close attention to these dimensions when choosing a frame to suit your individual needs and wishes. There are a number of the most important practical dimensions that should be taken into account first:

Top tube length. Measured from the center of the steering column to the center of the seatpost in a straight horizontal line. This parameter directly affects the stability and maneuverability of the bike. The higher the length, the more stable and responsive the bike will be.
Steering column angle. The angle between the steering tube and a straight vertical parallel line. A larger angle determines better maneuverability of the bike.
Seat tube angle. Determined by the inclination of the seat tube in relation to a straight parallel vertical line. This characteristic is responsible for the shift in the center of gravity, namely, it answers the question: “Does the center of gravity shift and how much when the cyclist sits in the saddle?” The bike’s predisposition to extreme elements and tricks depends on this, and also determines confident grip on the surface (if the angle is larger) or a greater predisposition for dynamic riding during high-speed pedaling (if the angle is smaller).
Wheelbase. The distance between the centers of the front and rear wheel hubs in a straight horizontal line. The longer the wheelbase, the more stable, maneuverable and stable the bike will be.
Length of the rear triangle chainstays. Measured from the center of the bottom bracket to the center of the rear wheel hub. The shorter the length, the more reliable and durable the frame and the better the bike’s grip on the surface, and the more responsive the bike is when steering and other high-speed maneuvers.
Ground clearance/height to carriage assembly. The distance between the lowest point of the bicycle (bottom bracket) and the ground. Affects maneuverability and speed. The higher the height, the more confident and stable the bike is off-road, and the less likely it is to catch the frame on any unevenness or obstacles. But along with this comes a big loss of speed and dynamics.
Stem length. Measured from the center of the steering column to the handlebars (stem). Significantly affects maneuverability and ease of landing.

Overall frame size is traditionally measured along the seat tube, from the center of the bottom bracket, to the center of the top tube (where it intersects/meets the seatpost). So the “size” of the frame is determined and the bike in general. However, there are other measurement methods.

The size of the frame is directly related to the height of the person who
intends to ride a bicycle assembled on the basis of this frame. This relationship can be roughly represented as follows: The XS size frame is designed for a height of 152-162 cm; frame size S for height 162-172 cm; frame size M for height 172-182 cm; frame size L for height 182-192 cm; frame size XL for height 192 and above;

It is customary to select a slightly smaller frame size for extreme riding disciplines in order to increase controllability and maneuverability for performing tricks and various jumping elements.

Frame materials

A bicycle frame can be made from various materials. Since the dawn of cycling, this has traditionally been steel, but frames can also be made of aluminum alloy, carbon fiber, titanium, thermoplastic, or even bamboo and wood. Each material provides a combination of its own unique characteristics and inherent disadvantages. Also recently, combinations of different materials (composites) are often used to achieve the necessary balance of low weight and high structural strength. When choosing a frame material, the following properties play an important role:

Density- the final weight of the frame depends on this parameter
Rigidity- has little effect on the transmission of pedaling energy and rider comfort. Determines the ability of the frame to deform without destruction.
Tensile strength or transverse strength- determine the force with which the material is deformed.
Tension/elasticity- determines how much the material must be deformed before it breaks.
Fatigue- determines the durability of the frame in the future of active use.

Brief advantages and disadvantages of the most common frame materials, making it easier to choose a frame for individual needs and riding style:

Steel frames. For the production of frames, chrome-molybdenum steel is currently most often used, which is distinguished by its excellent strength, reliability and endurance, as well as the invariably good elasticity of the material (the frame feels comfortable in motion as it “plays” a little, although thereby losing in the dynamics of movement) .
Frames made from this steel are fairly easy to repair if they break and are very durable due to their excellent fatigue characteristics. But the disadvantages of such frames are also very significant, including high weight compared to frames made of other materials (several kilograms for the same size) and susceptibility to corrosion. To combat corrosion, the frame is coated with a special compound, but if the paint and varnish coating is damaged, it can be very difficult to stop the development of corrosion. Consequently, such a frame is not so unpretentious and durability is negated by such problems. Of course, corrosion is not as severe as compared to a car body, for example, but a bicycle is quite capable of losing its presentation and reducing its strength over time. A bicycle frame made of steel is often chosen by lovers of tourism and quiet rides for a fairly balanced combination of characteristics, good comfort (which is important on long trips) and reasonable cost.
Titanium frames. The use of titanium in bicycle production is borrowed from aviation. But, despite the fact that titanium has a number of undeniable positive qualities, such as: increased specific strength and incredibly low weight (often lower than aluminum counterparts with greater strength), corrosion resistance, increased elasticity (titanium frames are considered one of the most comfortable) and excellent fatigue characteristics (and therefore durability), such frames have a number of significant disadvantages.
The complex technological process of manufacturing such a frame and the high cost are not always justified, as well as almost complete non-repairability in case of damage. Titanium frames most often become the choice of understanding professionals who have been involved in cycling for a long time and are willing to put up with the inflated price of this fundamental component.
Aluminum frames. More precisely, frames made of various aluminum alloys with impurities, since aluminum in its pure form is a fairly soft metal. Aluminum alloys are divided into series, so in the 7000 series an admixture of zinc is used, and in the 6000 series magnesium is added. Aluminum frames are the most common today and are in demand due to the ideal compromise in price, quality and set of characteristics.
These frames are practically not subject to corrosion, are characterized by low weight, but at the same time reduced elasticity and increased rigidity. In practice, they are less comfortable and not really designed for bicycles that are expected to travel long distances. It is believed that bicycles based on such frames are more maneuverable and responsive, with better acceleration dynamics. Aluminum frames are best suited for extreme disciplines. Among the disadvantages of this material, it is also worth noting its unsatisfactory fatigue characteristics. Recently, manufacturers are increasingly declaring a lifetime warranty on their aluminum frames. In the manufacture of aluminum frames, interesting, innovative technology is also sometimes used. hydroforming, which eliminates the presence of seams in the frame structure or reduces their number, making the final product more aesthetically attractive.
Carbon frames (carbon fiber). This frame is made of carbon fibers impregnated with special adhesive resins. This material is a classic composite. It has sufficient strength for a typical bicycle frame, but is burdened with a bunch of disadvantages, such as: an unusually complex manufacturing process and at the same time the highest cost of the frame (often unjustified), low impact strength of the material, and absolute non-repairability.
Such a frame is enough for a couple of years of active use, and the cost is many times higher than any analogues. Such frames are suitable for professional cyclist racers who chase every gram of excess weight so as not to lose performance. It is advisable to use such bicycles for racing competitions, keeping them in “preservation” in a warm room for the remaining time. The only worthy significant advantage of a carbon frame will be the lowest weight of the frame among other analogues, and also the fact that this material is simply not susceptible to corrosion.
Other rare materials practically never found in mass production.
Among them, aluminum alloys with rare impurities and various types of wood (including bamboo) can be distinguished.

In the manufacture of bicycle frames and individual pipes, manufacturers sometimes use "batting". This technology makes it possible to slightly reduce the final weight of the frame by using different wall thicknesses of the frame tube and at the same time varying the density of the material in different most loaded areas of the frame. Typically, such a frame is denser at the joints, which is determined by the necessary margin of safety at these points, taking into account the increased load on the unit. Batting can be double or triple.

steep slope

Singlespeed - a bike with one gear is popular in street and dirt. But thanks to some of its properties, it can also be convenient for cross-country in winter and in the off-season.

Of course, the first problem that needs to be solved before starting to assemble a singlespeed is what gear ratio to choose. General recommendations boil down to the fact that for driving in the city and on highways with not very hilly terrain, the ratio of the number of front sprocket teeth to the number of rear sprocket teeth should be 3 x 1. For hilly terrain and particularly difficult urban conditions, it is better to choose a smaller gear ratio - for example 2.5 x 1. For very rough terrain and off-road, the gear ratio 2 x 1 is best suited

The advantages of singlespeed are as follows:
- Less weight. The switches, shifters, cables with jackets, one or two front sprockets, and the cassette except for one sprocket are removed from the bike. This turns out to be quite a saving, especially if the equipment was not expensive.
- The system turns out to be more reliable. Due to the fact that the chain is relatively tightly tensioned, it almost never falls off. After any impact, you can be sure that in response to pressing the pedals, the bike will begin to accelerate, and not crunch.
- Cheaper. Even if you buy a special chain, sprockets and tensioner, it still costs less than a system with gears. This is if you buy new parts, and if you use dead ones, then it’s completely free, although with restrictions.
- Easier care. There is no need to clean off dirt and adjust switches so carefully. It’s easier to clean the chain then dirt and lubricate it. If you use dead components, then it is quite simple to add oil to the chain from time to time.
- And one more minor advantage. With one gear it is easier to navigate in a tense situation; you always know how hard to press the pedal.

Flaws:
- Poorly suited for rough terrain. Even if you use a bike only for street or dirt, it still becomes difficult to ride it from home to the riding area. And you can’t race cross-country at all - you’ll just kill your knees.
- In some cases, you will either not have enough speed, or you will have to press the pedals harder than usual. One pass, what can you do?

Singlespeed is usually made either on the basis of a frame with horizontal dropouts, or on a standard frame, with a special chain tensioner installed instead of the rear derailleur. In the case of horizontal dropouts, special stops are used that do not allow the wheel to warp. For dual-suspension systems, only the option with a tensioner installed in place of the rear derailleur is suitable, since the length of the rear stays changes when the suspension is in operation. However, there are frames with vertical dropouts that have an eccentric carriage unit, by turning which you can achieve normal chain tension. You should also remember that the planes of the front and rear sprockets must be at exactly the same distance from the central axis of the frame, otherwise the chain will constantly fly off, especially when shaking on uneven roads and when pedaling in the opposite direction.

Vertical dropouts
Vertical dropouts - with a groove located strictly vertically. In this case, there is no possibility to vary the position of the wheel, and even if the fastening is unreliable, the wheel axle will not change its position.
This type of dropout is mainly used in bikes with derailleur systems. Due to the fact that in this case it is impossible to regulate the chain tension by the position of the wheel, it is necessary to either use a speed switch with a tension system, or a separate external tensioner.

Horizontal and inclined dropouts
Horizontal dropouts allow you to vary the wheel position. This type of dropout is necessary for bicycles without a rear derailleur, since in this case the rear wheel axle must be movable to adjust the chain tension. When installing a wheel in horizontal dropouts, you need to be extremely careful and ensure that the bolts or eccentric are securely fastened to avoid subsequent distortion of the wheel due to chain tension.
Horizontal - usually on track frames. Inclined - on most singlespeeds. This is why dropouts need slope. Many non-track singlespeed frames allow the installation of a rear rim brake. But the wheel axle can be moved in the dropouts. Then the rim also moves. However, the brake should always reach the rim without readjustment. This means that the dropout slot must be made perpendicular to the top stay.

horizontal dropouts open to the rear. Sometimes there is a bolt in this unit to help align the wheel more accurately. Horizontal dropouts are a good solution, but they have a drawback: when installing the wheel and tensioning the chain, there is no guarantee that the wheel will be exactly the same as before. Often you will have to adjust the rear brake.

Sliding dropouts
The idea is clear in the picture

Eccentric carriage unit
There is a thread inside the frame to screw in a regular carriage. The eccentric assembly itself is inserted into the frame. The frame is sold already with it. The carriage cup of such a frame is much larger in diameter than usual, and there are no threads.

To tension the chain, the assembly is rotated in the frame and then secured with bolts. How exactly - there are possible options. The most common are bolts from below, perpendicular to the pipe wall. Typically these bolts are protected by short tubes welded to the bottom bracket shell.

Frames with eccentric dropouts
Although they are still considered strange even in decent countries, the emergence of several different brand standards indicates interest in such a solution. Moreover, in some versions it does not look as bulky as sliding dropouts.

This option allows you to avoid reinstalling the disc brake caliper when installing other chainrings on the singlespeed.

Trek has shown that the eccentric dropout works well with a detachable chainstay and chainstay joint (to accommodate a sling). Of course, a regular bushing for the chain also comes in here.

On bicycles with a gear shift system, the rear derailleur is attached to a holder on the rear right dropout, or to a special overhead bracket - a cock.

Holder
part of the dropout with a special fastening. The holder can be built-in or can be replaceable. In this case, it can be called a “rooster”.

Dropout with built-in holder, regular holder and dropout with built-in holder ("cock")

Chain tensioners They are usually used on vertical dropouts. A part similar to the rear derailleur is used to adjust chain tension. Some tensioners have one pulley, some have two. Tensioners are mounted mainly at the site of the rear derailleur. But there are also devices that are attached to the feather, to the seat tube, or even just anywhere.

Halflink chain (or 1 halflink in a standard chain) A chain with not ordinary links, but “half-links”

There is another option like phantom star, but, from my point of view, for its appearance it is on the verge of fantasy. The main thing and the worst thing is that under load the upper branch of the chain straightens, shifts the phantom sprocket down - and the branches of the chain simply stretch like shoelaces. If you break it down into strengths, you can see that icy wires stretch and break in about the same way.
Everything is so bad that when you press the pedals, you feel not the emphasis on the pawls on the rear hub, but the springy reaction of the chain. You stop pressing - the elasticity of the chain returns the phantom star to where it is in the photo

When riding, the load on a chain with a phantom sprocket is much greater than in any imaginable case.

However, that's not all. As practice shows, a singlespeed can be made on the basis of a regular hardtail, and without investing practically any money in it! For this you need a front sprocket, a rear sprocket and a chain (which is generally obvious). Moreover, they may not only be not new, but even very worn out, one might even say killed. On a conventional system with gears, they can no longer be used, since in the best case, the gears will shift poorly, and the chain will completely kill the sprockets, and in the worst case, it will simply slip over the sprockets. But on a singlespeed without a tensioner or on a frame base with horizontal dropouts, it simply has nowhere to go. And it works! It crunches and jingles, but it works, completely free. You may well have damaged parts lying around if they weren’t thrown away at one time, and it’s not difficult to find them for symbolic money. Thus, you don’t have to worry about drive wear, which, by the way, is especially important in winter with its eternal salt.
When assembling a bicycle, you need to select the sprockets as carefully as possible so that the chain is properly tensioned. It might be worth using a 22 tooth front sprocket, it will also reduce weight. You can also install a regular rear sprocket, but the hub drum must be strong enough, and it must be made of steel. If this is not the case, then you can assemble 3-4 stars from a standard cassette with steel pins holding them together. That is, to put it simply, take not one star from a cassette, but several. At the same time, it is worth making sure that the chainline is normal, since this is absolutely not difficult to do. It is enough to determine by eye the position of the driven sprocket at which the chain bends minimally. If the leading sprocket is 32, then the driven one should be in the place of the third or fourth sprocket of the cassette, counting from the smallest one. To prevent the driven sprocket from moving around the drum from side to side, use standard spacers between the sprockets from any cassette.

The chain runs with only a slight misalignment.

Of course, such a system has significant drawbacks.
- The chain wears out during operation and stretches. For killed sprockets and chains, this is not important, except that it starts to crunch a little. But the problem is that, as it stretches, the chain sags, and, therefore, with a certain wear, it begins to easily fly off the sprockets. This means that you lose the important advantages of singlespeed. You can place larger diameter stars next to the working stars, but this, of course, will not solve the problem. The solution is to look for the chain again.
- Since the chain must be very tensioned during installation (much more than on a system with gears), you may have to use sprockets that are not what you would like. For example, you want to put 32 teeth in front and 16 in the back, but the chain cannot be tensioned - it either sags or is so short that it cannot be connected. But I repeat once again, this problem can be solved if you have skillful hands, horizontal dropouts (well, or all kinds of eccentric carriages) and chain tensioners