Tires are, without exaggeration, one of the most important active elements of car safety. They are always in operation, they are always loaded not only with the mass of the vehicle, but also with the road profile, they are especially important while driving, but they perform the functionality assigned to them even when the car is stationary. It is difficult to overestimate their contribution to safety, but almost all motorists underestimate their qualities. And very in vain. So close to the accident.
Many quality articles have been written about tire labeling on the Internet. Explanation of various designations, which include various parameters that tell the buyer from the direction of installation of the tire, date of issue and model, to maximum pressure, tire design, tire type (“winter”, “summer”), its dimensions and, of course, the index speeds and loads:
We will discuss the last two indicators now.
Summer resident about tires: why is it so important not to overload the car?
The summer season is about to begin. Soon, strings of owners of suburban property will stretch out of town. Many are in cars. Spring is a very important time of the year for a thoughtful gardener and gardener, and the house needs cosmetic repairs after the cold season. So it turns out that cars moving from the city on weekends are often loaded to the very roof. It happens that people do not know the measure and overload their cars.
Overloading has an extremely negative effect on the entire structure of the vehicle, but tires suffer the most because of it (heavy truck drivers know this firsthand). If the metal can survive such a mockery several times a year (the body will definitely not lead), then the tire can be damaged at any time, and, worst of all, even a new one. After all, the load is exceeded, which means that the manufacturer no longer gives you any guarantee that the worst will not happen.
Tires start to get very hot, cracks may appear along the bead ring, tire sidewall ruptures, hernias (bulges on the side of the tire), damage to the tire cord.
The result in this case will be very unpleasant.
If you're lucky, the tire will simply become unusable after serving a few seasons (less than its due date) and you will throw your money in the trash ().
In the worst case, the destruction of the tire will occur directly on the road. It is unlikely that the wheel will explode, but it can be quickly lowered due to damage. A particularly dangerous scenario involves damage to one of the front wheels.
What to do to avoid problems due to overload?
The answer, of course, is obvious - do not overload the machine. The manufacturer writes the load index for their products, here is the transcript in the table:
But you won't weigh all the luggage and passengers, will you? How to determine the possibility of overload by eye?
If you think that you won’t be able to exceed the maximum kilograms, think again at the moment when, having seated four passengers in the cabin, stuffing the trunk with the tools and luggage you need for the house, and also throwing a few bags on the roof (if you are a true summer resident, then you probably have a roof rack) you will get something like this picture:
In this case, you should split the transportation of things into several trips.
In other words, if you see that the suspension has sagged and the tires at nominal pressure have flattened a little in relation to how they were without load, there is a possibility of an overbalance.
And if expensive, high-quality tires are likely to be able to pass this torture without loss, then more budgetary narrow tires may well collapse due to excessive load.
Therefore, evaluate the workload of the car soberly.
To the “racer” about tires: why it is impossible to exceed the maximum speed?
The second equally important index is an indicator of maximum speed:
The indicator is important for the second category, which usually wakes up after hibernation - "racers", well, or street racers, as they like to call themselves. Young people who love high speeds, tuning and adrenaline.
Next to the tire size, on board the tire, such a parameter as the speed index is also marked. It is denoted by a Latin letter, from A to Z. Accordingly, the initial letter of the alphabet indicates the lowest speed, the last - the highest. Thanks to the table, you can find out the decoding of the speed value.
It is very easy to determine the excess of indicators in this case - according to the speedometer. But there are a couple of nuances.
1. It is important not to make a mistake with the speed index when buying. Do not be lazy to look at it on the sidewall of the tire. Not necessarily a wide tire with a low profile will have a high speed index. Especially some Chinese manufacturer. It is important to understand what materials it is made of, hence its strength will be clear.
Remember that the forces acting on the rubber while the car is moving are catastrophically huge. They grow in geometric proportion with a set of speed and it is absolutely impossible to neglect them!
2.Add 15 km/h to your vehicle's top speed when choosing a tire. It is unlikely that you will ever accelerate your car to the "maximum speed", but it is still better to have a margin of safety in this case. Your car accelerates to 170 km / h? Take tires with an indexT and so on.
3. If you have increased the power of the machine, replace the tires as well. This is also important to remember. The conclusion suggests itself from the first two points.
If you do not take into account these nuances, the following opportunity may happen:
Only here a pro was behind the wheel, are you also an equally skilled autopilot?
And you pay attention to such a characteristic of the tire as the load index. The safety of your ride depends on the selected load index. If for some reason the tire breaks while driving, especially on a slippery surface or at high speed, the car may lose control and this will lead to disaster.
I'll start right away with an example. Take a balloon, inflate it, and then squeeze it hard. burst? If not, they squeezed it weakly; if it did burst, they squeezed it hard. These terms refer to the load on the tire. If a one-year-old child sits on the ball, he may not become anything, and if a stocky man sits down, he will definitely burst, because the allowable load on the ball has been exceeded.
The wheel is still more complicated, because not only is it under pressure, it is also spinning. The more pressure is exerted on the wheel, the greater the load begins to experience the side of the wheel (the part that scurries against the curbs). If the permissible load is exceeded, the cord threads will begin to be damaged and a “hernia” will come out at the wheel, which looks like a bump. If a hernia has come out, it is no longer possible to ride on such a wheel. Firstly, it will no longer spin smoothly, and there will be vibration while driving, and secondly, the tire can collapse at any time.
How to choose a load index
I select the load index based on the maximum mass of my car divided by four. If the car weighs 1400 kg, and I can fill it with 60 liters of gasoline, load 120 kilograms of luggage, and put five people (including sleep) weighing 120 kilograms, then the maximum weight of my car will be 2180 kilograms, or 545 kilograms per wheel, which corresponds to an index of 87, however, if I really plan to drive with such a load, I need to create a reserve, and raise the index by a couple of points, i.e. choose an index of 89, which corresponds to 580 kilograms per wheel.
Maximum load or overload
If the estimated mass of the car has approached the limit mark, or crossed it, and the trip cannot be postponed by any means, drive in compliance with all safety rules. First of all, drive at a speed at which you are guaranteed to be able to keep the car when the wheel is destroyed, and secondly, be prepared for trouble. If you can’t drive slowly, but you don’t want trouble, divide the load into parts, or get rid of unnecessary things on the trip.
Table of tire load indices and their corresponding masses
| indus | Load, kg | indus | Load, kg | indus | Load, kg | indus | Load, kg |
| 50 | 190 | 70 | 335 | 90 | 600 | 110 | 1060 |
| 51 | 195 | 71 | 345 | 91 | 615 | 111 | 1090 |
| 52 | 200 | 72 | 355 | 92 | 630 | 112 | 1120 |
| 53 | 206 | 73 | 365 | 93 | 650 | 113 | 1150 |
| 54 | 212 | 74 | 375 | 94 | 670 | 114 | 1180 |
| 55 | 218 | 75 | 387 | 95 | 690 | 115 | 1215 |
| 56 | 224 | 76 | 400 | 96 | 710 | 116 | 1250 |
| 57 | 230 | 77 | 412 | 97 | 730 | 117 | 1285 |
| 58 | 236 | 78 | 425 | 98 | 750 | 118 | 1320 |
| 59 | 243 | 79 | 437 | 99 | 775 | 119 | 1360 |
| 60 | 250 | 80 | 450 | 100 | 800 | 120 | 1400 |
| 61 | 257 | 81 | 462 | 101 | 825 | 121 | 1450 |
| 62 | 265 | 82 | 475 | 102 | 850 | 122 | 1500 |
| 63 | 272 | 83 | 487 | 103 | 875 | 123 | 1550 |
| 64 | 280 | 84 | 500 | 104 | 900 | 124 | 1600 |
| 65 | 290 | 85 | 515 | 105 | 925 | 125 | 1650 |
| 66 | 300 | 86 | 530 | 106 | 950 | 126 | 1700 |
| 67 | 307 | 87 | 545 | 107 | 975 | 127 | 1750 |
| 68 | 315 | 88 | 560 | 108 | 1000 | 128 | 1800 |
| 69 | 325 | 89 | 580 | 109 | 1030 | 129 | 1850 |
| 130 | 1900 | ||||||
It is often necessary to know how to choose the right tires according to the load they must withstand during operation. This parameter in the characteristics of tires is called the load index of car tires. When choosing "shoes" for your iron horse, it is difficult to immediately identify this parameter. But this task seems difficult only at first glance, because such indicators as the load indices of car tires and the speed index are easily determined based on the marking on the tire itself, applied by the manufacturer.
According to the accepted marking rules, on the side surface of each tire there are symbols by which you can easily determine which tire load index to choose. This information determines all the characteristics of the product, but we are currently only interested in which tire load index to choose in our particular case. Each tire has a load limit, that is, how much weight a loaded vehicle must not exceed in order to use that tire. Where can you find this indicator? This is a two-digit number, which is located immediately after the standard size.
For example, 175 / 65R17 is the size, and after it, for example, the number 100 indicates a load of 800 kilograms. To determine exactly which load the figure corresponds to, there is a special correspondence table, according to which you can easily find information in a particular case. Some may think that it is enough to take the maximum permissible load in kilograms from the table, multiply by 4 wheels, to get the weight that a car with a load can have.
This is a delusion that can lead to very unpleasant events. It is known that any device or part has its own load limit. But at the same time, it is impossible to operate, whatever it is at maximum loads. Accordingly, when choosing tires, you need to add 20 percent to the calculated indicator. And then if you have an ordinary sedan, even a station wagon. But if you are the owner of an SUV, then it would be useful to add 30 percent, because. loads from an SUV, given their operating conditions, are somewhat higher than usual.
It would seem that this is all, and we know how to calculate the tire load index. But it turns out not. There is another interesting concept that experienced drivers know about. This is a spread. After all, everyone understands that each axle of the car carries a different weight. An empty car carries approximately the same load on the axles with a slight advantage on the front. But the loaded one is not so at all. The rear axle takes on 70%, and the front axle gets the remaining 30. This indicator is quite difficult to determine and there are no such tables by which it can be calculated. Here the driver must figure out for himself what kind of cargo he is transporting, how often the car is operated with a large load. And choose your tires accordingly.
If you play it safe and take it with a margin of safety, then you need to take into account several of the following facts. First, tires designed for heavy loads have a thicker layer of rubber, and this is extra weight. Secondly, these tires are more rigid, which entails extra noise while driving. Thirdly, the increased rigidity of the rubber reduces the damping properties and, accordingly, the suspension parts suffer. In addition, with all the variety of tires with the same load index, there are tires with different speed index. It is indicated by the letter of the Latin alphabet, and you can find it next to the above-discussed indicator of the tire load index.
An example of such designations is the letter J, which tells us that the tire can be operated at a speed of 100 km / h. The letter P means that you can risk breaking the speed limit up to 160 km / h. Well, if you see two letters at once in the speed index, then these are "tires for Schumacher." They can reach over 200 km/h. As with the previous indicator, it must be recalled that these are also marginal indicators and it is better not to even try to test them for reliability. That, it seems, is all that concerns these two main indicators in the characteristics of tires. Everyone chooses for himself what and how to exploit. But, if you have a passport for your car model, then it is best to look into it and not bother with the choice, but take what the manufacturer recommends.
Tire load index- a conditional 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 thus 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. Next, we will give you such a table, as well as give information about speed index, which is also important when choosing a tire. You can find the rest of the information about the designations available on tires.
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 the absolute maximum weight for which the tire is designed. As the load index increases, the maximum allowable weight of the machine for which it is designed also increases.
However, in terms of application, many drivers are interested in a simple question when buying new tires - which tire load index to choose in one case or another? It is easy to answer it. There are two options. The first is to ask for the relevant information in the manual for your car or in the reference literature. Many automakers directly indicate the information that a particular model needs a tire with such and such a load index (the same applies to the speed index, although 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 empty weight of the machine with the maximum load. That is, to the mass of the equipped vehicle (with a fully filled fuel tank, process fluids, repair kit, spare wheel, and so on), the mass of the maximum number of people placed in it is added (for cars usually it is 5), as well as some mass of additional cargo (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 of 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 machines 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 a symbol for the load index of the machine according to the table. Please note that you must select the coefficient corresponding to the nearest HIGHEST absolute value.
In order not to bother with the calculations of the load index required for the tires of your car, it is possible to quickly calculate everything on a special calculator. It will immediately give you the required number.
Often, for specific models of cars in stores, there are already several options, from which you can choose the most suitable for you in terms of quality, price and manufacturer.
Keep stock up to date for rear wheels especially if you often carry heavy loads. However, do not be zealous and choose tires with an index that is too high. 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 arises three negative factors.
The first is that the engine will be forced to expend additional effort (and hence fuel!) To rotate the heavy wheel. The second is that a heavy tire will be very stiff, so it will be uncomfortable to ride on it. The third - with heavy tires, the suspension of the car experiences an additional load, which means that its normal operation period is reduced.
Next, we give you the promised table that will help you decipher the tire load index (here you will find tire values \u200b\u200bfor all types of cars - cars, SUVs, trucks, and so on). For cars and SUVs, tires with an index value from 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 lateral surface of the rubber are located nearby. And this is no accident, because they are interconnected. Unlike the load, the speed index has a letter designation in Latin letters (from A to Z). For example, you can find the values 92S or 88T on the tire, which will just 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. what kind of load can the tire 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 more 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
Deciphering load and speed indices
European regulations ECE-R54 require all tire manufacturers to put load and speed index values on them. In this case, the load index is usually indicated for single installation wheels on an axle on one side. If the rubber can be used for a double installation, then two values \u200b\u200bare indicated through a dash. For example, 102/100R. The first number is for a single installation, the second is for a dual installation. Tires have such a 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, commercial vehicles). Such tires are additionally indicated by the letter C or the word Commercial.
It is impossible to install tires with load and speed indexes lower than those prescribed in the documentation.
As for the speed index, it does not only affect the maximum allowable speed for which the tire is designed. The fact is that you can’t drive for a long time (more than half an hour) at this very maximum speed. This is due to excessive tire wear. In addition, it is life-threatening, because at high speeds the rubber should work in normal, not critical modes. Therefore, it is allowed to drive for a long time at speeds 10 ... 15% lower than the maximum allowable. Such reasoning is especially relevant for bad roads, when the rubber constantly gets into pits, potholes and runs into bumps.
Do not exceed the speed limit and do not drive for a long time at the maximum speeds allowed for rubber.
When choosing tires based on the speed index, as in the case of a load, you cannot choose very “fast” tires. The fact is that the faster the tire is designed for, the softer it is. Accordingly, it will have better and more reliable grip on the road surface. However, this is much wears out faster(remember how often tires are changed at Formula 1 races). That is why it is not recommended to buy very high-speed tires for ordinary cars used in urban areas.
Results
We are sure that the above information will help you understand what the load and speed indices of tires mean, whose designations are located behind the tire size value. This will help you make the right choice. At the same time, do not forget to leave a small margin of 10 ... 20% for both indices in order to ensure driving comfort and safety on the road.
The load index (aka the index of carrying capacity or bearing capacity) is the name of the maximum allowable weight, under the pressure of which the tire is able to function normally. This indicator is especially important for owners of trucks, since the weight of their cars is constantly changing and can reach huge values.
Features of tires with high bearing capacity
To increase the load index, tire manufacturers use stronger materials and reinforce the roll. Rubber becomes more stable, but its rigidity inevitably increases. This means that the higher the load index, the less comfortable the ride will be. Hard rubber not only absorbs worse, but also creates a rumble while driving. The only way to make the operation of the car more comfortable is to take tires with a lower load index. In this case, the owner will no longer be able to transport the previous amount of cargo, but the car will move more smoothly, and the pressure on the suspension will decrease.
Index decoding
In order to avoid confusion, global tire manufacturers use a single index table in the manufacture of tires. The smallest load index among the existing ones is 0. It corresponds to an indicator of 45 kilograms. This means that a tire with this index is able to withstand loads up to 45 kilograms. The maximum index is 230 with a corresponding indicator of 33,500 kilograms.
These indicators are optimal, not limiting values. For example, if the load index of a tire corresponds to five hundred kilograms, then this does not mean that with a load of 600 kg the tire will be torn apart. From time to time it is permissible to exceed the recommended load by twenty to thirty percent. But when buying tires, you should focus on the recommended value, which, along with the speed index, is indicated in the technical documents of any car.
Additional markings: ply rating and maximum load
The load index is not the only indicator by which one can judge the bearing capacity of a tire. There is also the concept of ply rating or PR (from the English “ply rating”). The higher this figure, the greater the load the tire can withstand. For example, for passenger cars, the ply rate is in the range from 4 to 6 PR, and tires with a PR value of 6-8 are usually installed on minibuses or small trucks. For large-sized vehicles, like agricultural machinery, tires marked "Reinforced" (literally, "reinforced") or XL are used. This tire has the maximum ply and is able to withstand the heaviest loads. An alternative option is the sign "C", that is, "commercial". It is put on tires for vehicles with a large load capacity.
And yet, the ply rate, as an indicator of the optimal load, is imperfect. Tires of different sizes with the same ply rating are able to withstand completely different loads, so ply rating is not an independent indicator. Today, tire manufacturers use it less and less and indicate the load-bearing capacity on the sidewall.
Sometimes, in addition to the load index, the manufacturer indicates the maximum allowable load in kilograms. To recognize it, you need to find the inscription “max. load" followed by a number.
It is important to consider that the limit load indicator is always indicated per tire. To calculate the coefficient for a car, you need to multiply the value by four.
Relationship between load index and speed index
The bearing capacity coefficient is related to the speed index, which was discussed at the beginning. Let's say the 80R marking means that the recommended speed for the tire is 170 km/h and the maximum load is 450 kilograms. But after all, the load on the tire is directly proportional to the speed: the faster the car moves, the higher the load on the tire. To avoid confusion, on each tire, manufacturers indicate the load factor for the maximum allowable speed. In the example above, a load of up to 450 kilograms would be allowed at a speed of 170 km/h. If you go slower, then you can take more cargo. The reverse is also true: if the pressure on the wheels is reduced, the recommended speed limit can be exceeded. There is a formula: five percent weight reduction allows you to increase the maximum speed by 10 kilometers per hour.
Load capacity and speed factor as elements of the frame size
All technical information about the tire is indicated on its sidewalls. The name of the manufacturer, model, type of cord, country of manufacture and other data are noted there. Among other information, there is always a block of information on the sidewall, which is called the standard size. Let's take size 185/75R14 82S as an example. Here 185 is the width of the tire in millimeters, 75 is the height in millimeters, R is the type of tire (in this case, radial, but can also be diagonal and denoted by the letter D or diagonally belted and denoted by the letter B), 14 is the rim diameter in inches, 82 - load index (475 kilograms), S - speed index (180 km / h).
For large trucks, twin tires are sometimes used. The limit load coefficient for each tire in a pair may vary, and in this case, the load index is indicated for each tire separately, through a fraction.
(in - load index, kg - weight in kilograms)
