What rim width and what tires. On the selection of car rims for tires according to their size. The main mistakes motorists make when choosing rims
To simplify determining the size of tires, a special tire calculator has been developed that allows the user to bypass 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 are determined. In addition, such a calculator allows you to receive other related information, for example, on deviations in the operation of the speedometer, changes in the value ground clearance and so on.
Purpose of the visual tire calculator
A visual calculator allows each car owner to easily determine the size of tires and the width of the required disks. With its help, it is possible to determine the diameter of the wheels, the error of speedometers, the increase in the road track and changes in the clearance under the bottom of the car. Using the tire calculator, it is extremely easy to determine optimal size suitable for a specific car model. The built-in size conversion system allows you to instantly transform values from inch to meter and vice versa.
It is advisable to take advantage of the calculator's potential 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 model them for the selected car. 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
In the case of installing new disks and tires of a different size 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 inside 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 tie rods.
In turn, when choosing new tires, it is necessary to proceed from the expediency of a slight deviation in the geometric dimensions of new tires from those previously used. A significant size will cause instability in the movement of the car.
Each car is initially created for certain parameters and dimensions. This fully applies to the allowable size of the discs and rubber used. Accordingly, the selected rubber models must be within the established boundaries. The use of a tire calculator allows you to simplify the selection process as much as possible, depending on a particular vehicle.
The Russians have to regularly deal with the replacement of rubber, primarily seasonal. The easiest solution in this situation is to use rubber of the same size. While maintaining the dimensions of the rubber, the wheel will also retain its original dimensions.
In cases where tires of a different size are selected, the selection of appropriate discs is required to obtain a wheel with the required dimensions. At the same time, by changing the typical tire sizes, it is possible to control the driving characteristics of the car, giving additional softness or rigidity. The higher the profile used, the softer the car feels on the road. Rigidity increases with a decrease in the profile, and narrow tires give more grip on snowy surfaces, so they look more advantageous on winter roads.
At the same time, when choosing the dimensions of tires and wheels, it is required to adhere to the allowable sizes. For example, too wide tires will touch the wheel arches in motion, rubbing them, and wearing out intensively on their own. It is also worth considering 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 greatly complicates the calculations, but the tire calculator greatly simplifies the selection process using 3D modeling. Proper selection of tires is not only a necessary safety, but also an optimization of the road capabilities of the car. At the same time, the presence of a metric and inch size system allows you to work without problems with both American and European standard sizes.
You may need such a calculator if you want to install instead of standard tires or disks of their counterparts, but of a different size. With it, you can visually represent dimensional changes and only then interpret them for a specific car. At the same time, the calculator is not a tool for selecting tires and wheels, since it does not contain a database of manufacturers.When replacing discs and tires, taking into account the geometric data obtained from tire calculator, it will not be superfluous to independently make several measurements. First, the distance from the suspension to the wheel surface with inside, as well as from the shock absorber cup to the tread surface. Secondly, from the wing, as well as steering rods to the tread surface. In this case, the geometric parameters of the new wheel assembly should not greatly exceed the size regular tires and disks. Otherwise, unstable behavior of the vehicle is possible.
A few basic rules to remember when changing tires and rims.
- The tread of summer tires has a standard depth of 0.8-1 cm;
- When installing disks of a larger diameter than regular ones, it is necessary to reduce the amount of overhang - for every inch of height, 3 mm of overhang;
- It is not uncommon for hub bores on rims that are non-original to have a larger diameter. Therefore, when installing them, you need to use special rings for fixing;
- In the event that the hole on the disk is smaller than the hub mounts, it is strictly forbidden to drill them, as well as to grind the hub itself;
- The correct selection of non-original discs using a calculator will save the driving characteristics of the car;
- If you are not sure about the compatibility of tires or wheels with your car, it is better not to install, or contact specialists for help.
1. What needs to be done?
It is necessary to choose the right tire for a disk with the specified parameters or a specific car.
2. What tire parameters should be considered when buying?
When choosing tires, you need to consider the following parameters:
- seasonality;
- protector type;
- type of tire construction - chamber or tubeless;
- type of cord construction;
- mounting (or landing) diameter;
- tire width;
- profile height;
- load index;
- speed index.
As in the case with the choice of disks, we will make a reservation right away: if at this stage you don’t want to understand numbers and indices, you can simply use the tire calculator of any major online store or online service where you can instantly select tires by specifying the model of your car or the characteristics of the drives you have.
However, if you continue to read, then it has already become clear to you that in fact the above list of parameters is quickly reduced to two or three points, since most of them are obvious or subjective characteristics. Let's go in order.
3. Seasonality
Seasonality is an obvious parameter: at the time of choosing tires, you perfectly understand whether winter or summer tires You need. The issue of choosing the so-called "all-weather" tires and its applicability in year-round operation is a topic for a separate discussion, as well as the choice of mud or "universal". Here it is only worth saying that they should be marked with a “snowflake” icon or the letters “M + S” or “M.S”.
4. Protector type
In general, the tread design can be symmetrical or asymmetrical, as well as directional or non-directional. The symmetrical non-directional tread pattern is the simplest basic pattern and is the most common and inexpensive. The directionality of the tread primarily increases its ability to effectively remove water from the contact patch - this is. Well, the asymmetric tread pattern is designed to combine good drainage and exchange rate stability. The issue of choosing a projector pattern also deserves a separate discussion.
5. Type of tire construction - chambered or tubeless
Tires are designed to be used with or without a tube. However, in modern conditions, the issue of choosing a tire design is practically predetermined: almost all modern car tires- tubeless. Such tires are labeled with the inscription " Tubeless" (which means "tubeless") or " TL".
6. Cord construction type
The type of cord construction - the power part of the tire, its "skeleton" - is also a characteristic that does not require much attention when choosing modern tires: almost all of them today are radial. This fact is indicated by the very letter “R" in the tire marking: for example, the mark " 185/70 R 14 88H" means that this is a radial tire with a 14-inch bore diameter, and not a "radius" of 14 inches, as they often mistakenly say and believe .
7. Mounting (or landing) diameter
This is also an easy parameter if you already have rims for which you are choosing tires: the tire diameter must match the rim diameter. If you choose wheels with tires, you need to check in the owner's manual what diameter wheels are acceptable for use on your model, and only then match them with tires of the same size.
8. Tire width
Tire width is the first numerical index reflected in the tire marking. It is indicated in millimeters: the 185/70 R 14 tire has a width of 185 millimeters. This is perhaps the first parameter from our list, which may vary when choosing a tire for a particular wheel or car.
The point here is that the disk can also have different widths, and the tire must sit correctly on the disk. A tire that is too narrow will sit like a “house” on the disk, which is unacceptable due to the high risk of spontaneous disassembly, and a tire that is too wide will “mushroom”, which is also unacceptable. Some areas of tuning like stance consider landing a “house” beautiful and take it out into a separate one, however, from the point of view of civilian operation, it is not justified and wrong.
Each car model has several options for wheel diameter and rubber dimensions suitable for operation. All these options recommended by the manufacturer are listed in the car's instruction manual: it is worth choosing from these data. In turn, a disk of a certain width has several valid tire options. Here the choice should be made depending on the desired characteristics.
First, wider tires usually provide a larger footprint and therefore better traction. Secondly, under the condition of the same diameter, tires of greater width have a smaller profile - we will talk about it a little lower. Thirdly, wider tires have a greater mass, which will slightly affect the dynamics of the car and fuel consumption. And fourthly, with the increase in the width of the tires, their tendency increases. In addition, tires of different widths have different final costs - as a rule, you will have to pay a few extra hundreds of rubles for additional millimeters. Thus, the width of the tires must be selected taking into account the range allowed by the manufacturer and the desired characteristics.
9. Profile height
The profile height, or series, is the second index reflected in the tire marking. It is indicated as a percentage of the tire width: that is, it is the ratio of the profile height to the width in percent. For example, a 185/70 R 14 88H tire has a profile height of 70% of its width. Calculating the height in millimeters is easy: you need to multiply the width by the profile and divide by 100 - for our tires this figure is 129.5 millimeters.
The height of the profile affects the characteristics of the tire. First, the higher profile provides better comfort and puncture resistance. Lower profile tires are therefore better at conveying the road profile to the suspension and bodywork, and are also more prone to damage when hitting imperfections in the roadway. Secondly, a lower profile provides better handling, and a higher profile, on the contrary, provides a greater “rolling” of the car. Thirdly, as mentioned above, given the same diameter, tires of greater width have a smaller profile - this must be taken into account when choosing in accordance with the desired characteristics.
Load index - a parameter that reflects the maximum allowable load on the tire during its operation. It is indicated by a digital index, indicated after the geometric parameters of the tire: for example, our conditional tire 185/70 R 14 88H has a load index of 88. You can see the decoding of the index in the table given by the tire manufacturer - in our case, the index 88 means an allowable load of 560 kilograms. When choosing tires, it should be borne in mind that the maximum permitted weight of the car, respectively, should not exceed the maximum load indicator multiplied by 4 - according to the number of tires on the car.
Speed Index - a parameter that reflects the maximum allowable speed at which the tire retains its performance characteristics. This is an alphabetic index, the decoding of which also needs to be specified in the table provided by the manufacturer. Tires of the same diameter can have a different speed index depending on other parameters - width, profile, composition rubber compound and, accordingly, prices. If the parameter of the maximum allowable operating speed is important to you, then you need to choose tires of a high price category with the best consumer qualities.
Do you want to choose a tire for your car, but do not understand tire markings well? It's not a problem! In this section, we will help you figure out what tire parameters are, what they mean, and which tire is right for your car.
Find tires / tire catalogDeciphering tire markings.
195/65 R15 91 T XL
195 is the tire width in mm.
65 - Proportionality, i.e. profile height to width ratio. In our case, it is equal to 65%. Simply put, with the same width, the larger this indicator, 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 choosing rubber that if you want to put tires with a size of 205/65 R15 instead of the size 195/65 R15, then not only the width of the tire will increase, but also the height! Which in most cases is unacceptable! (except when both of these sizes are indicated in the car's operating book). You can calculate the exact data on changing the outer dimensions of the wheel in a special tire calculator.
If this ratio is not indicated (for example, 185/R14С), then it is equal to 80-82% and the tire is called full profile. Reinforced tires with this marking are usually used on minibuses and light trucks, where a large maximum wheel load is very important.
R- means a tire with a radial cord (in fact, almost all tires are made this way now).
Many mistakenly believe 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 (indicated by the letter D), but recently it has practically not been produced, since its performance is noticeably worse.
15 - diameter of the wheel (disk) 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 disk, i.e. is the inside size of the tire or the outside of the rim.
91 - load index. This is the level of maximum permissible load on one wheel. For cars it is usually done with a margin and is not a decisive factor when choosing tires (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 faster you can drive on this tire (in our case, IS - H - 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 rubber when the car is constantly moving 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” are placed in front of the 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 example: 31x10.5 R15(corresponds to European size 265/75 R15)
31
is the outside diameter of the tire in inches.
10.5
- tire width in inches.
R- a tire of a radial design (older models of tires were with a diagonal design).
15
is the inner diameter of the tire in inches.
Generally speaking, except for inches that are unusual for us, the American tire marking is logical and more understandable, unlike the European one, where the height of the tire profile is not constant and depends on the width of the tire. And here everything is simple with 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- Reinforced tire, the load index of which is 3 units higher than that of conventional tires of the same size. In other words, if a given tire has a load index of 91 marked XL or Extra Load, then this 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 tires for SUVs are labeled M&S. However, these tires must not be used in winter, as Winter tires have a completely different rubber compound and tread pattern, and the M&S badge indicates good tire flotation.
All Season or AS all season tires. Aw (Any Weather) - Any weather.
Pictogram * (snowflake)- rubber is designed for use in severe winter conditions. If this marking is not on the sidewall of the tire, then this tire is intended for use only in summer conditions.
Aquatred, Aquacontact, Rain, Water, Aqua or pictogram (umbrella)- special rain tires.
outside and inside; asymmetric tires, i.e. It is important not to confuse which side is the outside and which is the inside. When installing, the Outside inscription must 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 (due to 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 arrow this marking on the sidewall of the tire indicates a directional tire. When installing the tire, you must strictly observe the direction of rotation of the wheel, indicated by the arrow.
Tubeless - tubeless tire. In the absence of this inscription, the tire can only be used with a camera. Tube Type - indicates that this tire must be used only with a tube.
Max Pressure; maximum allowable tire pressure. Max Load - the maximum allowable load on each wheel of the car, in kg.
Reinforced or the letters RF in the size (for example 195/70 R15RF) means that this is a reinforced tire (6 layers). The letter C at the end of the size (for example 195/70 R15C) indicates a truck tire (8 layers).
Radial - this marking on the rubber in the standard size means that this is a radial tire design. Steel means that there is a metal cord in the tire structure.
Letter E(in a circle) - the tire meets the European requirements of ECE (Economic Commission for Europe). DOT (Department of Transportation - US Department of Transportation) is an 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 roadway.
Treadwear; relative expected mileage compared to a specific US standard test.
TWI (Tread Wear Indication)- Tire tread wear indicators. The marking on the TWI wheel can also be with an arrow. Pointers are located evenly in eight or six places around the entire circumference of the tire and show the minimum allowable tread depth. The wear indicator is made in the form of a protrusion with a height of 1.6 mm (the minimum tread value for light vehicles) and is located in the tread recess (usually in the drainage grooves).
DOT- Encoded manufacturer's address, tire size code, certificate, issue date (week/year).
With the help of a tire calculator, you can easily calculate how the outer dimensions of the wheel, ride height (clearance), speedometer readings and other characteristics will change when you install tires with a different size on your car. The calculator calculates all tire sizes in millimeters, and the vehicle speed in km / h.
Also, the calculator will help you calculate the required rim width for a specific tire size.
How to use the tire calculator:
First enter the standard size installed on your car, and then the one you want to install and click "calculate". The table on the right will show the results of the calculator's calculations.
Detailed information about tire marking in the section: tire marking.
We recommend that you install only the factory tire sizes that are listed in the owner's manual for your machine. Installation of non-standard sizes may void your dealer's warranty and may affect vehicle performance and handling.
Tire calculator for European tires
Old size:
145 155 165 175 185 195 205 215 225 235 245 255 265 275 285 295 305 315 325
/ 25 30 35 40 45 50 55 60 65 70 75 80 85
12 13 14 15 16 17 18 19 20 21 22 23 24
Found in catalogue:
175/70R13-
175/70R13-
When recalculating tire sizes on a calculator, it should be borne in mind that:
With an increase in diameter rim, (and, as a result, a decrease in the height of the tire profile so that the outer diameter of the wheel remains unchanged) the load on the car suspension increases, and comfort also worsens (the car will become noticeably stiffer).
With an excessive increase in the tire profile, the car becomes a “roll”, it is worse controlled, and at critical values \u200b\u200bof the profile height, the tire may begin to cling to body parts and suspension of the car, which will subsequently lead to its destruction.
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