It does not occur to pedestrians to wear shoes two or three sizes larger or smaller than their own, since it is completely impossible to walk in such shoes. At the same time, some drivers try to "put on" their car in unsuitable "shoes", and even then, after an accident at a turn in the road, they ask: "Why did it (the tire) jump off, huh?"
The corresponding tires are produced for each vehicle. In times of widespread scarcity, it was difficult to find any tire. Now this is not at all difficult to do. On sale there is huge assortment domestic and imported tires (only funds would allow). When buying new tires for your car, pay attention not only to their size, but also to other parameters. Tires must match the model exactly your hiscar.
There are usually no problems with the permissible load, since the safety margin modern tires very big. But, having found a tire lying around in the attic, first it is worth clarifying whether it is suitable for permissible load to your two-ton jeep.
5.5. Tires of various sizes, designs ( radial, diagonal, chamber, tubeless), models, with different tread patterns, studded and non-studded, frost-resistant and frost-resistant, new and remanufactured.
Let's go back to our shoes again. If you put on a boot on one leg that does not correspond to what you put on the other leg, then it will be, to put it mildly, uncomfortable to move both on snow and on parquet.
The effect can be felt by wearing a high-heeled shoe with a leather sole on one foot, and a flat shoe with a grooved rubber sole on the other. It is not difficult to imagine your state of mind while walking, as well as the reaction of others.
Jokes aside when it comes to safety! Both diagonal tires or both radial tires must be installed on one axle of the vehicle. Otherwise, due to the difference in characteristics of diagonal and radial tires, when driving, the car will necessarily "go away", and with intensive or emergency braking you will be guaranteed skidding. This is due to the fact that, while the bias tire is "stuck" on the road, the radial tire "spreads" on the asphalt. Accordingly, the wheels on the right and on the left will have a different coefficient of adhesion to the road, which will inevitably lead to the car moving to the side when driving and to its skid when braking.
The tread pattern of tires on one axle of the car must also be the same, otherwise, again, "dancing" on the road cannot be avoided. Your car will not move along the set trajectory, which is especially dangerous in heavy traffic and on slippery roads.
On a pair of front wheels of a car, it is allowed to have a tread pattern that differs from a pair of rear wheels. But in this case it is inconvenient to use the spare wheel. If one of the wheels is punctured, you will be forced to either break the law or carry two spare wheels with you, one for each pair.
These tips will help you replace your tires properly. We will talk about the advantages and disadvantages of replacing the base rubber sizes with alternative ones.
Tire replacement is performed in several cases, for example:
- the tire has become unusable due to wear
- improve running performance, reduce braking distances
- replacement due to the change of season
- saving money, because smaller sizes are cheaper
- improve the design of the car, due to a lowered profile, increased width or due to an unusual tread.
The most important criteria to consider when changing tires:
2. Vehicle manufacturers allow variations in wheel outer diameter in the range of 2% to 3.5%. Thus, if it is necessary to supply discs with a larger diameter, the ratio of width to profile height should be reduced in order for the absolute dimensions of the wheel to change within the normal range.
3. Also, before making changes to the design of the chassis of your car, you should remember that the manufacturer guarantees the appropriate running parameters vehicle, provided that the base wheel dimensions are used.
Advantages when installing larger tires:
- Improved grip. The degree of traction improvement depends largely on the ratio of the width to the height of the wheel. In addition, increasing the width of the tire shortens the braking distance on dry surfaces, due to the increased contact patch.
- Improved cornering response. For example, a larger rim diameter, combined with a lower profile height, increases the vehicle's cornering stability and also increases the speed at which you can safely enter a corner. Due to the lower profile, the rubber deforms much less.
- Improved appearance... Large discs and wide tires, as a rule, improve the appearance of the car (but, of course, without fanaticism).
- The ability to install increased brake discs, and, accordingly, calipers with a large number of pistons. This modification will significantly improve the efficiency of the braking system.
Disadvantages when choosing larger tires:
- Cost. New rims and new tires are always a significant expense, especially with larger rims. The same can be said about tires, because in order to increase the tread width and reduce the profile height, without qualitative changes, manufacturers are forced to use better materials and more sophisticated technologies, which in the end makes the final product more expensive.
- Increased fuel consumption. Wider tires have increased rolling resistance, which in turn increases the amount of fuel consumed.
- Rim and tire mass. If this position does not fall under the classification of "lightweight", this combination will adversely affect the acceleration of the vehicle.
- There is a high likelihood of tire and rim damage. With a decrease in the height of the rubber profile, the likelihood of damage to the rim or the tire itself increases when driving on poor-quality surfaces.
- Decreased comfort level. A lowered profile means a hardness uncharacteristic of a higher profile rubber.
- Increase in noise level. It depends on the shape and type of the tread, but increasing the width of the tire almost always leads to an increase in noise, as the air flow between the contact patch and the tread travels a greater distance.
- Reduced aquaplaning. Wide rubber with a low profile, has a larger contact patch, which in turn increases the amount of water that needs to be removed from under the wheels. Manufacturers try to compensate for this component with a directional herringbone tread pattern, or with asymmetric grooves that are independent of each other.
- Reduces grip on mud surfaces. An increase in the contact patch is directly proportional to an increase in stopping distance when it comes to mud or sandy landscapes.
In order to calculate the range of possible interchangeable dimensions, it is necessary to know the permissible nominal and actual dimensions of the wheel diameter as a whole. Wheel replacement options for your car can be found in next section of the site , or calculate using the special formula below:
2. Nominal rim diameter
3. Difference (subtract the nominal diameter of the rim from the outer diameter)
4. Add an average of 3% to the difference, we get the required value of the nominal tolerance.
Reducing the rim size
To install smaller wheels, motorists resort mainly to winter period... The calculation applies the same principles as discussed in the formula above. However, it is worth checking the size compatibility brake disc, caliper in relation to the smaller rim. It is believed that a smaller wheel width contributes to better grip in winter, because it provides more pressure per square centimeter of the contact patch.
And finally, remember that the declared specifications vehicle manufacturer's specifications are correct, provided that the recommended wheel and tire sizes are used.
Tire selection for your car depends on several criteria, the main of which are seasonality and disk sizeon which to put tire... Other important factors of choice are the maximum, speed characteristics, grip parameters with wet and dry surfaces, handling, comfort, resistance to aquaplaning and wear resistance.
Modern tires are one of the most technically complex products used in modern car... More than 40 components and dozens of chemical elements, complex chemical processes and a sophisticated testing system have created an entire industry, one of the most labor-intensive and science-intensive. First of all, remember that all efforts, directions, torques car-generated middle class to the road and back are transferred by means of 4 contact spots with a total area of \u200b\u200bno more than 2 A4 sheets! In fact, the entire passenger car tire industry, technology and marketing is aimed at understanding the processes that take place in these contact spots and translating them into the safe movement of your car. At the same time, of course, not forgetting about the aesthetic side of the issue, an effective tire should look beautiful.
Let's figure it out in order.
1. Seasonality
There are three types of tread pattern for passenger cars.
The first is tires with summer pattern tread (or road). The tread has many constituent elements that form longitudinal grooves and ribs. As a rule, there is no micro-drawing on them. These tires are designed for asphalt concrete roads with dry and wet surfaces and are of little use for driving on country roads, especially when wet. Moreover, they are not suitable for snowy roads in any condition.
Second - tires with universal pattern tread ( all-season). The grooves between the constituent elements are wide enough in the longitudinal and transverse directions. The protector also has a micro-pattern - narrow ("knife") slots. The universal pattern gives good grip on soft ground. Universal tires perform significantly better than summer tires on winter roads. However, on hard surfaces (asphalt concrete), the universal tread wears out 10-15% faster than the summer tread.
Third - tires with winter pattern tread, which is formed by individual blocks separated by wide grooves. The grooves account for 25-40% of the tread area. Winter tires have a wide range of tread types and shapes - from relatively smooth universal use (for cleared winter roads) to rough with developed lugs designed for snowy roads with ice. Winter tires are often studded. However, recently, especially in large cities, they have become very popular. winter tires, thornless, so called frictional or simply " velcro". What to choose - spikes or velcro? Tire experts say: "The choice of rubber type depends on the operating conditions." Frictional, studless rubber behaves more confidently on a snowy road and on asphalt, studded tires - good for icy surfaces, wet ice and porridge. But all “ thorns”, Regardless of the manufacturer, they rattle heavily and wear out quickly when driving on asphalt, so it is not recommended to put them ahead of time. Braking distances studded tire on asphalt versus non-studded increases by 5-7%, and on ice and ice the braking distance of the “thorns” decreases by 20-30% compared to the indicators friction rubber”.
2. Tire size
When choosing a tire size, you must select a standard size that is allowed by the vehicle manufacturer. What is rubber standard size? The standard size determines its geometric dimensions: width, height and diameter of the tire. For example, marking “ 205/65 R16"Means the following:
215 – tire width in mm;
65 – height (profile) of the tire as a percentage of the width (215 * 0.65 \u003d 140 mm);
R - the letter "R" indicates that the tire design is radial (if there is no letter "R", then the design is diagonal);
16 is the diameter of the rim in inches to which this tire should be installed.
All permitted sizes are indicated in the vehicle manual. Often the same information is duplicated on the fuel filler flap or in the driver's doorway. If you install rubber with a diameter larger than that allowed by the manufacturer (the outer diameter of the wheel turns out to be larger than for the permitted standard sizes), then the wheel will most likely cling to the wheel arches, which is very unsafe and leads to premature tire wear.
If you install more low profile rubberthan allowed, then the car will become excessively "stiff", and the suspension will "kill" much faster.
If you install tires with more high profilethan allowed, the vehicle's handling will deteriorate significantly. The handling will become "wadded", while at high speed there is a risk of the tire bouncing off the rim!
Low profile rubber makes driving more precise and sharp. It is easier for the driver to control the car on high speeds, especially in corners, therefore for active driving given type rubber will be preferable. It is worth remembering about back side medals - low profile rubber dampens all the bumps in the road worse, so the suspension will break much faster. If the roads in your area are "rich" in potholes, then you should think about choosing rubber with more high profile.
As opposed to low profile rubber, tires with a higher profile "swallow" flaws well enough road surfacewhile extending the life of the vehicle's suspension and providing sufficient driver comfort. If you are not a fan of thrills, fast and active driving, then this choice will be preferable for you.
For summer, it is preferable to choose more wide rubber , since this increases the contact patch with the road surface and, as a consequence, improves the dynamic characteristics of the car (the larger the contact patch, the greater the potential acceleration, both positive - acceleration and negative - braking). On the other hand, this choice will slightly increase fuel consumption - the larger the contact patch, the higher the rolling resistance. In addition, do not forget about overcoming puddles - the wider the rubber, the lower the speed begins aquaplaning.
As you can see selection of standard size of rubber is a rather non-trivial task, for the optimal solution of which many factors must be taken into account. However, for the average driver of a large metropolis, in most cases, the optimal choice will be, paradoxically, the average size from the number of combinations proposed by the car manufacturer. If wheel disks you already have, and you are not going to change them, then the problem of choosing a standard size of summer tires is reduced to a minimum, but at the same time it is worth remembering the advantages and disadvantages of such a choice.
Index permissible load (or index of carrying capacity, also called load factor) is a conditional parameter. Some tire manufacturers decipher it: the bus can be written in full Max Load (maximum load) and double digits in kilograms and imperial pounds.
Some models provide different tire loadmounted on front and rear axles. The load index is a number from 0 to 279, which corresponds to the load that the tire can withstand at the maximum internal air pressure. There is a special load index table, by which its maximum value is determined. For example, an index value of 105 corresponds to a maximum load of 925 kg.
4. Speed \u200b\u200bcharacteristics
Maximum speed recommended by the tire manufacturer can be deciphered speed index, which is printed on the sidewall of the tire. However, this index not only and not so much limits the maximum speed mode of the car on your tires... Maximum vehicle speed is limited road conditions, driver experience and many other factors. For example: incorrect pressure (especially low pressure) in tires drastically eliminates this indicator. The speed index, perhaps more indicates the stability of all qualities and characteristics given out by your tire up to a given speed (of course, with the correct recommended pressure). In other words - what speed index the higher the better, and the more effective the basic qualities of the tire (grip, comfort, wear resistance, resistance to aquaplaning) when driving at high speeds. Tires with a high speed index (they are 10-15% more expensive) are more suitable for drivers of active drive.
5. Parameters of adhesion to the surface
Dry grip. This indicator determines the braking or traction properties of the tire when driving on dry hard surfaces. This parameter is influenced by: the composition of the rubber mixture, the area of \u200b\u200bcontact of the rubber with the road (design closeness), the stability of the shape of the contact patch (depends on the tire design). The best way to assess this parameter is to study the results of objective tire braking tests published by authoritative publications.
Wet grip. Determined by the effectiveness of braking on a wet hard surface. Depends on the presence of a tread compound special additives, the presence of additional adhesion edges (lamellas), the stability of the shape of the contact patch. Objective tests are the best way to assess this parameter.
6. Controllability
Controllability - the property of the tire to follow the trajectory of the vehicle set by the driver, the information content of the steering reactions. This parameter is influenced by the shape of the tread pattern, the rigidity of its central zone and shoulder elements, and the composition of the rubber. For cornering, the stability of the shape of the contact patch is especially important, depending on the structure of the tire carcass and the presence of reinforcing layers-belts. The traditional solution to improve handling is a tread pattern with a solid center rib and closed shoulder blocks. The controllability of the tire is tested by analyzing the minimum time of passing the track of a simple closed trajectory, the nature of the vehicle skidding, and the ability to maintain a straight-line movement of the vehicle at high speeds.
7. Comfort
Comfort parameters are partly subjective (tire softness, ability to absorb small bumps) and objective (noise). Comfort parameters are influenced by: tire composition, carcass structure, tread pattern shape, arrangement of tread blocks with variable pitch, minimizing resonant sound vibrations.
8. Resistance to aquaplaning
One of the most dangerous phenomena when driving at high speeds is aquaplaning. The resistance of a tire to aquaplaning depends, first of all, on the degree of openness of the closed tread, i.e. the presence of the required number of drainage channels, their shape, depth and direction. Most notable feature rain tire - a characteristic directional tread pattern with a large number of curved turbo channels from the center of the tire to the edge, serving to drain water from under the contact patch. Given the safety impact of the tire's aquaplaning resistance, many tire manufacturers separated rain tires into a separate segment (subclass), assigning them characteristic names (for example - Uniroyal). The test for the tire's resistance to aquaplaning includes determining the boundary speed of the beginning of aquaplaning when driving on a specially prepared site, covered with an 8-10 mm layer of water when driving in a straight line and in a turn (or along a circular path). No less interesting are laboratory studies that determine the change in the shape and area of \u200b\u200bthe contact patch when driving at different speeds. The tire's resistance to aquaplaning is significantly affected by the residual tread depth. For this reason, self-respecting manufacturers test both new tires and those with 40-60% worn out tread.
9. Wear resistance
Tire wear primarily depends on the operating conditions of the tire: the nature and style of driving, the state of the suspension elements of cars (shock absorbers, hub bearings, ball bearings), the correct alignment of the wheels (camber-toe), the road surface and, of course, the pressure in bus. Deterioration of any of these parameters drastically reduces possible mileage tires. In terms of tire technology, we are talking about the tread wear resistance or wear rate. This parameter directly determines the number of kilometers your tire has traveled to maximum wear, all other things being equal tire operating conditions. The parameters affecting the tire wear resistance are as follows: openness of the tread - the more open the tread, the less rubber in the contact zone, and, accordingly, the greater the specific pressure and wear rate; the composition of the tread rubber (the presence of special additives), the structure of the tire carcass, which allows the most effective stabilization of the shape of the contact patch in motion.
10. How to choose tires for SUVs and crossovers?
Most tire manufacturers are increasingly focusing on the growing segment SUV... That is why every company has a new winter crossover model in its arsenal. It should be borne in mind that they are designed for urban use, that is, they combine characteristics such as good grip on asphalt and stable behavior on ice and snow. And they differ from passenger car tires in dimension and load index. However, in order to drive on suburban roads, this is not enough, therefore, if the plans include the conquest of snow-covered fields and impassable forests, it is necessary to choose tires with special characteristics, since such models are also not uncommon. There are, of course, very radical measures - chains. They can be installed not on all wheels, but only on the drive axle. The cost of such armor is 7-9 thousand rubles, and the benefits can sometimes be simply invaluable.
11. An illustrative example of the arrangement of markings on the bus
Tire Load Index - conventional numerical designation that shows what mass load the tire can withstand in long-term operation. This information is necessary in order to choose the right tires, and thereby ensure a safe and comfortable ride on the car. To decipher the tire load index, a table is used, which shows the numerical designations of the index and the normal values \u200b\u200bof the mass that corresponds to them. Below we will give you such a table, as well as give information about speed index, which is also important when choosing a tire. The rest of the information about the designations on the tires, you can.
Load value (MAX LOAD) and tire pressure
Determination of the load index
First of all, it must be remembered that the numerical values \u200b\u200bof the load index given on the tires are conditional! That is, these numbers do not mean absolute maximum massthe tire is designed for. As the load index increases, so does the maximum allowable weight of the machine for which it is designed.
However, in the application plan of many drivers when buying new rubber interested in a simple question - which tire load index to choose in one case or another? It's easy to answer. There are two options. The first one is to ask about the relevant information in the manual for your car or in reference books. Many automakers directly indicate information that for a specific model a tire with such and such a load index is needed (the same applies to the speed index, although the selection is easier there, but more on that later). The second option is to do the calculations yourself.
Load index for passenger cars can be calculated based on the unladen weight of the machine at maximum load. That is, to the mass of the equipped vehicle (with a fully fueled fuel tank, process fluids, repair kit, spare wheel, and so on) weight is added maximum number people who fit in it (for passenger cars usually it is 5), as well as a certain mass of additional cargo (here it all depends on the specific car, for small cars it can be 100 ... 200 kg, and for SUVs - over 500 kg). Approximate value of indices for different types cars:
- 60 - load up to 250 kg - for A-class cars;
- 68 - up to 315 kg per wheel - for B-class representatives;
- 75 - 387 kg per wheel - for C-class cars;
- 87 - 545 kg load - for minivans and crossovers;
- 99 - 775 kg - for SUVs and light commercial vehicles.
Further, the resulting maximum mass must be divided by four (for traditional cars with four wheels). And after that add 35 ... 40% of the stock. Having carried out such simple calculations, you will get the absolute value in kilograms that the tire must withstand. The final stage is the choice of the symbol for the load index of the machine according to the table. Note that you must select the factor corresponding to the closest HIGHEST absolute value.
In order not to bother with calculating the load index required for the tires of your car, it is possible to quickly calculate everything on a special calculator. He will immediately give you the required number.
Often, stores already have several options for specific car models, from which you can choose the most suitable for you in terms of quality, price and manufacturer.
Actually make a stock for rear wheels especially if you often carry heavy loads. However, do not be zealous and choose tires with a too high index. The fact is that the more load the tire is designed for, the more rubber is used for its manufacture. Accordingly, such a tire will be heavier, and hence the three negative factors.
First, the engine will have to spend extra effort (and hence fuel!) To turn a heavy wheel. Second - a heavy tire will be very stiff, so it will be uncomfortable to ride on it. Third, with heavy tires, the suspension of the car experiences additional stress, which means that its normal operation is reduced.
Next, we present for you the promised table that will help you decipher the tire load index (here you will find the values \u200b\u200bfor tires for all types of cars - cars, SUVs, trucks, and so on). For passenger cars and SUVs, tires with an index value of 60 to 125 are used (respectively, from A-class cars to heavy SUVs).
| Load index | Maximum weight, kg | Load index | Maximum weight, kg |
| 0 | 45 | 100 | 800 |
| 1 | 46,2 | 101 | 825 |
| 2 | 47,5 | 102 | 850 |
| 3 | 48,7 | 103 | 875 |
| 4 | 50 | 104 | 900 |
| 5 | 51,5 | 105 | 925 |
| 6 | 53 | 106 | 950 |
| 7 | 54,5 | 107 | 975 |
| 8 | 56 | 108 | 1000 |
| 9 | 58 | 109 | 1030 |
| 10 | 60 | 110 | 1060 |
| 11 | 61,5 | 111 | 1090 |
| 12 | 63 | 112 | 1120 |
| 13 | 65 | 113 | 1150 |
| 14 | 67 | 114 | 1180 |
| 15 | 69 | 115 | 1215 |
| 16 | 71 | 116 | 1250 |
| 17 | 73 | 117 | 1285 |
| 18 | 75 | 118 | 1320 |
| 19 | 77,5 | 119 | 1360 |
| 20 | 80 | 120 | 1400 |
| 21 | 82,5 | 121 | 1450 |
| 22 | 85 | 122 | 1500 |
| 23 | 87,5 | 123 | 1550 |
| 24 | 90 | 124 | 1600 |
| 25 | 92,5 | 125 | 1650 |
| 26 | 95 | 126 | 1700 |
| 27 | 97 | 127 | 1750 |
| 28 | 100 | 128 | 1800 |
| 29 | 103 | 129 | 1850 |
| 30 | 106 | 130 | 1900 |
| 31 | 109 | 131 | 1950 |
| 32 | 112 | 132 | 2000 |
| 33 | 115 | 133 | 2060 |
| 34 | 118 | 134 | 2120 |
| 35 | 121 | 135 | 2180 |
| 36 | 125 | 136 | 2240 |
| 37 | 128 | 137 | 2300 |
| 38 | 132 | 138 | 2360 |
| 39 | 136 | 139 | 2430 |
| 40 | 140 | 140 | 2500 |
| 41 | 145 | 141 | 2575 |
| 42 | 150 | 142 | 2650 |
| 43 | 155 | 143 | 2725 |
| 44 | 160 | 144 | 2800 |
| 45 | 165 | 145 | 2900 |
| 46 | 170 | 146 | 3000 |
| 47 | 175 | 147 | 3075 |
| 48 | 180 | 148 | 3150 |
| 49 | 185 | 149 | 3250 |
| 50 | 190 | 150 | 3350 |
| 51 | 195 | 151 | 3450 |
| 52 | 200 | 152 | 3550 |
| 53 | 206 | 153 | 3650 |
| 54 | 212 | 154 | 3750 |
| 55 | 218 | 155 | 3875 |
| 56 | 224 | 156 | 4000 |
| 57 | 230 | 157 | 4125 |
| 58 | 236 | 158 | 4250 |
| 59 | 243 | 159 | 4375 |
| 60 | 250 | 160 | 4500 |
| 61 | 257 | 161 | 4625 |
| 62 | 265 | 162 | 4750 |
| 63 | 272 | 163 | 4875 |
| 64 | 280 | 164 | 5000 |
| 65 | 290 | 165 | 5150 |
| 66 | 300 | 166 | 5300 |
| 67 | 307 | 167 | 5450 |
| 68 | 315 | 168 | 5600 |
| 69 | 325 | 169 | 5800 |
| 70 | 335 | 170 | 6000 |
| 71 | 345 | 171 | 6150 |
| 72 | 355 | 172 | 6300 |
| 73 | 365 | 173 | 6500 |
| 74 | 375 | 174 | 6700 |
| 75 | 387 | 175 | 6900 |
| 76 | 400 | 176 | 7100 |
| 77 | 412 | 177 | 7300 |
| 78 | 425 | 178 | 7500 |
| 79 | 437 | 179 | 7750 |
| 80 | 450 | 180 | 8000 |
| 81 | 462 | 181 | 8250 |
| 82 | 475 | 182 | 8500 |
| 83 | 487 | 183 | 8750 |
| 84 | 500 | 184 | 9000 |
| 85 | 515 | 185 | 9250 |
| 86 | 530 | 186 | 9500 |
| 87 | 545 | 187 | 9750 |
| 88 | 560 | 188 | 10000 |
| 89 | 580 | 189 | 10300 |
| 90 | 600 | 190 | 10600 |
| 91 | 615 | 191 | 10900 |
| 92 | 630 | 192 | 11200 |
| 93 | 650 | 193 | 11500 |
| 94 | 670 | 194 | 11800 |
| 95 | 690 | 195 | 12150 |
| 96 | 710 | 196 | 12500 |
| 97 | 730 | 197 | 12850 |
| 98 | 750 | 198 | 13200 |
| 99 | 775 | 199 | 13600 |
The designations of the load index and tire speed on the side surface of the rubber are next to each other. And this is not without reason, since they are interconnected. Unlike the load, the speed index is designated by letters of the Latin alphabet (from A to Z). For example, you can find on the tire the values \u200b\u200b92S or 88T, which will be the combined designation of the two mentioned indices.
The speed index is specially placed next to the load index. This information gives an idea of \u200b\u200bhow. what kind of load the tire can withstand at its maximum speed.
Deciphering the tire speed index is very simple. The closer the letter is to the end of the alphabet, the higher the speed the tire is designed for. The only exception is the letter H, located between U and V. So, we give you a similar table with which you can clarify what maximum speed this or that tire is designed for.
| Maximum speed, km / h | |
| A | 40 |
| B | 50 |
| C | 60 |
| D | 65 |
| E | 70 |
| F | 80 |
| G | 90 |
| J | 100 |
| K | 110 |
| L | 120 |
| M | 130 |
| N | 140 |
| P | 150 |
| Q | 160 |
| R | 170 |
| S | 180 |
| T | 190 |
| U | 200 |
| H | 210 |
| V | 240 |
| W | 270 |
| Y | 300 |
| VR | >210 |
| ZR | >240 |
| (W) | >270 |
| Z | >300 |
How to choose load and speed indices
Decoding of load and speed indices
European regulations ECE-R54 mandate all tire manufacturers to apply load and speed index values \u200b\u200bto them. In this case, the load index is usually indicated single installation wheels per axle on one side. If the rubber can be used for dual installation, then two values \u200b\u200bare indicated with a dash. For example, 102 / 100R. The first number is for a single installation, the second is for a double installation. Tires have this double designation. commercial class, which, in accordance with the same rules, can be installed not only on cars, but also on small trucks and vans (that is, on commercial vehicles). Such tires are additionally designated with the letter C or the word Commercial.
Do not install tires on cars with load and speed indexes lower than prescribed in the documentation.
As for the speed index, it not only affects the maximum permissible speedthe tire is designed for. The fact is that you cannot go for a long time (more than half an hour) on this very maximum speed... This is due to excessive tire wear. In addition, it is life-threatening, because at high speeds the rubber must work in normal and not critical modes. Therefore, it is allowed to drive for a long time at speeds 10 ... 15% lower than the maximum permissible. Especially such reasoning is relevant for bad roads, when rubber constantly falls into pits, potholes and bumps.
Do not exceed speed mode and do not drive for a long time at the maximum permissible speed for rubber.
When choosing rubber according to the speed index, as in the case of the load, you cannot choose very “high-speed” tires. The fact is that the higher the speed the tire is designed for, the softer it is. Accordingly, it will have better and more reliable grip on the road surface. However, this much wears out faster (remember how often tires are changed in Formula 1 races). That is why it is not recommended to buy very high-speed tires for ordinary cars used in urban environments.
Outcome
We are sure that the above information will help you understand what the load and speed indices of the tires mean, whose designations are located behind the tire size value. This will help you do right choice... At the same time, do not forget to leave a small margin of 10 ... 20% for both indices in order to ensure your driving comfort and safety on the road.
Do you want to choose a tire for your car, but don't know much about tire labeling? It's not a problem! In this section, we will help you figure out: what are the parameters of the tire, what they mean, and what kind of tire is suitable for your car.
Find tires / tire catalogDecoding of tire marking.
195/65 R15 91 T XL
195 is the width of the tire in mm.
65 - Proportionality, i.e. the ratio of the height of the profile to the width. In our case, it is equal to 65%. Simply put, with the same width, the larger this figure, the higher the tire will be and vice versa. Usually this value is called simply - "profile".
Since the tire profile is a relative value, it is important to take into account when selecting tires that if instead of 195/65 R15 you want to put tires with 205/65 R15, then not only the width of the tire will increase, but also the height! Which is unacceptable in most cases! (except for the cases when both of these standard sizes are indicated in the car manual). Accurate change data external dimensions wheels you can calculate in a special tire calculator.
If this ratio is not indicated (for example, 185 / R14C), then it is equal to 80-82% and the tire is called full-profile. Reinforced tires with such markings are usually used on vans and light trucks, where a high maximum wheel load is very important.
R - means a tire with a radial cord (in fact, now almost all tires are made this way).
Many people mistakenly think that R- stands for the radius of the tire, but this is precisely the radial design of the tire. There is also a diagonal design (denoted by the letter D), but recently it has practically not been produced, since its performance is much worse.
15 - wheel (disk) diameter in inches. (It is the diameter, not the radius! This is also a common mistake). This is the "landing" diameter of the tire on the disc, i.e. this is inner size tires or outer at the disk.
91 - load index. This is the maximum permissible load per wheel. For passenger cars, it is usually done with a margin and when choosing tires is not a decisive value, (in our case, IN - 91 - 670 kg.). For minibuses and small trucks, this parameter is very important and must be observed.
Tire Load Index Table:
T - tire speed index. The larger it is, the more more speed you can ride this tire (in our case IS - N - up to 210 km / h). Speaking about the tire speed index, I would like to note that with this parameter the tire manufacturer guarantees normal work rubber with constant movement of the machine at the specified speed for several hours.
Speed \u200b\u200bIndex Table:
American tire markings:
There are two different markings american tires... The first one is very similar to the European one, only the letters "P" are placed in front of the standard size (Passanger - for passenger car) or “LT” (Light Truck - light truck). For example: P 195/60 R 14 or LT 235/75 R15. And another tire marking, which is fundamentally different from the European one.
For instance: 31x10.5 R15 (corresponds to European standard size 265/75 R15)
31
is the outer diameter of the tire in inches.
10.5
- tire width in inches.
R - radial tire (older models of tires were diagonal).
15
is the inner diameter of the tire in inches.
Generally speaking, apart from the unusual inches, the American tire marking is logical and more understandable, unlike the European one, where the tire profile height is variable and depends on the tire width. And here everything is simple with the decoding: the first digit of the standard size is the outer diameter, the second is the width, the third is the inner diameter.
Additional information indicated in the marking on the sidewall of the tire:
XL or Extra Load - a reinforced tire, the load index of which is 3 units higher than that of conventional tires of the same standard size. In other words, if a load index of 91 is indicated on a given tire, marked XL or Extra Load, it means that with this index, the tire is able to withstand a maximum load of 670 kg instead of 615 kg (see the table of tire load indices).
M + S or M&S tire marking (Mud + Snow) - mud plus snow and means that the tires are all-season or winter. Many summer SUV tires are labeled M&S. However, these tires cannot be used in winter timesince winter tires have a completely different rubber composition and tread pattern, and the M&S badge indicates a good cross-country performance of the tire.
All Season or AS all-season tires. Aw (Any Weather) - Any weather.
Pictogram * (snowflake) - rubber is designed for use in harsh winter conditions. If the sidewall of the tire does not have this mark, then this tire is intended for use in summer conditions only.
Aquatred, Aquacontact, Rain, Water, Aqua or pictogram (umbrella) - special rain tires.
Outside and Inside; asymmetrical tires, i.e. it is important not to confuse which side is external and which is internal. When installed, the Outside lettering should be on the outside of the car, and Inside on the inside.
RSC (RunFlat System Component) - runFlat tires - these are tires on which you can continue to drive a car at a speed of no more than 80 km / h with a FULL drop in tire pressure (in case of a puncture or cut). On these tires, depending on the manufacturer's recommendations, you can drive from 50 to 150 km. Different manufacturers Tires use different designations of RSC technology. For example: Bridgestone RFT, Continental SSR, Goodyear RunOnFlat, Nokian Run Flat, Michelin ZP, etc.
Rotation or an arrow on the sidewall of the tire indicates a directional tire. When installing the tire, the direction of rotation of the wheel indicated by the arrow must be strictly observed.
Tubeless - tubeless tire... In the absence of this inscription, the tire can only be used with a camera. Tube Type - means that this tire must be used only with a tube.
Max Pressure; the maximum allowable tire pressure. Max Load - the maximum permissible load on each wheel of the vehicle, in kg.
Reinforced or the letters RF in the standard size (for example 195/70 R15RF) mean that this is a reinforced bus (6 layers). The letter C at the end of the standard size (for example 195/70 R15C) means truck tire (8 layers).
Radial This marking on a rubber in a standard size means that it is a tire of a radial design. Steel means there is a metal cord in the tire construction.
Letter E (in a circle) - the tire meets the European ECE (Economic Commission for Europe) requirements. DOT (Department of Transportation - US Department of Transportation) - American quality standard.
Temperature A, B or C heat resistance of tires at high speeds on a test bench (A is the best indicator).
Traction A, B or C - the ability of the tire to brake on a wet road surface.
Treadwear; the relative expected kilometers traveled compared to the US specific standard test.
TWI (Tread Wear Indiration) - indicators of tire tread wear indicators. The TWI wheel can also be marked with an arrow. The gauges are evenly spaced at eight or six places around the tire circumference and indicate the minimum tread depth allowed. The wear indicator is made in the form of a protrusion with a height of 1.6 mm (minimum tread for light vehicles) and is located in the groove of the tread (usually in the drainage grooves).
DOT - Coded manufacturer address, tire size code, certificate, production date (week / year).
