Rubber is considered one of the most common materials today. Over time, the main characteristics can be significantly reduced. A fairly common question is how to soften the rubber. A similar procedure can be performed independently at home, it is important to follow all the recommendations.
Do-it-yourself rubber restoration
All materials lose their performance over time. Often you can find a situation where the rubber becomes too hard and loses its elasticity. If desired, you can restore the basic properties of the material, it is not necessary to throw it away. Rubber can be softened in a variety of ways. Among the features of this issue, we note the following points:
- Rubber cuffs and seals of some devices lose their basic properties over time. In this case, you can buy new consumables, since their cost is relatively low.
- Some elements are difficult to find on sale, due to their unusual shape and properties. In this case, softening can be carried out using various common technologies.
There is a fairly large number various ways softening rubber, the most common is to use kerosene.
What is needed to restore the elasticity of rubber?
Rubber is considered one of the most resilient materials. It is for this reason that it is used in the manufacture of various seals. After the seal ceases to be affected by the load, it is able to return to its dimensions. This moment determines the spread of the question of how to restore the elasticity of rubber. Over time, this property is also lost. If the surface is worn too much, cracks appear, due to which the insulating qualities are significantly reduced.
You can soften rubber at home using common substances. The most commonly used substances are:
- Kerosene can easily restore the elasticity index. This substance is ideal for processing small products; you can soften them by soaking them.
- Ammonia can be used to soften the structure. To do this, it is enough to create a small bath in which the product is lowered for several hours.
When soaking rubber in a recovery liquid, it should be borne in mind that the material can increase significantly in size. To remove the substance from the surface, the product is thoroughly washed with soap and water.
In some cases, hot water can be used to soften the rubber. This method is used to restore the insulation of the doorway of the refrigerator. You can enhance the effect achieved by wetting the surface with silicone.
Seals from the material in question are also used in the manufacture of windows. To improve the insulating qualities of the rubber bands, they are wiped with silicone and glycerin from time to time. Such substances can be purchased without any problems.
How to give elasticity to rubber?
- Rigidity increases if the rubber is kept dry for a long time. Elasticity is restored by wetting the surface with oil. Softening is recommended to be carried out periodically to achieve the desired result.
- Car wipers can be lubricated with silicone grease, due to which the surface is softened. Of course, it is possible to restore the old structure only if there are no mechanical defects.
In addition, on sale you can find special formulations, which can soften the structure after application.
How to soften rubber at home?
At home, you can soften rubber by using various materials. The most widespread are:
- Kerosene.
- Castor oil and silicone.
High temperatures also cause the rubber to become softer, but the wear resistance decreases.
Kerosene
When considering how to soften rubber, many give the possibility of using kerosene. Such a substance is able to restore the elasticity index.
Application features are that the product is soaked in a special bath, after which the surface is thoroughly washed and dried. If the length of the product is large, then it can be rolled up. Aged in kerosene to soften for several hours, as kerosene does not act immediately.
This substance is widely used, it can also make the product softer. The procedure is as follows:
- A container of a suitable volume is selected.
- Ammonia is diluted in water to obtain the required solution.
- The product is placed in the solution for an hour to soften.
- After that, the softened element is taken out and washed with clean water.
Drying is carried out at room temperature. It should be borne in mind that high and low temperatures always negatively affect the condition of the rubber.
Silicone and castor oil
A short-term effect can be achieved if silicone and castor oil are used. Among the features of the application, we note the following points:
- Silicone has only a temporary effect. It can be purchased in specialized stores.
- After lubrication, you need to wait a while. Silicone can be absorbed into the structure, making it more elastic.
After half an hour, the rubber will be ready for use. It should be borne in mind that the achieved effect will be temporary. When considering how to soften such material, you can pay attention to castor oil.
Heating
In some cases, only a temporary softening is required, for example, when putting a hose on a nozzle. In this case, you can solve the problem by temporarily lowering the product into a hot bath. After some time of exposure high temperature elasticity increases.
With prolonged use, the rubber can become dull. Problems can only be solved if the product is boiled. Significantly increase the effectiveness of the procedure by adding salt to the composition. Boiling is carried out until the moment when the surface becomes elastic.
If there are difficulties in removing the tubes and hoses, then the heating is carried out by exposure to a warm air stream. For this, a building or ordinary hair dryer can be used. When the high temperature air flow is concentrated in one place, plasticity increases significantly.
In conclusion, we note that only in the absence of defects can the restoration of the material be carried out. Some of the recommended methods may lead to the deterioration of some performance characteristics. That is why you need to follow all the recommendations.
The tires of a car are the only element of the vehicle that connects it to the road. Often car owners forget that rubber is the most important element of a car that directly affects. But when the tires wear out, every driver regretfully understands that it's time to spend money on buying new tires. . After all, sometimes tire wear can indicate possible faults car. In this case, replacing the rubber with a new one may not help. For example, with some types of breakdowns, your new tires may wear out prematurely in a short time. Let's take a look at ten of the most by which it is quite possible to determine the cause of this wear and tear, eventually finding out the technical condition of the vehicle.
1. Wear of the rubber tread in the center (in the middle)
What it looks like: With this type, as a rule, the tread in the middle of the tire is worn the most (example in the photo).
Cause: If the tire wears the most in the center of the wheel, then this indicates that the central part of the tread had the most contact with the road surface, compared to the tread closer to the edges of the rubber. Therefore, the car on which this rubber was installed did not have sufficient grip with the road surface. Accordingly, the traction of the machine was insufficient.
Most often, such wear indicates that the tire was not properly inflated. That is, the tire pressure did not correspond to the pressure recommended by the car manufacturer. This type of wear indicates that the owner of the car did not check the pressure even with sudden changes in temperature outside, at which the pressure in the tires can change significantly.
The fact is that while the tires are cold (for example, after a frosty night), the tire pressure may be lower than the manufacturer recommends. But after the start of the movement, the pressure in the tires begins to rise from the heating of the air in it. As a result, after a certain distance traveled, tire pressure may exceed the maximum allowable rate recommended by the automaker. As a result, the pumped-over unevenly adjoins to pavement resulting in uneven tire wear in the center of the tread.
Some motorists often advise to improve handling and reduce fuel consumption, on the contrary, to pump over the wheels. But this is not justified. Yes, in this way you can reduce fuel consumption a little and even improve handling a little, but in the end you will pay for it with faster tread wear.
That is, saving a little money on fuel, you will pay a lot more.
2. Tire bulging (bulging) and side wall cracks
What it looks like: Cracks and bulges on the side wall of the tires.
Cause: This usually comes from hitting a pothole (hole) in the road, a curb, etc. Usually the tire is well protected from such impacts. But if the tire is under-inflated or over-inflated, there is a great danger that the tire will be damaged as a result of the impact. Large cracks on the side wall of the tire that run along the rim of the wheel indicate that it has been used for a long time with insufficient pressure. Small cracks on the side surface of the rubber indicate external damage or the age of the rubber (due to age, the rubber compound begins to chemically break down, causing the tire to begin to crack).
A herniated tire looks like a bulge on the surface of the rubber. Most often, a protrusion (hernia) appears on the side wall of the tire. Herniated rubber is associated with internal damage (rubber layer). This usually happens due to a side part hitting a curb, pole, etc. Most often, after an impact, a hernia (protrusion) of the wheel does not immediately appear. That is, after a stroke, you can see a hernia only after a week or even after a month.
If you notice cracks or hernia on tires, then you need to buy new tires as soon as possible.
Remember that it is very dangerous to use rubber with a hernia..
3. Dents in rubber
What it looks like: According to long-term observations, rubber with dents looks like in the photo. That is, the tire has the form of tubercles and dents.
Cause: This type of tire is usually associated with (wear or damage to the elements of the chassis of the car). Due to a malfunction of the suspension, shock mitigation on bumps is insufficient. As a result, the tire experiences an overload from impacts, taking on the maximum load. But the load is distributed unevenly over the entire tread surface. As a result, some areas of the tread take on more load than others, which contributes to the formation of dents and bumps on the tires.
Most often, this appearance of used tires is associated with poor shock absorbers. Although it is worth noting that any parts of the suspension that have failed can cause this kind of wear.
We advise you in case of detection of such deformation of the tires, to make a complete suspension and racks of the car in the technical center. We do not recommend dealing with a similar problem at a tire fitting, i.e. in order to determine the cause of the change in the shape of the wheels. It is not uncommon when tire workers do not know what can cause irregularities (dents, bumps) on the tread surface.
Most often, tire workers claim and believe that this is the cause of improper camber. But this is not a fact. As we have already said, this reason may be due to the failure of the shock absorber (s).
4. Diagonal dent with signs of tread wear
What it looks like: Diagonal dent on the tread surface with uneven wear on the tire surface.
Cause: Most often this problem occurs on the rear wheels, where the camber is incorrectly set. Also, a similar deformation of the wheel can be associated with an insufficient rotation interval, and also, sometimes a similar change appearance tires may be associated with the frequent transportation of heavy loads in the trunk or in the car.
A heavy load can change the geometry of the suspension, resulting in diagonal deformation of the rubber tread surface.
5. Excessive tread wear at the edges
What it looks like: The inner and outer tread has increased wear, while the middle of the tread is significantly less worn.
Cause: This is a sure sign of insufficient. That is, the pressure does not correspond to the norm recommended by the car manufacturer. Remember that this is the most dangerous tire condition. The fact is that with reduced pressure in the tire, it is subject to greater bending. According to the laws of physics, this means that when the wheel rotates, the tire will accumulate more heat. As a result, the rubber will not evenly adhere to the road surface and, accordingly, we will get uneven rubber wear.
Also, insufficient pressure in the tires will lead to the fact that the rubber will not sufficiently soften the blows on the road, which will naturally directly affect the suspension. Over time, this hard impact on the suspension can lead to premature suspension failure, as well as affect the wheel alignment.
How to avoid the problem of under-inflated (insufficient) tires: We again return to the fact that every driver should regularly check the air pressure in the tires, that is, every month or every time after a sharp change in temperature outside. Also remember that cold tires (when parked at night) may show pressures lower than those recommended by the vehicle manufacturer. But during a long trip, due to the heating of the air, the pressure may exceed the norm.
The fact is that this system usually warns you of a change in tire pressure, either when there is a sharp pressure fluctuation (for example, a sharp drop in tire pressure by more than 25 percent), or when there is a significant decrease in pressure for a long time.
In other words, the tire pressure warning system can only be activated when the tire pressure is significantly lower than necessary. This means that you run the risk of driving for a long time on wheels with insufficient air pressure.
6. Convex side tread wear
What it looks like: The side blocks of the tread, usually similar to the plumage of birds, have. The lower edges of the tread blocks are rounded, while the higher edges of the blocks are sharp. Note that you cannot visually notice this kind of wear. This can be understood only when examining the tread from the edge and by touch, i.e. with hands.
Cause: With this type of tread wear, check the ball joints and wheel bearing first.
It is also necessary to check the stabilizer bushing, which, in case of failure, can lead to improper operation of the suspension stabilizer, which will eventually lead to this type of wear on the rubber tread.
7. Flat wear spots
What it looks like: One spot on the wheel has more wear than the other.
Cause: Single spots of increased wear on the surface of the tire are often found when forced hard braking or skidding, or when taxiing out of a situation in order to avoid an impact (for example, if an elk or other animal did not unexpectedly run onto the road). Especially such wear will be visible after heavy braking with simultaneous skidding, if the car is missing.
The fact is that when braking hard and taxiing in order to get away from the impact, a car without ABS is more prone to skidding with locked wheels, which will lead to something like this type of worn spot on the tire tread.
Also, similar stains can appear in cars that have been parked for a long time.
Remember that when you park your car for a long time, you risk tires where wear spots will appear on the tires of your car due to the uneven distribution of the weight of the car on them. The fact is that during parking, the rubber tread does not completely come into contact with the surface and, as a result, a certain section of rubber is deformed from a long parking.
8. Wear on the leading edge of the tread
What it looks like: The leading edge of the tread block is worn, and the rear of the tread has more sharp corners. Please note that this type of wear may not be visible during visual inspection. Therefore, check the protector with the edge by hand. If you notice that some tread corners are sharper (like hacksaw teeth) compared to other tread edges that are smoother, then this is real wear and not the norm, as many drivers usually assume.
Cause: This is the most common tire wear. Since this type of tire wear is very common and many car owners think that this is the norm, it is not. In fact, this wear indicates that the wheel has insufficient rotation. Therefore, it is necessary.
Most often, the reason is associated with the wear of the suspension elements (salint blocks), with the wear of the ball bearings, and also due to the wear of the wheel bearing.
9. Unilateral tire wear
What it looks like: One side of the tire is worn more than the other.
Cause: Usually, with this type of wear, the cause may be an incorrect alignment of the collapse of the car. This kind uneven wear The rubber tread is due to the fact that it is not exactly on the road surface due to incorrect wheel alignment.
In order to set the wheel exactly in relation to the road surface, it is necessary to adjust the wheel alignment.
Also, similar wear can occur with damaged springs, ball joints, suspension bushings. In particular, one-sided uneven wear of the tread may appear when transporting heavy loads by car.
In addition, some models of powerful sports cars have a special wheel alignment, which leads to a similar uneven tire wear. But this is rare.
10. Tire wear to indicator
What it looks like: Many tires have wear indicators between the tread. As a rule, these are special inserts that help you determine when it is necessary to change tires for new ones. Usually the height of these inserts is lower than the height of the tread. As soon as the tire tread is equal in height to the wear indicators, it is necessary to purchase.
Cause: Typically, tire replacement should occur after the tread depth is lower than recommended by the tire manufacturer. It's not always easy to tell by eye. Therefore, many tire manufacturers install wear indicators on tires (between the tread). As soon as the tread height wears down to the height that the indicators have, then it's time to change the wheels to new ones.
A rubber tread with a certain depth is necessary in order to divert water from the tire and prevent the car from hydroplaning on wet roads.
If your tires do not have a wear indicator, then you can measure the tread depth yourself in order to understand whether it is time to buy new tires. To do this, you need to use a coin, which must be inserted into the tread with an edge and measure the depth with it. You can read more about traditional tire wear here or check out our infographic.
Attention! For summer tires the minimum tread depth must be at least 1.6, 2 or 3 mm (depending on the rubber manufacturer).
For winter tires the minimum safe tread height should be at least 4-6 mm
Deformation is a change in the size or shape of a solid body under the influence of external forces. Applicable to tires, two types of deformations can be distinguished:
- functional deformation;
- Critical deformation.
Functional deformation is part of the scope of duties that a modern tire must perform. Namely, to deform, reducing the vibration and noise impact on the car and the driver, which occurs when the tire rolls on the road surface. The flexibility of the tire structure as well correct pressure inside, they allow the tire to perform this function without problems, while making a huge amount of deformation per unit of time without negative consequences.
Critical deformation It is precisely characterized by the fact that its consequence may be the complete or partial destruction of the tire, excluding its further use. Critical deformations include:
Warehouse;
Occurs when the car is parked for a long time;
As a result of driving with a pressure lower than recommended;
Shock with the destruction of the sidewall.
Tire deformation resulting from improper storage
The damage that a tire receives when the tire storage rules are violated is a fairly common operational damage that is not a consequence of the tire performing its functions. Among this type of critical deformation, the following tire damage occurs:
- bead ring fracture that occurs during long-term storage of herringbone tires. Unfortunately, storage in this way is a very common practice, although tire manufacturers recommend using it only for the limited time needed to transport tires. A bead ring fracture is a non-repairable defect, and it is not recommended to install such tires on rims.
How to avoid:
Carefully inspect new tires upon receipt: tire bead rings must have a strict round shape without minimal kink. In addition, during long-term storage, it is recommended to put the tires on the tread, in a vertical position, using special racks that do not damage the tires.
- tire curvature during storage in stacks . This method of storage is still common, and it is also especially dangerous for those tires that ended up at the bottom of the pile. And the higher this design, the more the lower tires suffer. Such storage can cause the tire to warp internally, which in turn can cause the tire to side-slip, as well as uncontrolled imbalance or vibration.
How to avoid:
Buy tires in and avoid those stores where there are a huge number of stacks of tires (more than four tires high) on the trading floor. Since the internal curvature of the tire cannot be seen by visual inspection, and only balancing machine will help identify the first signs of tire problems. Tire storage by the owner should also avoid stacking tires, even if the number of tires is limited to four.
Tire deformation that occurs when the car is parked for a long time
Few people know that tires can be damaged and from staying upright for a long time, with air inside. As a rule, this is possible when the car is parked in one place. This position deforms the tire, depriving it of a perfectly round shape. When driving on such a tire, vibrations and noise may occur. Non-repairable damage to the internal structure of the tire is also possible, especially for tires that have been in operation for a long time.
How to avoid:
The technical documents recommend limiting such extended stays to two days for fully loaded vehicles and up to ten days for unladen vehicles. Vehicle. If you need a longer parking of cars, you should reduce the load on the tires using stands or moving the car.
Tire deformation due to low pressure driving 
One of the most common forms of critical deformation is irreversible tire change, which occurs due to the operation of a tire with a low internal pressure. Due to this insufficiency, normal working deformations become redundant, and the tire walls, not designed for excessive bending, begin to heat up beyond measure. Thus, the destruction of the tire itself begins. First, the sealing layer is destroyed: it begins to bulge on the inner surface of the junction of the sidewall and the treadmill, then it peels off, and a rubber coating is formed. Then the sidewall, exposed to the carcass threads, begins to crack, and the air leaves the tire. Further driving on such a tire can lead to a complete separation of the sidewall from the tread.
How to avoid:
Monitor pressure. In addition to checking, you need to regularly change the valves, repair tires in a timely and high-quality manner, and prevent driving on damaged tires. Since all this can lead to a slow loss of pressure and to the appearance of a critical deformation of the tire.
Tire Deformation Under Shock Impact Load
At tire hitting a hole, hitting a foreign object on the road, tire deformation may occur, which can destroy the product at a time. If this happens at high speed, and the edges of the pit or object are sufficiently hard and sharp, then the chances of an instant destruction of the tire increase significantly. In such a situation, the sidewall of the tire is pinched between the rim and the surface, for example, in pits. The influence of other factors (speed, aggressiveness of the obstacle) leads to the appearance of an impact force that breaks several threads of the frame. The weakened part of the sidewall of the tire is easily deformed by internal pressure, and a hernia appears. Further operation of the tire is not recommended.. It is worth noting that sometimes the rupture of the carcass threads is accompanied by a rupture of the inner and outer layers of the sidewall of the tire, leading to a loss of pressure, which, of course, excludes further repair of the tire and its use.
How to avoid:
Cautiously, slowing down, drive through sections of the road with poor coverage, avoid hitting curbs and other foreign objects. If bad roads are a fairly common occurrence, then it will not be superfluous to pay attention to technologies that protect tires from damage. For example, Michelin uses IronFlex technology for some of its models (, X-Ice North 3, X-Ice 3), which reduces the likelihood of damage to the sidewall of the tire during shock deformation. For the same purpose, a double frame is used for off-road tires families , which also reduces the likelihood premature exit tires out of service due to damage to the threads of the carcass.
I know from my own experience that not all rubber products can be restored; to give them their former elasticity and softness, after it has hardened. In general, a small part of rubber can be brought back to life if we are talking specifically about rubber, and not about the latest polymers, which do not lose their physical properties at a certain operating temperature.
The whole difference is that rubber products, namely the "rubber" material itself, in the course of its manufacture, undergoes such a process as vulcanization, when the base of rubber - rubber turned into rubber when interacting with certain substances at a certain temperature. Rubber was a new material in which rubber molecules created a single spatial grid, it is due to this single grid that rubber has its physical properties.
It will not be practical to talk about all rubber products in one recommendation, since there are a lot of rubber types and each rubber has its own incoming properties, as well as the degree of saturation of the rubber, the ability to crystallize and orientate, the strength of the chemical bond chain and the flexibility of macromolecules.
Basically, 5 main factors influence aging and loss of elasticity:
- light exposure, in which the irreversible process of photooxidation of rubber occurs.
- ozone exposure, which results in cracking of stressed rubber.
- thermal action destroys the spatial grid.
- radiation exposure destroys the bond of molecules.
- vacuum action breaks separate sections in the product.
All this negative influence leads to the fact that the rubber becomes hard and / or brittle. If the product crumbles, then it will not work to give it elasticity, since the bond between the molecules is broken.
But if the rubber has hardened, but has not begun to break down, then it can be brought back to life.
One of the misconceptions is that many advise to dip or spray the product with solvents, gasoline or alcohol. This cannot be done, because, firstly, there is oil-benzo resistant rubber, which simply will not accept these liquids, and secondly, other rubber products simply dissolve partially or completely in these solvents, and the elasticity effect will be only temporary.
But one of the really effective solutions that can "revive" rubber products is ammonia solution with 5% concentration.
In this solution, the product should be held for no more than 15 minutes, then, if possible, knead it by mechanical pressure and treat it with the following composition.
Place the product after softening in water-glycerin solution with 5% concentration.
In this solution, the product must also be held for no more than 15 minutes.
The temperature of the solutions should be in the range of 40-50 degrees.
There should not be much time between the two solutions, since ammonia will destroy the rubber with prolonged exposure, and glycerin in water slows down this process.
Ammonia solution 5% is not on sale, for this reason you will have to buy 10% and dilute it with distilled water according to the formula (see chemical formulas, I personally can make a mistake)
A water-glycerin solution of 5% is also not on sale, there is only pure glycerin or 85%, it must also be diluted to obtain the appropriate concentration.
Tires are one of the most wear and tear parts of a car. But what if they wear unevenly. To begin with, this uneven tire wear should be correctly identified in order to determine its causes. How does tire wear unevenly?
- in various places of the circumference - at certain points of the tread it is heavily worn (spots),
- on the different side of the tire - the outer, inner side of the tire or its central area around the entire circumference,
- one tire wears out much faster than the others,
- a pair of front or rear tires wear out faster.
Let's now give the reasons and consider the nature of tire wear for each cause. We will consider these reasons from the most common to the least common.
The tire is worn in the center or on the sides. The reason is insufficient or excessive tire pressure.
Incorrectly exposed will certainly lead to the fact that their abrasion proceeds unevenly. Trying to identify this cause on specific worn wheels is a waste of time. The pressure can change in each wheel differently, even if you always pump up only all four wheels.
But this reason can be determined by the nature of the wear of the tread itself. The fact is that an under-inflated tire, as you know, sags, and therefore the sides of the working surface wear out faster. But for over-inflated tires, on the contrary, the central part is erased faster, since under excess pressure it is this pressure that pushes out the most, as a result of which, the most load falls on the axis of the circle.
The result of driving on overinflated (top) and underinflated (bottom) tires
Only certain areas of the tire are worn out. The reason is a deformed disc or wheel balance is disturbed
A deformed (crumpled, "figure eight", etc.) disc can also often cause uneven wear of rubber. In this case, wear will occur in certain places (spots) of the tread. If the disk "eights", then the wear will be in the form of two spots: one on one side of the tire in a certain place, and the second - in the diametrically opposite place of the tire and on the opposite side. When the disk is deformed, the tire wears out very quickly, depending on the degree of deformation, of course.
The tire is subject to similar wear in the case of wheel imbalance. Although, this happens much more slowly than with a deformed disk.
And in both cases, an additional symptom is a beating on the steering wheel or throughout the car. A visual inspection of a worn wheel will help identify this deformation.
Sometimes the rubber itself can become the cause of increased wear - its marriage in the form of a broken metal cord. The cord can burst if the rubber has already worn out significantly.
Only the inner or outer side of the front wheels wears out. Cause - wheel alignment
If the front wheel alignment is out of alignment, then your two front wheels are not parallel to each other. They either "clubfoot" - they look forward, a little to the center with the projection of the direction, or they are inclined to one side or another relative to the vertical axis.
As a result of this, you get excessive wear on the rubber of only the front wheels or with inside, or from the outside.
If a similar situation occurs with rear wheels, then there is a bent beam (if any) or one of the failed (possibly also bent) suspension elements.
The outer side of the tires can also wear out due to a faulty silent block or ball joints.
Only one wheel wears out. Cause - something happened in the suspension or wedge brakes
If a component in your suspension is worn or loose, such as a leaky strut, it can lead to excessive tire wear on that particular wheel. If any part of the suspension is not working properly, the wheel will bounce more or it will be harder to go over bumps in the road. This creates additional friction on that tire, causing a significant reduction in tire life and tread condition.
Here, as a rule, there is uniform wear of only tires on only one wheel.
Now imagine that you are driving around all day with a little pressure on the brake with your foot. This is what it sounds like if some brake component is stuck, such as a caliper (its piston). This usually happens only on one wheel, and because of this, it wears out faster (even wear occurs).
Only the front wheels wear out. Reason - something happened in the steering
Almost every part of the steering system can also lead to tire wear. But here we will only talk about the front wheels, and the nature of wear can be completely different: both in spots and on one side of the tire around the entire circumference of the tread.