It is always better to purchase complete wheels at once, but if you suddenly had to take up the selection of tires by disks, then do not worry, now we will study all the features of this process so that even an inexperienced one could cope.
Basic parameters and their designation
First you need to familiarize yourself with the main parameters and their designation. The wheel diameter is denoted by the “D” symbol and is considered to be the most significant characteristic. It is very important to adhere to the manufacturer's recommended dimensions. The increased diameter will contribute to the distortion of the speedometer readings. It is also possible for the wheel to overwrite body and chassis elements.
The diameter of the discs is indicated by "dd", but their width (the distance between the inner edges of the rim) is "Wd", and in the marking it is usually indicated in inches. Height also matters, this characteristic has the cipher "dt". Low profile tires wear out faster and are not suitable for all roads. If the condition of the road surface is not ideal, then it is better not to buy such tires, since in this case the load on the suspension increases, and there is a possibility of deformation of the disks. They are also noisier.
"Wt" is the width of the tires. For driving on dry roads, wide tires are better suited, as this will shorten the braking distance. For urban conditions and slippery roads, narrow tires are recommended.
Before talking directly about the selection of tires by disks, you should make out a little in the marking of one and the other. Let's start with the disks. The marking can be embossed anywhere other than the inner surface facing the rim. To make it easier to understand, consider the decryption using a specific example.
Let's say you found the following code "6.5JJx13FH6x98ET20d62.1". The first is the width of the disc and it is indicated in inches, in our case it is 5.5. to convert this value to millimeters, multiply it by 25.4. This is followed by a Latin letter (P, D, B, K, J) or their combination (JJ, JK). This symbol characterizes the shape of the profile contour, the height of the shelves, their angle of inclination and the radius of curvature. "JJ" indicates that the car is full drive.
If you see the "x" symbol behind the letter designations, it means that the disc has an integral design, but collapsible copies in the marking contain the "-" sign. Next, the diameter of the discs is indicated, followed by the index of the humps. It is a value that denotes annular ridges along the flanges. They are entrusted with a very important function - fixing tubeless tires during turns. A simple hump is denoted by one letter "H", flat, as in our case, "FH", and asymmetric - "AH". There are constructions that lack humps.
Further, the value to which you need to pay special attention to when selecting tires for disks is indicated, this is the location of the mounting holes, in our case "6x98". This suggests that there are 6 of them, and the diameter of the circle is 98 mm. The number of holes ranges from 4 to 6, and the circumference can range from 98 to 137.9 mm. The next is the distance between the plane of attachment of the disc to the hub and its vertical axis. This parameter is called disc offset and is indicated by the letter combination "ET". The number following them indicates the value of the offset in millimeters, in our case it is equal to 20 mm.
Departure can be positive, zero or negative. The suspension and steering gear are adjusted according to this parameter. The last in the marking is the diameter of the bore. For passenger cars, this value ranges from 50 to 70 mm. Quite often, the maximum load, the date of manufacture and the method of production are also stipulated. Discs are available forged, cast and stamped.
Tire marking
If you decide to tackle the selection of tires according to the width of the disks, then you definitely need to be able to decipher the rubber markings. After all, it is this code that contains all the necessary information. You can find it on the side surface of the tire. However, it contains a lot of other information about rubber, starting from the country of manufacture, model and ending with the purpose and type. This information, of course, is of great importance, since it affects the quality of the product, but if we are talking about the selection of rubber for certain discs, then they do not play a decisive role.
But the most important information is contained in the code called the type. To make it as clear as possible, consider the decryption using a specific example. Let's say you find the following code "225/50 R14" on the side of the rubber. The first number indicates the width of the profile in millimeters. Moreover, measurements are made taking into account the sidewalls. Next comes the height, expressed as a percentage of the width. With us it is 50%, which means that in order to come to the size in millimeters, you need 225x50%, it turns out 112.5 mm.
The next symbol gives information about the construction of the cord. "R" means the tire has a radial cord. And the number following it expresses the mounting size of the rim, it is indicated in inches. As a matter of fact, this is the most important information that is needed when selecting tires by size. The marking also contains a column with speed and load indices. There are many tables on the Internet in which these numerical-letter designations are translated into specific values of loads and speeds.
What will help you choose the right rubber?
The choice of rubber is a very responsible occupation, because if you put tires that do not meet its technical characteristics on a car, then problems cannot be avoided. It can be incorrect indicators of the speedometer, and even rubbing rubber on the wheel arches. How do you know which tires are needed if, for example, you bought a used car and are faced with a replacement for the first time?
There are several ways to do this. The easiest one is to look in the book on the operation of the machine, in it you will surely find the necessary data. Sometimes we do not have such an opportunity, in this case you can look under the glove compartment lid, where a special table with the necessary information is located. True, there are cars where such a table is not provided. What to do?
Do not be discouraged, you can always go to specialized sites selling tires, and by filling out the plate (year, brand and other information about the vehicle), you will receive detailed information on the rubber that is ideal for your car. If you decide to put tires of a different size on your car, then a tire calculator will help you track the change in the linear dimensions of the rubber and the speedometer reading.
How to match tires and rims?
But there are cases, again, they are more often associated with supported cars, when it is necessary to select tires according to the size of the disks, because these two components should correspond to each other as much as possible. Then simple rules will help. For example, the width of the rubber profile should be 25-30% larger than the size of the rim of the disc... So, for example, if the width of the disc is 5.5 inches, then add 30% to this value, we get 7.15 inches or 185 mm. It is important that these two parts also coincide in their center holes. But if for some reason this does not work, then a special setting ring will come to the rescue. Its outer diameter corresponds to the disc bore, and the inner diameter corresponds to the hub.
But these are not all the features of the selection of tires for. It is also necessary that the tires strictly correspond to the diameter of the circle of the centers of the disc mountings. A maximum take-off run of 2 mm is allowed. In this case, special eccentric bolts are used for fixing. But it is best if these parameters match 100%.
In order not to make a mistake with the choice, you can refer to the special tables for the selection of tires for disks, where their standard sizes and compliance are indicated.
There is also such a thing as maximum load. Usually they rarely pay attention to it, since the manufacturers of discs make their products with a good margin of safety. However, if you decide to experiment and, for example, install disks from a sedan on a jeep, then be sure to find out this characteristic. It is quite possible that the disc will not withstand such a load, and the first hole or bump will lead to very sad consequences.
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. This value is usually referred to simply as “profile”.
Since the tire profile is a relative value, it is important to take into account when selecting tires that if instead of the 195/65 R15 standard size you want to put tires with the 205/65 R15 size, 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). You can calculate the exact data on the change in the outer dimensions of the wheel 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 characteristics are noticeably 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. it is the inner size of the tire or the outer one at the rim.
91 - load index. This is the maximum permissible load per wheel. For 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 vans 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 speed you can ride on 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 the normal operation of the rubber with the constant movement of the car at the specified speed for several hours.
Speed Index Table:
American tire markings:
There are two different markings for American tires. The first one is very similar to the European one, only the letters "P" (Passanger - for a passenger car) or "LT" (Light Truck - light truck) are put in front of the standard size. For example: P 195/60 R 14 or LT 235/75 R15. And another marking of the tire, which is fundamentally different from the European one.
For example: 31x10.5 R15(corresponds to European standard size 265/75 R15)
31
is the outer diameter of the tire in inches.
10.5
is the width of the tire in inches.
R- a tire of radial design (older models of tires were with a bias design).
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 number 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, then this means that with this index, the tire is capable of withstanding 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 must not be used in winter because 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 intended for use in harsh winter conditions. If the sidewall of the tire does not have this mark, then this tire is intended for summer use 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 are tires on which you can continue driving a car at a speed of no more than 80 km / h with a FULL pressure drop in the tire (in the event of a puncture or cut). On these tires, depending on the manufacturer's recommendations, you can drive from 50 to 150 km. Different tire manufacturers use different designations for 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 is a 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; 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 dimension (eg 195/70 R15C) denotes a 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 complies with 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 versus 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 (the minimum tread size 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).
To simplify the determination of the tire size, a special tire calculator has been developed, which allows the user to dispense with the need to decipher the numerical values on the side surfaces of the rubber. With the help of such a calculator, the difference in tire sizes, profile height and other parameters is determined. In addition, such a calculator allows you to receive other related information, for example, on the deviations of the speedometer, changes in ground clearance, and so on.
Purpose of the Visual Bus Calculator
The visual calculator allows every car owner to easily determine the size of the tires and the width of the required rims. With its help, it is possible to determine the diameter of the wheels, the error of the speedometers, an increase in the road track and changes in the clearance under the bottom of the car. Using a tire calculator, it is extremely easy to determine the optimal size suitable for a particular car model. The built-in size conversion system allows you to instantly convert values from inch to meter and vice versa.
It is advisable to use the potential of the calculator in cases where the car owner switches to using tires and wheels that are different from the original size. It allows you to visually determine the main dimensions, and then simulate them for the selected vehicle. In turn, the selection of tires with its help is impossible, since initially it does not provide for division by manufacturer.
Selection and comparison of tires according to the calculator 2.0
If new wheels and tires of a different size are installed based on the data received from the calculator, it is advisable to additionally carry out a number of measurements. It is advisable to determine the distance on the inner side between the wheel and the suspension, as well as from the tread to the shock absorber cup. In addition, you will need to measure the distance between the tread, fender and steering rods.
In turn, when choosing new tires, it is necessary to proceed from the advisability of a slight deviation in the geometric dimensions of the new tires from the previously used ones. The significant size of the dimensions will cause instability in the movement of the car.
Each car is initially created for certain parameters and dimensions. This fully applies to the permissible size of the used disks and rubber. Correspondingly, the selected rubber models must be within the established limits. The use of a tire calculator allows you to simplify the selection process as much as possible, depending on a specific vehicle.
Russians have to regularly face the replacement of rubber, primarily seasonal. The simplest solution in this situation is to use rubber of the same size. While maintaining the dimension of the rubber, the wheel will also retain its original dimensions.
In cases where rubber of a different size is selected, the selection of appropriate disks is required to obtain a wheel with the required dimensions. At the same time, by changing the standard tire sizes, it is possible to control the driving characteristics of the car, giving it additional softness or stiffness. The higher the profile used, the softer the car feels on the road. As the profile decreases, stiffness increases, and narrow tires provide more grip on snow-covered surfaces, so they look more advantageous on winter roads.
At the same time, when selecting the dimensions of tires and wheels, it is required to adhere to the permissible dimensions. For example, tires that are too wide will touch the wheel arches in motion, rubbing them, and wear intensively on their own. It is also worth taking into account the fact that changing the size of the wheels affects the operation of the speedometer, in particular the magnitude of the error.
From the outside, it may seem that the variety of available configurations significantly complicates the calculations, but the bus calculator greatly simplifies the selection process using 3D modeling. The correct selection of tires is not only the necessary safety, but also the optimization of the road capabilities of the car. At the same time, the presence of the metric and inch system of sizes allows you to work with both American and European standard sizes without problems.
Car owners use a tire calculator to find the right tire and wheel size. All calculations are performed online. The user does not have to deal with lengthy, incomprehensible calculations. The application is multifunctional, as the motorist will be able to understand how to change the dimensions of the wheel, taking into account the changes in the size of tires and rims. Let's consider the features of using the service.
Tire calculator functionality
The tire selection calculator will be able to help with the selection of tires suitable for a particular car in terms of size and characteristics. The owners of the transport resort to the services of the service when it is time to replace the tires and disks with the vehicle. In order not to waste time on meaningless "changing shoes", checks, use the proposed online service. Bus calculator features:
- you can calculate the dimensions of tires;
- the service provides different parameters - wheel diameters, changes in the height of the clearance between the road and the car (clearance), track widening;
- help in converting inches to millimeters or vice versa, using American and European size tables.
The tire calculator was designed to speed up the selection of tires, making the procedure many times easier. Since every car owner faced the difficulties of choosing, online calculators quickly gained popularity among users.
How to use a tire calculator
There are some tips to help you use the tire size calculator for its intended purpose. The step-by-step instruction consists of the following steps:
- In the form you will need to enter the size of the tires installed on the car, as well as those that you would like to install.
- A special table with the calculation results will appear in front of the user. From these data it will be possible to find out which tires are needed for a particular transport.
- After selecting tires, you can proceed to calculating the size of the disks. Here you will need to specify the exact data - the maximum / minimum width of the disk installed on the car. The service will perform all calculations automatically.
- If you need to convert inches to millimeters, you can use an online converter. This action will allow you to find analogs with American sizes and with European ones. Comparison through the tire calculator will be as accurate as possible, since all the necessary information has been entered into the database of the online service.
The general selection procedure is very simple, but the owner of the car will definitely need to enter the initial data. The parameters should be as accurate as possible so that there are no errors or inaccuracies in the subsequent results.
You can use this service on our website. The program is freely available, anyone can make calculations in a few minutes. To simplify the process of use, it is worth using the instructions given.
