When it comes to checking tire tread, there are a number of methods that can help you know if it’s time to replace a tire. Heavily worn tread will prevent a tire from performing as designed and can lead to unsafe driving conditions. One of the simplest, most common ways to check tread depth requires nothing more than a penny and a few moments of your time.
In the United States, tire tread depth is measured in 32nds of an inch. New tires typically come with 10/32” or 11/32” tread depths, and some truck, SUV and winter tires may have deeper tread depths than other models. The U.S. Department of Transportation recommends replacing tires when they reach 2/32”, and many states legally require tires to be replaced at this depth.
The idea of the penny test is to check whether you’ve hit the 2/32” threshold. Here’s how it works:
Place a penny between the tread ribs on your tire. A “rib” refers to the raised portion of tread that spans the circumference of your tire. Tire tread is composed of several ribs.
Turn the penny so that Lincoln’s head points down into the tread.
See if the top of his head disappears between the ribs. If it does, your tread is still above 2/32” , If you can see his entire head, it may be time to replace the tire because your tread is no longer deep enough.
When performing the penny tire test, remember not only to check each tire, but to check various places around each tire. Pay special attention to areas that look the most worn. Even if parts of your tread are deeper than 2/32”, you should still replace the tire when any areas fail the penny test.
Consistent wear around the whole tire is normal, but uneven tread wear could be a sign of improper inflation, wheel misalignment, or a variety of other things. If you see uneven tread wear, you should have a technician inspect your vehicle.
A simple way to check your tire tread depth is by using a tread depth gauge.
You can find tire tread depth gauges at your local auto parts store. There are many models available, but an inexpensive simple graduated probe gauge will work just fine. All you have to do is stick the probe into a groove in the tread and press the shoulders of the probe flat against the tread block and read the result. All gauges should measure in both 32nds of an inch and millimeters.
Another indicator of worn out tread already lives in your tires themselves. Every performance, light truck, or medium commercial tire comes equipped with indicator bars (or wear bars) embedded between the tread ribs at 2/32”. They’re there to help you monitor tread depth and make decisions about tire replacement. Just look to see if the tread is flush with the indicator bars. If they are, it’s time to replace the tire.
While the penny tire test does deliver on what it promises – indicating whether tread has reached the legal limit – it may not be the best indicator of whether your tires are safe for the road.
Tire performance can diminish significantly before your tread hits 2/32”. Even though the law deems fit for safe driving may not prevent you from hydroplaning or losing control in rainy, slushy conditions. If you think your tires may be close to needing replacement, have them checked out by a licensed mechanic.
Your tires form the essential bond between your vehicle and the ground. The tread grips the road as you drive. But if it's not deep enough, your car loses traction and suffers extended braking times. Shallow tread grooves make it harder to control the vehicle in wet weather and the chance of aquaplaning increases.
To ensure your safety, measure the tread depth as part of your regular vehicle maintenance.
Tread is the rubber on the tire that touches the road. New tires have an average tread depth of 8 to 9 millimeters (10/32 to 11/32 inches). As you drive, the tread will wear down. A tire with a tread depth below 1.6 millimeters (2/32 inches) lacks grip. Braking distance and vehicle control are impaired. These tires are not safe for driving and must be replaced.
Please consider that safe driving in wet and snowy weather conditions is affected by the tread depth, the pattern design and the rubber compound of the tread of your tires. On wet or snow-covered roads braking performance will progressively decline with lower tread depths. On wet roads there is an additional increased risk of aquaplaning with fading tread depths.
Therefore, check your tires regularly, reduce your speed on wet and snowy roads and consider replacing your tires in good time.
Ensure your vehicle is equipped with the correct winter, summer, or all-season tires.
Tread wear indicators, or wear bars, are spaced evenly through the main grooves in the tire tread. If they are flush with the level of the tread, then the tire should be replaced.
Several winter tire models are equipped with winter tire wear indicators. If they are flush with the level of the tread, the tire is no longer suitable for winter driving conditions. In some locations, they may also no longer legally qualify as winter tires.
The tire tread grips the road and wears down as you drive. To ensure your safety, measure the tread depth as part of your regular vehicle maintenance.
If you have a tire tread depth gauge, use it to measure the tread depth. Insert the probe bar into the groove and push the shoulders flush with the tread. Check the top of the gauge to see the measurement. Alternately, a small ruler can be used.
Be sure to check in various locations. A misaligned wheel may result in uneven treadwear.
Keep an eye open for any areas that look more worn than the surrounding surface. The tire's tread should be judged by the lowest depth you measured.
If you are uncertain of the measurements, take your vehicle to a service center.
While measuring the tread, look for cupping, or scalloping. These are small scoops, or divots, carved from the tread. They can indicate misalignment or other problems with your vehicle. Take your car to a service center.
Also, watch out for bulges in the tire tread or sidewall. They are not safe. You need to get a new tire.
Wheel fasteners loosen for many reasons, but the most common is incorrect tightening of the fastening nuts. Broken studs as a result of loose nuts are common. For the same reason, it often breaks holes on disks, deforms nuts and studs. “Twisting” is also not recommended: when twisting with more force than necessary, the disk and studs can be damaged, and when driving, the wheel will come off the vehicle.
If you tighten a nut to the recommended torque (which generally depends on the size of the nut), it will not loosen. But periodically, you should still check the reliability of the tightening and tighten the wheel nuts. nine0005
The forces that hold the wheel rim and hub together are generated by the frictional force in the thread of the nut on the stud and the frictional force of the nut against the rim. Before the wheel nuts are securely fastened, they will have to be tightened several times, especially on new wheels, in which the paint layer at the points of contact between the nuts and the disk, collapsing, further weakens the friction forces. On a new truck, the tightening of the nuts should be checked after the first 50 ... 70 and 100 ... 150 km of run, and then at each regular maintenance, the frequency of which depends on the operating conditions: this may be after 15 thousand km, or maybe after only 3 thousand. km. nine0005
The fastening of the trailer wheels should be tightened more often than the wheels of the tractor, because when moving, the trailer throws from side to side and lateral forces act on its wheels, which “loose”, weaken the wheel fastening.
Modern wheels are mounted with tapered (older design) or flanged nuts. The advantages of fastening with flange nuts are that the fastening holes do not have a chamfer and, therefore, such a defect as wear (“breaking”) of the chamfer is excluded. In addition, with the same torque, the pressing force of the flange nut is higher than that of the conical nut. When fastening with conical nuts, if the angle of the cone of the nut and the chamfer on the disc do not match (when using a non-original nut), the nut may be firmly stuck in the hole and it will not be possible to unscrew it. For flange nuts, it is recommended to apply grease between the hex part and the washer. In this case, it is necessary to ensure that the lubricant does not get on the surface of the washer pressed against the disk and does not weaken the friction force. nine0005
Over time, the force with which the mating surfaces are pressed is weakened, for example, if the thread is worn. Do not attempt to repair worn threads on the wheel studs in any way.
If the stud or nut is defective, it must be replaced.
Also, the force of the nut is reduced by vibration or if the surface against which the nut is pressed is covered with rust. But you can’t unscrew a rusted nut, and you can’t move a wheel disk by any force, and sometimes you have to heat up rusted nuts by welding or even cut off the studs by welding. Therefore, corrosion must also be fought in order to be able to replace the wheel. nine0005
Corrosion does more than weaken the wheel nuts. In the process of corrosion, cracks and depressions appear on the surface of the disk, thereby reducing the effective thickness of the part and weakening it. The smallest surface defect becomes a stress concentrator. Over time, cracks develop from the gaps. A regular wheel maintenance program usually includes derusting and painting the rims. After the rust has been removed (for example, by wire brushing or sandblasting), the disc should be inspected for signs of cracking or pitting (pitting).
If the corrosion is minimal, defects can be sanded down, the disc painted and reused, but if serious defects are found, the disc cannot be used. nine0005
A torque wrench measures the resistance to rotation of a nut. If the stud is new and there is a slight burr on the thread, the twist resistance will be slightly higher than expected. After the nut is unscrewed, the second time the tightening torque along the "clean" thread will be less than the first time.
When painting wheel rims, care must be taken not to get paint on the threads of the studs, because when tightening the nuts, the paint will create additional resistance, the torque wrench readings will be incorrect and the tightening force will be insufficient. The layer of paint on the surface of the disk in contact with the nut should not exceed 0.1 mm. A thicker layer of paint can weaken the friction forces and wheel fastening. Some mechanics bolt the wheels first and then paint the rims and nuts. In this case, the paint protects the exposed threads of the studs from corrosion.
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A large amount of rust on the threads of a stud or nut also creates additional resistance and results in incorrect tightening torque. This problem is sometimes helped by a few drops of oil applied to the corroded section of the thread. However, oil must be applied very carefully - if it gets on the seat of the nut on the disk, the friction force will weaken, the readings of the torque wrench during tightening will be incorrect and the risk of self-loosening of the nut will increase. This applies especially to wheels that are mounted on studs with conical nuts. However, many drivers do not wait for corrosion to appear on the threads, but always, when tightening the conical wheel nuts, carefully apply grease to the threads so that it does not get on the conical part of the nut and into the holes in the disk. nine0005
The surface of the nut adjacent to the disc can be damaged by play and shock when the machine is moving. Discs and studs are also damaged, and the studs can break off, and the disc often splits.
After making sure that the mounting of the wheels is in order, you can proceed to check the wheel bearings and ball joints.
It is clear that you can manually check the play only on a relatively small wheel.
One wheel should be jacked up (it is better to start from the front one) and shake it by the upper-lower edges, checking for play in the pivot or bearings. To determine the amount of backlash, you can use the indicator. Most manufacturers indicate the allowable backlash of the upper part of the wheel of trucks and trailers in the vertical plane of 0.25 ... 0.50 mm. Usually, an experienced mechanic can estimate the amount of play without using instruments, "by touch", shaking the wheel with his hands. nine0005
While the wheel is rocking, watch the brake cylinder - if it moves with the wheel, this is a sure sign of play in the kingpin. If the wheel moves by itself, then most likely there is play in the bearing.
In addition, you should check the play of the wheel in a horizontal plane by shaking it from the front to the back (grasp it with your hands at the 3 and 9 o'clock position on the dial). Movement indicates play in the ball joints of the steering rods. (But this is only if there is no play in the wheel bearings.) There are two rules to remember when starting this test: do not lubricate the parts to be checked before checking, because the grease will fill the gaps and you will not detect play. And secondly, if the air temperature is below -5 ° C, the grease will thicken, and you will not detect play either. nine0005
During the operation of the machine, all bearings wear out and sooner or later fail. If a worn bearing is not replaced in time, it can collapse in motion, which is very dangerous.
Bearings must be lubricated and adjusted regularly to prevent premature failure. The frequency of lubrication is determined by the machine manufacturer.
The adjustment interval is usually the same as the lubrication interval. But when adjusting, it should be remembered that a small play in tapered roller bearings (the value indicated above) is not only not harmful, but even desirable. It is acceptable even if the backlash exceeds the recommended value by 20 ... 50%. It is much worse if there is no play at all or the wheel bearing adjusting nut is tightened too much - this can lead to overheating and subsequent destruction of the bearings. nine0005
If the wheel bearings are extremely worn, you can almost always tell by the sound they make when they turn. Almost always, a worn bearing, before destruction, makes much more noise during operation than a serviceable bearing. The noise of worn wheel bearings is usually similar to a dull rustling. An experienced mechanic will always determine by sound whether the bearing is in good condition.
If a suspicious sound appears from the side of the wheel hubs, but it is not possible to accurately determine its causes and origin, do the following: jack up the wheels located on the same axle and rotate each of them in turn.
If one wheel makes much more noise during rotation than the other, there is a high probability that the hub bearings on it will soon become completely unusable. nine0005
The tire is perhaps the most expensive and at the same time wear part of the wheel. Tire rupture in motion is very dangerous. Therefore, it is necessary to always keep tires in good condition, repair and service them in a timely manner.
Tire maintenance basically consists of regularly checking and adjusting the air pressure in the tires. The air pressure in the tire should be maintained as recommended by the manufacturer, however, it should be borne in mind that in order to extend the life of the tire, it is better to overinflate it than underinflate it. A slight excess of air pressure, as a rule, does not lead to unpleasant consequences, but a low pressure significantly reduces the life of the tire. However, a significant excess of pressure reduces the stability and patency of any wheeled vehicle, so the pressure recommended by the manufacturer is the best option.
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Tire life of steer tires is significantly affected by tire alignment, so camber of steer tires should be checked regularly. Many car manufacturers recommend checking and adjusting steering wheel alignment every 5,000 km. If not properly adjusted, the tread can wear out very quickly - within a few hundred kilometers.
The driver must check the condition of the wheels before starting work and after the end of the shift. nine0005
• Check what can be seen with the naked eye: for distortion, runout, misalignment; Is the tire pressure sufficient? whether the wheel is rubbing against other parts of the machine - the frame, the wing. Look for signs of uneven wear on the tread or sidewalls, “bubbles” due to broken cords, and other defects. Are different tires installed in a pair, are all valve caps in place.
• Pay attention to all oil and fuel leaks - these fluids can damage tires. nine0005
• Check that the rims are not bent or otherwise damaged, and that there are no signs of the tire turning against the rim.
• All axles and wheels must be positioned (rotate) in the correct planes, suspension travel must also be in the correct planes. Deviations can cause tires to spin and slip, which of course shortens tire life, creates additional rolling resistance and increases fuel consumption.
• Remove any objects stuck in the tread and between the dual tires. nine0005
• Inspect tires for cuts or other defects. Off-road tires often have damage, but they are not always dangerous and impair its performance. If the damage is really serious, the tire should be replaced or repaired. Contact a qualified technician who can determine whether a damaged tire can be repaired or should be replaced. Holes from nails can be repaired as much as you like. There should be no more than two cuts. A hole in the tread pattern zone is allowed no more than 10 mm long. Repair options in the most stressed areas of the sidewalls are also limited. nine0005
• Do not weld or otherwise heat the rims near the mounted tyre.
Be sure to remove the tires before performing heat-related repairs to the rim.
• Before removing the rim of the inner or outer wheel, bleed the air from both dual tires.
• Never use a crane to lift tires with the hook hooked to the inside of the sidewall. Use flat straps that wrap around the tire from the outside.
• Do not use damaged tires or rims on steering axles.
• Replace tires early. It is unprofitable to operate tires until the groove depth reaches the limit value. It is recommended to leave about 5 mm of the pattern to the maximum depth so that the tire can be restored by welding.
• Store tires in a cool, dry place, out of direct sunlight, in an upright position, not stacked. nine0005
Can winter tires be used in summer?
When the weather turns to summer heat, both temperature and road conditions change. And although it seems quite logical to change the tires on the car when the season changes, not all drivers have time to do it on time.
Moreover, some believe that winter tires from European manufacturers are designed for the "European winter", which is supposedly soft, so that such tires can be used in Russia in the summer. Is this really true and what is the potential cost of a mistake? nine0005
How a winter tire differs from a summer tire
The differences are primarily due to the different conditions in which winter and summer tires operate, when it is required to provide maximum grip and driving stability, based on temperature and asphalt conditions. Therefore, there are differences in the production technology of winter and summer tires. An all-season tyre, which occupies an intermediate position between a summer and a winter tire, however, in the heat, it does not perform as well as a summer tire, and in a cold, not as well as a winter one. Thus, a pneumatic tire is a winter tire if the design of the tire, the rubber compounds used in its production, and the tread pattern are specially designed to guarantee increased grip on icy and snow-covered surfaces compared to a conventional summer tire.
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Winter tires must be marked with the symbols "M+S" or "M&S" or "M·S". The manufacturer of a winter tire, in addition to this mandatory marking, may apply an additional marking in the form of a snowflake against the background of a three-headed mountain peak:. This marking indicates that the winter tire is suitable for operation in severe winter conditions, including dense and packed snow, which is confirmed by the high results of special test tests. Tires with such a pictogram are usually considered real winter tires. The designation “M + S” on tires literally translates as “mud and snow”. The developers of such tires sought to improve the performance of such tires when driving on mud, freshly fallen or beginning to melt snow. Many all-season tires can carry this label, but not all that have it are tested as tires for severe winter conditions. So, a real winter tire always has the “M + S” marking and the snowflake icon against the background of three mountain peaks at the same time.
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Differences in the rubber composition of winter and summer tires
In the manufacture of various elements of the tire, rubber compounds of different properties and purpose are used.
Winter tire compounds must be such that the structural elements of winter tires retain their performance to the maximum extent in the temperature range characteristic of a particular climatic zone. Usually the range from positive 5 - 10°C to negative 40 - 45°C is implied. Unlike winter tires, the rubber compounds of summer tires must ensure the effective functioning of the tire at positive temperatures, up to 50 - 55°C. At a positive temperature close to 0°C, the functional characteristics of the rubber compounds of a summer tire noticeably decrease, and at negative temperatures they deteriorate sharply, which makes it very dangerous to use a summer tire in winter at a negative temperature. nine0005
Differences in tread pattern
Winter tires have a tread adapted to winter conditions.
It is deeper, its elements are larger, the structure itself is more sparse. Numerous lamellas (narrow sipes, the width of which is 5-10 times less than the width of the other tread grooves), oriented in different directions, increase the controllability and braking efficiency of the car on snow and ice, as well as increase the grip of the tire on the winter road and the braking efficiency of the car . Winter tire tread grooves are usually wider and deeper than summer tire tread grooves. Unlike a summer tire, the tread pattern of a winter tire should provide not only effective water drainage, but also the removal of a mixture of snow and water (snow-water sludge) from the contact patch of a winter tire with the road. In addition, the tread of some winter tires can be equipped with anti-skid studs, which provide increased grip on ice and packed snow. For any tire, the norm of the residual tread depth is set by law, upon reaching which the tire must be removed from service. The tire manufacturer must provide for the presence in the tread pattern of indicators that the tread wear limit has been reached, which help the driver to understand in a timely manner that the tread depth is the minimum permissible and the operation of such a tire should be immediately discontinued. For a winter passenger tire that is operated on an icy or snowy road surface, this rate is 4 millimeters. nine0005
The tread pattern of a summer tire is designed taking into account the specifics of tire operation in summer conditions, usually these are good roads, high speeds, increased requirements for driving comfort, economy and mileage of a summer tire, safety on wet roads. The number of sipes in the tread pattern of a summer tire is significantly less than that of a winter tire. The summer tire tread cannot be equipped with anti-skid studs. For a summer passenger tire, the legally established norm for the residual tread depth, upon reaching which the summer tire must be taken out of service, is 1.6 mm. nine0005
Effects of using a winter tire in summer
Winter tires have improved grip on snowy and icy roads. If you use winter tires on dry road surfaces, you may encounter a deterioration in vehicle handling, an increase in braking distances, an increased risk of aquaplaning, excessive heat generation in the tire, faster wear of the tread part of the winter tire, and a rather high level of noise generated by the tire.
Winter studded tires destroy dry pavement with their studs, thereby causing harm not only to the road itself, but also to the environment. Winter tires are usually heavier than summer tires of similar size, the groove depth and saturation of the sipes in the tread pattern are greater, which leads to the deterioration of such an important tire property as fuel efficiency for motorists. nine0005
The time when it is necessary to change tires
As for the procedure for using winter tires, it is defined in the technical regulation of the Customs Union "On the safety of wheeled vehicles" (abbreviated as TR CU), which was approved by the Commission of the Customs Union in 2011, and entered into effect in January 2015.
In particular, the TR CU establishes that in the winter period (December, January, February) it is forbidden to operate vehicles that are not equipped with winter tires, but in the summer period (June, July, August) it is forbidden to operate vehicles equipped with winter tires.
