Do-it-yourself bicycle tire repair

From ancient times, it was believed that someone who follows the advice of an old Russian proverb “prepare a sleigh in the summer and a cart in the winter”, without any doubt, can be considered a good, zealous owner. Being fond of cycling tourism for almost ten years, I was always engaged in repairing my "iron horse" and completing it with spare parts in the winter.

However, over the past couple of years, it has become almost impossible to do this either in winter or in summer, since it is possible to purchase the required parts in the store only as a result of a lucky break. The problem of tires is especially acute for cyclists. The last of the tires at my disposal was worn out in several places to a fabric cord, and its further operation became very doubtful.

Remembering that many motorists use welded tires, I decided to try to do such a “restoration” Looking ahead, I will say that the result exceeded all expectations: the restored tire, placed on the rear wheel, “skated” 1.5 thousand kilometers with minimal wear on the pattern tread, no delamination of the welded rubber layer was observed.

I think that the resource of such tires is at least three seasons of active driving. I suggest that other cyclists take advantage of my experience, especially since there are no special tricks in it. The proposed method of repairing a bicycle tire consists in restoring a worn tread not only in places of defects, but also over the entire surface in contact with the road surface.

To work, you will need an electric vulcanizer (preferably with a large area of ​​\u200b\u200bthe heating element, for example, a stationary type, having a working surface measuring 150X200 mm, as a way out, we can recommend “installation” from an iron with a thermostat and a clamp or a locksmith vice) You will also need raw rubber and not complicated equipment made by yourself. The latter consists of a matrix that forms the protector and a rear copy spacer. The matrix, as a heat-conducting part, is made of metal.

It can be both steel and cast iron. But it is best to give preference to aluminum alloys, since, along with good thermal conductivity, they have an important feature that allows an amateur who does not have machine tools at hand to use the most common metalwork tools for processing. So, in accordance with the radix of the wheel of your bicycle (for my "Sputnik" of the Kharkov Bicycle Plant it is 340 mm), the profile surface of the matrix is ​​​​made.

The type and shape of the "new" tread is determined by the diameter, depth and number of notch holes and recesses on the body of the matrix. The rear copy pad is easy to make from a wooden block. The specific dimensions of the entire tooling depend on the dimensions of the vulcanizer and can be changed accordingly, “adjusting” to the existing model. Preparatory operations include “guiding” roughness and obtaining a matte, “velvet” surface on the tire.

For this, a file with a large notch is used (it is desirable that it has not been used before for working on metal). After sanding, the surface is degreased with a rag soaked in gasoline. Cut off a piece of raw rubber with a thickness of 1.5. 3 mm, remove protective fabric or film stickers, moisten with gasoline and apply to the prepared area of ​​the tire.

Having installed the matrix on top, and the copy pad below, we clamp the package into the vulcanizer, preheated to a temperature of 140 .. 150 ° C. In this case, the displacement of parts relative to each other cannot be allowed.Do not forget during work and about safety precautions, try to protect your hands from burns. The duration of the vulcanization process is determined by the thickness of the rubber used: for the indicated one, it lies within 15.25 minutes.

As a result of proper heat treatment, the welded layer should become elastic, in no case should it stretch “like chewing gum”, or vice versa, be brittle and brittle. C), leading to burnout. Having moved the matrix and the gasket, we make the next bookmark, the vulcanization process is repeated, and so on until the updated tread closes

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Tire restoration: 1 - vulcanizer heating element, 2 - matrix, 3 - raw rubber layer, 4 - welded layer, 5 - back gasket, 6 - tire area requiring repair.

Everyone knows and knows how to seal a tube on a bicycle, but few people seal a torn tire. Today will give the bicycle rubber a second life.

In general, the first time I cut a tire on my road bike and was already thinking of throwing it away, but there was no money for a new one, so I decided to save it at all costs.

Also, this method is suitable if you just pierced the wheel with a large nail, twig, glass - in general, any object that could leave a hole in the tire through which sand and small pebbles can get inside. This small thing can rub between the tube and the tire, which will eventually lead to an unexpected puncture of your wheel.

To restore a tire, we need:

• Piece of an old camera
• Plastic bottle
• Glue
• Scotch
• Lighter
• Scissors

Let's break down our actions with tire repair by points:

1. Let's start with a plastic bottle. Cut out a rectangle with rounded edges from the bottle. For example, if you have a cut of 1-2 cm, then you need to cut a rectangle 2 times larger than 2-4 cm.

Next we need a lighter. We need it to melt the edges of the plastic patch. This is done so that the plastic does not cut through the tire and does not get worse.

2. Old camera. It is necessary to cut a rectangle from the camera, which will be 1-2 cm larger on all sides of our plastic patch, which was cut out a little earlier.

3. We glue the camera and plastic. We take super glue, if it is not available, you can use the one that comes in the first-aid kit for sealing cameras, but it will take longer to wait for the glue to grab. It turns out a kind of blank, which we will glue in the tire.

It is necessary to glue to the outer side of the chamber, since the inner side will not be glued due to the white coating.

4. We glue the "blank" to the inside of the tire, where the cut is located. We spread the "blank" around the edges and in the center and glue it to the tire.

Then we take adhesive tape, it is advisable to use adhesive tape with reinforcement and glue it on top. If there is no adhesive tape, you can also stick it with electrical tape.

That's all! You sealed a tire with a cut. Now you can ride your bike further and when the money appears to buy new tires. I have such a tire lasted a long time, until the tread is worn out. Therefore, the method works 100%

In the event of a puncture or other damage, it is rare that professionals help to seal the bicycle inner tube, and riders have to do everything themselves.

As with any incident, there is a “regular procedure” for repairing a camera at home. It implies that you have all the necessary tools, and behind you - at least a couple of cases when you had to remove and disassemble the wheels.

It will be difficult for beginners for the first time, but no fundamental problems should arise during the repair process.

So what are we working on. Mandatory set:

• keys and hexagons (for wheels without an eccentric);
• disassembly, also known as mounting, is a small tool for bending the tire from the rim, easily replaced with a screwdriver or even wrenches, allows you to work a little faster;
• basin, jar or other vessel with water - for diagnosing the site of damage;
• vise - for pressing the surface of the camera and the patch to each other.

As you can see, the mandatory set is very limited, which allows you to make repairs in almost any conditions.

Repair is carried out according to the standard procedure, after which at least once the gluing will not raise any questions.

The first thing to do is to remove the wheel with the damaged chamber. To do this, you will have to do the following:

1. We disconnect the brakes, if they are rim, wings, if they can interfere with the work with the wheel.
2. We flip the bike.
3. We unscrew the retaining bolts on the sleeve or eccentrics.
4. Carefully remove the wheel. In case of problems with the rear wheel, it will be most effective, while holding the chain, to first drive the wheel axle towards the saddle, and then, lifting it, pull it out.

Now nothing interferes with working with the wheel, you can proceed to the next steps.

Usually the most difficult step is to "get" the camera out of the assembled wheel. If you have the skill and the proper tool, it is very simple.

The wheel is disassembled with the help of mounts or any flat objects - screwdrivers, keys, even coins:

1. We completely lower the camera on the bike. To do this, unscrew the spool from the nipple. On good tires, this can be done using a groove in the cap, on cheap models you will have to hold the spool with your hands until all the air is out. In some cases, this step will have to be done before removing the wheel, as the wide cross-country tires will cling to the brakes and frame.
2. We choose a place on the back of the bicycle wheel from the nipple to start disassembly.
3. We drive the disassembly between the rim and the tire vertically down, trying not to touch the camera inside.
4. We retreat 10-15 centimeters from the first, we drive the second.
5. Carefully, as with levers, lift the tire until a small segment is behind the outer part of the rim.
6. Next, remove the rest of the tire with your hands.
7. We carefully remove the valve from the groove in the rim, take out the chamber.

The result of all actions is a disassembled wheel, in which the tire is “put on” over the edge of the rim, and a free chamber, ready for repair.

Finding damage is a creative thing, although quite primitive. Almost everyone recommends using a bowl or other vessel of water to help locate the point of damage from the bubbles, but this is not the easiest way, because you have to dry the chamber and risk water entering through the nipple in order to save a few seconds.

A much simpler and more accessible definition by ear:

1. We pump up a bicycle camera.
2. We bring it to the ear and look for the point where you can hear the etching of the air.
3. We localize the puncture site of the chamber along the air flow or visually.

Everything is very simple. It is only necessary to check that there is no damage around the valve. With such damage, it will no longer be possible to seal the breakdown without special tools.

Further, the repair kit comes into its own:

1. We clean the surface of fat with acetone or gasoline, in the field - with a clean cloth.
2. We pass around the surface with sandpaper (not a necessary step, but useful for the quality of gluing).
3. Remove the protective film from the patch.
4. We apply glue, according to the instructions on the tube, on one or two surfaces at the same time.
5. We strongly press the patch to the camera and hold it, trying not to move the parts relative to each other.

Then it remains to wait for the "seizure", which occurs, depending on the description, either immediately or within 5-15 minutes. In modern repair kits, the glue is usually quite fast, but at home you can also use the classic Moment, which will take several hours to harden. How to glue correctly is described in detail on the packaging of the tubes inside the repair kits.

In addition to using non-specialized adhesives, the patch itself can be made from an old camera.The main thing is that the rubber is intact and well cleaned.

After checking the tube (it should be fully inflated outside the wheel to make sure that any damage has been repaired), you can assemble the wheel and install it in place.

1. We check the insulating tape inside the rim (usually it is not fixed or it is easy to move during manipulation).
2. Carefully place the bicycle inner tube inside the rim, starting with the valve and making sure that there are no creases.
3. With the help of montages, similarly to removal, we “refuel” the tire into place. Before this, it is recommended to pump up the chamber a little so that it does not press against the rim.

The wheel is assembled, we fully inflate it for verification and proceed to installation. For the front wheel, you should pay attention to the marking on the tire in the form of an arrow, which is sometimes supplemented by the word Drive. This is the direction in which the wheel should rotate. We install the corresponding side so that the protector works correctly.

There are situations when there is no repair kit with you. It is impossible to predict everything, but we will give a couple of recommendations:

• The patch can be made from any rubber, including old tube, automotive or technical rubber.
• What kind of glue to use is not very important, as long as it is intended for rubber. It is better not to use hardening industrial and household compositions.

There is also an extreme case when, in a problematic situation, the rider is left without glue and tools, for example, a puncture was obtained while riding around the city, but you still need to get home. In such situations, there are also solutions. For example, the chamber is cleaned and a patch is applied to it in such a way that, when inflated strongly, the pressure presses the patch.

In other cases, if there is no patch, electrical tape or a moistened plastic bag is used. During situational repair by “applying”, the surfaces are not cleaned with emery, but, on the contrary, they are wiped as smoothly as possible so that there are fewer cracks.

Of course, all these methods are temporary, and they work only for a short time, subject to strict restrictions:

• The contact surface must be clean and smooth.
• Impact load on the wheel is prohibited.
• The pressure must be constantly monitored and be maximum.

A glueless method that came from the automotive world is vulcanization, which is also used on a bicycle. Requires special equipment, but reliably repairs punctures. The essence of the vulcanization process is that the stripped patch and the chamber are pressed against each other with great force and heating, in fact, they fuse, forming a single structure.

Vulcanization is much more reliable than any adhesive patches, but requires skill and additional equipment. By the way, there are "household" or home-made vulcanizers, consisting of a vise with a cylinder and a combustion chamber, for example, gasoline or other fuel. The only advice I can give is to be careful with fire.

It is easy to work with a repair kit, but there are several technological methods that allow you to repair cameras without it.

Perhaps the most interesting products in this area are self-sealing cameras. Their secret is that a special gel or resin is poured into the dense chamber. In the event of a breakdown, this substance flows into the gap and seals it. Thus, self-adhesive models allow you not to think about repairs for some time, however, such cameras cost at least twice as much as their conventional counterparts and weigh 1.5-2 times more.

Otherwise, preventing a puncture is very simple:

• Inflate the wheel properly. An under-inflated or over-inflated tire is prone to rupture from "biting" or pressure, respectively.
• Choose clean roads. The most common cause of punctures is iron screws, nails and glass. They are easy to avoid by simply observing the surface you are moving on.
• Do not storm obstacles head-on.The impact of even a shock-absorbed front wheel on a sharp side is guaranteed to cause damage, even if the breakdown did not occur the first time.
• Use "puncture tape", which is an extra layer of synthetic rubber that is placed between the tire and the chamber inside the wheel.

Camera repair at home is quite real. For its implementation, a minimum of tools and knowledge is required. It is enough to responsibly approach the issue and study all the steps. Of course, it is much more useful to monitor the wheels and the road before the accident, but in the event of a breakdown or damage there will be no problems and going to a workshop or tire shop to seal the hole is almost never needed.

Recently I cut my slick tire with something very sharp (continental citycontact, not folding). A cut on the sidewall, through, the camera was also cut.
Now it is definitely impossible to pump up the chamber in this tire to a standard pressure of 5-7 atm - a hernia will come out of the hole.

How to revive an item?

Advice aRoma » 25.6.08 15:42

Roma, I'll clarify: is this method also suitable for high-pressure tires?

Advice Tibor » 25.6.08 18:56

sergio,
And you will not be dumb to ride on such rubber? It may roll along the flat, but you will drive into a trap and it will burst nafik. Especially if you pump atmospheres up to 5. It's not even travel contact with reinforced sidewalls.
In my opinion, 100 grams for a new tire is an adequate price for calm nerves. in my humble opinion

Of course I don't care. Aby shoto write

Advice Tibor » 26.6.08 07:09

If you can simulate with a stitch 50TPI (tires per inch, i.e. 2 threads per millimeter), or how much a tire has, by tying them to the cut threads (cord), it is normal to vulcanize the cut (and not use the surface tension of a thin adhesive film), then you probably will not create a potential damage site on the tire. When stitching a cut, you are actually stitching rubber. Cord tends to stretch out of the rubber like insulation from wires. Yeah, the tires don't hold up very well.

Sorry for the wild imagination. It's me who's clean

think twice

Advice M i k » 26.6.08 09:35

How to revive an item?

Advice M i k » 26.6.08 16:26

This word in this context scares me :)

It's no secret that motorists do not know pressures above 2-2.5 atm, and the usual pressure of bike slicks is nonsense for them :)

Of course, the pressure there is less, but the tested loads depend not only on pressure. But in any case, with this tz. self-made gluing is unlikely to be reliable.
There is also a moment that sometimes the coated compound has such a composition that it does not stick much to it and sticks in the usual way.

ps I personally consider it justified to restore and use a dead tire only as a forced and temporary measure.
ps2 here's another thread
Sealing cameras and tires

Advice aRoma » 27.6.08 14:06

100 kg, I did not risk putting it on the back.
Serega, since the topic has already been raised, let's repair the tire in some way, try to put it on the front wheel and pump a little less than the norm, and then tell us how it behaves (just test it somewhere not far from Kiev).

Advice Tibor » 27.6.08 14:18

I was looking at Rema TipTop reinforced car tire patches. They have several significant drawbacks:
1) Dear;
2) Very large, thick, coarse and inflexible;
3) Requires native special glue (blue).

However, not everything is so bad. As it turns out, Park Tool makes self-adhesive patches for TB-2 bike tires.

Emergency protective patch for the tire.

The fastest, most convenient and safest way to patch a cut or bead wall wear. The TB-2 is constructed from a durable, waterproof vinyl membrane with woven fiber reinforcement. The heavy-duty pressure-sensitive adhesive ensures that the patch stays in place in any tube tire, road or mountain, high or low pressure. A true travel keeper.
TB-2 measures approximately 76mm x 45mm (3″ x 1.75″).The kit includes three patches. The thickness of one patch is about 0.5 mm.

Accompanying text on the package:
Designed to get you back on the road or trail, the TB-2 Protective Patch is quick and easy to install to patch cuts, scrapes and holes in any tire size.
A thin, reinforced film of a protective patch is glued to the inside of the tire and prevents the tube from crawling out through a cut or hole. Locate the cut or hole, then clean and dry the adjacent surface to help the patch adhere. Peel off the protective film on the back of TB-2 and apply, allowing TB-2 to adequately cover the damaged area.
Note: The TB-2 is designed for emergency use. A patched tire should be replaced as soon as possible.

Modern bicycle models have become a conglomeration of new materials and technologies. First of all, innovations concern the frame and the drive mechanism.

Only spoked wheels with a rubber tire and a metal rim remained unchanged. Eights, torn-out spokes and worn-out wheel hubs are already meeting the 21st century ... Therefore, the skill of straightening and repairing bicycle wheels is useful to every man.

There are many easy ways to save a wheel. Any repair of bicycle wheels begins with turning the bike over and placing it on the ground with an emphasis on the handlebars and seat.

The easiest way correct the received eight is to bend the rim over the knee. I used this simple Russian technique many times. Turning the bike over and spinning the wheel, I find the most convex place on the rim. I rest against this place with my knee, and with my hands I grab the tire with the rim to the left and right of the stop and straighten the rim with effort. Again I spin the wheel several times and correct it. Usually such manipulations are enough to reduce the curvature of the rim, and the wheel is already included in the fork of the frame.

The second step is to tighten the spokes, taking into account the remaining curvature of the rim. It is necessary to scroll the wheel and note the most curved places of the rim to the side. Then, in these places, the tension of the outer 2-4 knitting needles should be loosened, and on the inner row, the knitting needles should be tightened by 1-2 turns of the nut. By gradually loosening and tightening the appropriate spokes, you can make the rim fairly straight without disassembling the bike. To facilitate the work, the threaded part of the spokes is moistened with plain water.

After several such repairs in some areas, radial displacement of the rim and the appearance of its ovality are possible. Before the next spring-summer season, a more thorough straightening of the wheel should be carried out by removing the tire from the rim. The wheel freed from the tire is mounted on the frame of an inverted bicycle, and when it is slowly scrolled, the curvature and ovality of the rim are determined. To eliminate ovality, loosen the spokes in the region of a smaller radius and tighten in a convex place. This operation is repeated several times. pairwise changing the tension of all the spokes in the left and right rows.

As a result of such work, a completely even wheel with well-stretched spokes can be obtained. It is the spokes that hold the rim and transfer shock loads from the road through the hub to the frame.

The most difficult and time-consuming part of repairing wheels is their complete disassembly and subsequent assembly. Don't do this on your knee. For accuracy, an assembly fixture is required (Fig. 1). The simplest conductor is made on a sheet of thick plywood or chipboard, in the center of which a hole is drilled along the diameter of the wheel axle (photo 1). Then the radius of the rim is marked, and the stop bars are attached along the line of the resulting circle. Their height from the surface of the conductor to the rim is selected according to the dimensions of the rim and bushing (photo 2). Bonks should be placed symmetrically to the axis and evenly around the circumference.

Rice. 1. Assembly jig for wheels

Among the possible damage to a bicycle tire, there are those in which the replacement of the inner tube does not help. In a note, I will share this experience in repairing the sidewall of a Michelin Pro4 Service Course V2 bicycle tire.

A couple of years ago I chose tires for a road bike, more details here: Tires for a road bike, I want to go fast and not break through. I chose Michelin Pro4 Service Course V2 tires (for two bicycles on the farm). As for resistance to a puncture, there was confidence that there would be no regular problems on those roads on which we ride.

Indeed, for a season and a half, not a single puncture. Even such an insidious option as a metal cord from truck tires (resembling a small needle) was not caught. More precisely, I got caught once, but after a side cut.

But there were no illusions about the side wall. In half the cases, tires of this level of rolling fail not due to wear, but due to a side cut. This is due to the fact that the side wall is soft, thin, elastic. Otherwise, it will not roll, too much energy will be taken to compress and straighten the tire near the “contact patch”.

On the side, tires are usually cut with pebbles, which are often washed onto the road from the side of the road after rain. Or they are just scattered there in some places. The interaction of a pebble with a tire is worthy of a separate study. If in such a place along the road there is a metal chipper, then the pebbles sometimes hit it quite loudly, as if they were fired from a slingshot point-blank. That is, the pebble, as it were, is captured by the sidewall of the tire when the wheel hits, and then, when released, it is fired with very decent energy. Probably, if something goes wrong and the energy of the pebble turns out to be directed to the sidewall of the tire, and the pebble itself turns out to be with a sharp edge, then the tire may not withstand it. And it will not be a puncture, but a "bullet wound"

If possible, I try not to run into the pebbles on purpose, but since I am the “second number”, this is not always possible.

In general, one fine day at the 18th kilometer of the planned 70, a shot rang out from under the rear wheel, as if it had hit a primer. There is a hole in the sidewall of the tire with a caliber of 7.62 mm, and in the chamber, of course, which exploded.

I note that the tire was inflated almost to the allowed maximum.

Maximum pressure - 116 psi

With a maximum of 116 psi (marked on the sidewall), the tire pressure calculator gives my current "curb weight" the required pressure of 115 psi, which was "driven in". The tire itself passed one season on the front wheel (that is, in a gentle mode), we can say that it did not even squash. This is her second season in which she is working on pushing a curb weight from behind.

What to do if you catch a side cut? On the Internet, this is chewed in more than detail, so I was well prepared for this. Just in case, I will list three options in descending order of the reliability of monitoring the situation.

1. Carry a spare tire with you. Of course, this is necessary in responsible races, so in my case there was no tire.
2. Keep a set of Park Tool TB-2 patches (or similar) in the repair kit. This is a strong Velcro with an adhesive coating, glued from the inside. Unfortunately, I had a sad experience of storing ordinary self-adhesive patches for cameras in a repair kit, and a repair kit with glue. The fact is that punctures are rare for me. And when they happen, it turns out that the glue in the tube has dried up, and the adhesive layer on the patches has dried up long ago. Probably because of the summer heat. Judging by the forums, Park Tool patches really help, but instead I carry a “simplified” version, reinforced tape, with me.
3. Reinforced tape. So silver. It can also be different, I use the one on the packaging of which all sorts of options are drawn for “rolling” the car. By the way, my car is really covered with such adhesive tape in many places.

I stuck three layers of adhesive tape to the tire from the inside. When stuffing the necessary “nuts”, a small hernia appeared in place of the hole, but the camera was not at risk.

One could say that I had a great ride to the planned 70 km, but no, as I already mentioned, I also caught a wire-needle.I drive two cameras (because we ride together), so the cameras were enough for this trip "just right"

Repair of the sidewall of a bicycle tire is described quite well on the Internet, so I am unlikely to be original. However, there are a number of points that you need to pay attention to. The general principle is that during the repair, a sufficiently strong patch is glued inside, which should not allow the camera to squeeze out the hernia. But at the same time, of course, you need to say goodbye to the softness of the sidewall in this place. That is, the wheel will roll clearly worse. Yes, and the patch from the inside can fall off, because all the time it will bend, then unbend. Therefore, generally speaking, such a repair is not recommended. You could probably say the same about the bike. And on a car, in my experience, such repairs are simply prohibited, the tire is thrown out.

I chose a patch from durable rubber, which was found on the farm. I think that ordinary patches for punctures in cells are categorically not suitable, because they are easily stretched. Ideally, the rubber for such a patch should be reinforced with fabric, but I didn’t have one. The one that was found, to the touch is much denser than the patches for the cameras, it looks like the rubber of the sidewall of a tire. For some reason it was attached to a ski helmet

Before gluing the patch, the hole must be sewn up. Not so that the threads hold the gap, but so that the entire problem area sticks evenly to the patch, which will hold the load. The threads can then fray during operation, this is no longer important.

I glued it as usual (sanded it, degreased it, the first layer of glue was dry, the second one was working, I pressed it for a day). It turned out that the glue did not stick to the Michelin compound, everything remained on the patch. Maybe the glue was bad, universal based on gasoline, judging by the smell. I repeated the procedure with cyacrine glue (superglue).

It stuck great. The edges of the patch were “nullified” with a dremel with a “skin circle” type nozzle. Just in case, I also smeared the threads on the outside with cyacrine glue.

So far so good, but just in case I carry a spare tire with me.

spare tire

Didn't notice any deterioration, although in addition to the deterioration of the rolling parameters due to the internal blotch, I have so far installed an ordinary butyl chamber instead of a latex one. To be honest, so I suspectedbut now there is more to think about

Tire failures can be caused by mechanical damage and manufacturing defects. Mechanical damage includes punctures and cuts caused by foreign bodies that have entered the tire. The following damages are the result of manufacturing defects: stratification of the thread, rupture of the thread, rupture of the seam at the single-tube, delamination of the tread.

Significant damage penetrating the outer surface of the tire is easily detected by inspection. Other damage is determined by inspecting the tire after it has been removed from the wheel rim. To speed up the location of small punctures, in which the air from the chamber is released gradually, the tire mounted on the wheel is immersed in water. At the puncture site, traces of air coming out of the tire will be visible. It is necessary to immerse not the entire wheel in water, but only part of the tire so that the surface of the water barely covers the inner surface of the rim.

Having found the puncture site, it is marked on the tire with an indelible pencil, one edge of the tire is removed from the rim and the chamber is removed from under the tire. Having slightly pumped up the chamber, they find the puncture site by ear or by immersion in water and mark it with a pencil, and the chamber is freed from air. At the puncture site, the surface of the chamber is cleaned with a rasp, a file with a large notch or sandpaper with a large grain. On a separate piece of rubber 1-1.5 mm thick (cut from the old chamber), a surface equal to the section of the cleaned surface of the chamber is cleaned, and a patch is cut out of it with scissors, giving it a round or oval shape.From the camera and the patch, remove the dust and traces of emery remaining after stripping with a brush or a clean rag. A thin layer of rubber adhesive is applied to the surface of the chamber and the patch. The glue is allowed to dry for 15-20 minutes, and then a second layer is applied, which is also allowed to dry. After drying, the patch is applied to the damaged area of ​​the camera, pressed tightly and rolled with a roller or lightly pierced with a wooden hammer, placing the camera on the palm of your hand.

If the camera has large gaps, the sealing of which presents significant difficulties; the best way is to repair by inserting a piece of the old chamber with the same cross-sectional profile. To do this, a piece with a length of at least 120 mm is cut out from the repaired chamber, on which there is a gap. A piece 60–100 mm longer is also cut out of the old chamber (an allowance of 30–59 mm for each joint).

Gluing joints is most conveniently done using two mandrels, which are (Fig. 68 a) segments of a thin-walled steel pipe, the diameter of which is selected so that the chamber to be glued is put on the mandrel with little tension. The length of each mandrel is taken equal to 80-100 mm. The wall of the mandrel is cut through along the generatrix of the cylinder.

The end 1 of the rubber tube of the docking chamber is first passed inside the mandrel 2, and then it is turned inside out and pulled on the mandrel so that the latter is under the lapel. The same is done with the end 6 of the inserted piece of the chamber and the second mandrel 7. (Fig. 68 b). The end of the chamber, which will be internal after gluing, is turned out again with the outer surface up.

The length of the lapels should be equal to the allowance provided for gluing.

The outer surface 3 of the first end and the turned-out inner surface 4 of the second end of the chamber are thoroughly cleaned. An even layer of rubber adhesive is applied to the cleaned surfaces, and after drying, a second layer is applied, which is also allowed to dry for 15-30 minutes. After that, the ends of the chamber and the insert are joined end-to-end, and with the help of a thin wooden plate 5 placed under the lapel of the rubber tube, it is carefully turned back so that it lies on the surface of the second end smeared with glue over the entire area without folds or wrinkles. When the gluing process is completed, one end of the rubber tube will be inside the other. The place of gluing is pressed by hand.

After gluing the first joint, the mandrels are removed and the second joint is glued in the same way, connecting the chamber into a closed ring. After that, the mandrels are easily removed from the chamber due to the cut of the wall.

If the puncture hole is significant and several threads of the tire thread are damaged, the hole in the latter must be sealed. The patch in this case is made of rubberized fabric, which is available in the bike kit. On the damaged area on the inside of the tire, the surface is cleaned with sandpaper, several layers of rubber glue are applied at intervals of 15-20 minutes to dry. After that, a glue-lubricated and dried patch is also applied to the damage site and it is well rolled to the tire.

With significant cuts in the tire, it is best to repair it by hot vulcanization in the workshop that performs this work.

Repairing a damaged racing single tube is somewhat different from repairing a road tire and requires more care and attention. It is not recommended to submerge the racing single tube in water to find the puncture site. The puncture is determined by ear or, if this is not possible, soap foam is prepared, as for shaving (only not hot), and applied with a brush to the sides of the single-tube along the entire circumference; Foam will begin to bubble at the puncture site. The puncture site is noticed, and the foam is removed from the sides of the tire with a dry cloth.

The single tube is freed from air and removed from the rim.To remove the chamber from the tire, you need to carefully tear off the keeper tape glued to it from the tire frame, which closes the butt seam. The tape is torn off the tire in a fairly significant area. Being careful not to cut through the chambers, cut the threads of the butt weld; the incision is made so long that you can freely remove the camera. After that, the edge of the safety tape is undercut so that it is possible to freely remove the camera and repair it.

The damaged fabric of the tire carcass must be sealed during a puncture, since otherwise the thin wall of the chamber, drawn into the puncture hole in contact with the road surface along which the wheel moves, will be pinched or rubbed. The puncture hole in the tire frame is sealed with a piece of bicycle thread from an old single tube; you can also seal the hole with a dense canvas from a parachute or balloon.

The method of sealing a racing tire chamber is the same as the described method of sealing a road chamber, but due to the fact that the thickness of the walls of the chamber and the patch is only about 0.3 mm, and sometimes less, they must be cleaned with fine-grained sandpaper.

After the repair of the tire and the chamber, the latter is inserted into the tire and sewn up end-to-end with a cross seam. The crosslinking process is shown in Fig. 69. Then the seam is sealed with a keeper tape.

If it is necessary to strengthen the tread, a rubber strip 22–24 mm wide and equal to the circumference of the wheel, cut from a piece of rubber or from a road tire chamber, is glued to its surface. The strip, before sticking, is cleaned on one side, and then coated several times with rubber glue.

The protector is also cleaned and lubricated with glue. After the last applied layer of rubber adhesive has dried, the rubber strip is stuck on. When sticking, the strip cannot be pulled, otherwise the single-tube removed from the rim will sharply shorten in length and the tire frame will be covered with many folds, which adversely affects its safety.