How to calculate tire sizes. Tire markings
When selecting new wheels for a car, the question often arises: should I get larger or smaller wheels, or for the purpose of improvement? appearance cars or cheaper purchases of tires and wheels. But the most main question, whether the wheels are suitable for my car and how its characteristics will change. You can find out whether the wheels will fit on the gas tank cap or the side pillar of the car (photo 1). Or find your car in our directory of wheel applicability for cars and see the tires recommended by the factory. But it often happens that you can supply other tires that are not officially approved by the factory.
In this case, the main thing is to understand how the speedometer indicators will change, i.e. the speed of the car, since the outer radius of the wheel will change. The ground clearance (ground clearance) will also change. It is not recommended to go beyond the factory tire values by more than 2-3%. The vehicle's handling and behavior, gas mileage, and actual vehicle speed may change.
Tire calculator - size comparison
Our tire calculator will show you visual differences in tire diameter, profile, radius, ground clearance and tire width. The dotted lines indicate the difference in size. At the top you can see visual representation old tire(original size), and the new tire is visualized at the bottom. Just as you noticed, the tire can be seen in the side and frontal projections. You can copy the page address and show it to other people and they will see the same comparison as you see.
But how to understand all these values and the difference in %? This is why we created a tire calculator; it will help you understand the change in all required characteristics and will show the % difference between the old and new tire and even visually display what the old and new size wheel will look like. You just need to enter the tire width, profile and wheel radius. Usually they are displayed in this form - 195\65 R15 (photo 2).
How to use the online tire calculator?
Our online tire calculator is very easy to use. In the upper left corner of the site, there are fields for selecting the tire size. In the top row you need to indicate the size of your original factory tire (or the tires currently installed on your car). These values are written on the tire profile (sidewall). In the first list you need to select the tire width - it is indicated in millimeters. The second list is the percentage of the profile height to the tire width. The third list is the diameter of the disk in inches (commonly called radius).
In the bottom row you need to indicate the size of the new tires. Tires that you are going to install on your car or have already purchased. After that, click "Calculate". Our tire calculator will calculate the differences between the old and new tire and display them in a table and picture. Namely: diameter, width, circumference, tire profile height, number of revolutions per kilometer and change in vehicle clearance. The first columns of the table will show the parameters for old and new tires, the following columns will show the difference in mm and the percentage difference between them.
At the bottom of the tire calculator there is a speedometer to visually compare the speed of the old and new tire. Under the speedometer, you can increase and decrease the speed and see the changes in the speed difference between the old and new tire.
Be careful!
Be careful on the road and follow the manufacturer's recommendations. The reverse side of the installation is not standard sizes tires, there is a risk of losing insurance in the event of an accident, failure to pass a state technical inspection of the car, since the installation of tires not approved by the factory is considered a change in the design of the vehicle.
A tire calculator will help you visually compare the sizes of tires and wheels of a car when replacing them with models with characteristics different from the factory ones. In addition, our online calculator tire not only performs a visual comparison of wheel sizes, but also describes possible changes in the behavior of the car after replacing them.
We would like to note that when changing wheel sizes, you should not completely rely only on the calculation results of a tire calculator. The fact is that in addition to geometric parameters, each car has its own individual design features. Therefore, first of all, preference should be given to the sizes of wheels and tires recommended by the car manufacturer.
However, our visual tire calculator allows you to quite accurately calculate and compare the following wheel and vehicle parameters:
- Wheel outer diameter “D”;
- Rim diameter (disc size) “R”;
- Tire profile height “H”;
- Tire width “L”;
- Changing the vehicle's ground clearance;
- Deviations in speedometer and odometer readings.
Below we will show with an example how to use our tire calculator and how it can be useful.
How to use a tire calculator
To compare the sizes of tires and wheels, you first need to enter into the fields of the calculator the data of the wheels installed on the car on the factory assembly line, since the settings and calibration of the instruments (the same speedometer and odometer) were carried out specifically for this standard size. After that, select the values for new wheels in the calculator: the width and height of the tire profile, as well as the radius of the rims.
The tire calculator will automatically calculate the wheel dimensions and compare them with each other. In addition to comparing tire and wheel sizes, below the calculator you will also see quality characteristics(pros and cons) affecting the behavior of the car in motion. An example in the figure below.
How noticeable certain changes in the behavior of the car will be, and how you will feel them when operating the car, depends on the difference in the sizes of old and new tires and wheels. In any case, you should approach changing wheels wisely. Tire and wheel sizes for cars of the VAZ 2109 - VAZ 2110 family are available.
Using a tire calculator, you can easily calculate how the external dimensions of the wheel, ride height (clearance), speedometer readings and other characteristics will change when installing tires of a different size on your car. The calculator calculates all tire sizes in millimeters, and vehicle speed in km/h.
The calculator will also help you calculate the required rim width for a certain 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 markings in the section: tire markings.
We recommend that you install only the factory tire sizes that are listed in the owner's manual for your vehicle. Installing non-standard sizes may void the dealer's warranty, as well as degrade 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 the directory:
175/70 R13 -
175/70 R13 -
When converting tire sizes using a calculator, keep in mind that:
With increasing diameter wheel rim, (and, as a consequence, reducing the height of the tire profile so that external diameter wheels remained unchanged), the load on the car's suspension increases, and comfort also worsens (the car will become noticeably stiffer).
If the tire profile increases excessively, the car becomes “rolly”, handles worse, and at critical values of the profile height, the tire may begin to cling to parts of the car body and suspension, which will subsequently lead to its destruction.
You may need such a calculator if you want to install instead standard tires or similar disks, but of a different size. With its help, 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 wheels and tires, taking into account geometric data obtained from tire calculator, it wouldn’t hurt to take a few measurements yourself. Firstly, the distance from the suspension to the wheel surface is 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. Wherein geometric parameters The new wheel assembly should not greatly exceed the size of the standard tires and wheels. Otherwise, the vehicle may behave unstable.
A few basic rules to remember when replacing tires and wheels.
- The tread of summer tires typically has a depth of 0.8-1 cm;
- When installing disks with a larger diameter than standard ones, it is necessary to reduce the amount of offset - for every inch of height, 3 mm of offset;
- Often the hub holes on discs that are not original have a larger diameter. Therefore, when installing them, you need to use special rings for fixation;
- In the case when the hole on the disk is smaller than the hub mounts, it is strictly forbidden to drill them out, as well as grind the hub itself;
- Correct selection non-original wheels using a calculator will allow you to maintain 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 seek help from specialists.
In order to choose the right tires for the wheels, you need to know certain parameters, failure to comply with which will seriously worsen the car’s performance on the road. Since the tire fits on the rim of the disk, the width of the profile must be commensurate with it. Let us immediately note that, despite the widespread last years tuning, automakers categorically do not recommend this. After all, if the sizes of the wheels and tires vary greatly, the contact patch will not be even, which means that control may get out of control.
In general, the issue of matching tires and wheels can be considered from two sides. The first is the selection of tires and wheels based on the manufacturer’s recommendations, and the second is this fitment. Fitment is the study of the fit of the tire on the rim and the position of the wheels relative to the wheel arches, which includes negative camber, low seating and other delights that we will not talk about, since we consider it more important to tell how to choose the right one from the point of view of safety and comfort. tires to rims.
To choose the right tires for the wheels, you need to know the markings of the wheels.
Ideally, that is, to be sure of safety, the PCD of the disk (the diameter of the circle of the centers of the mounting holes) cannot be changed. In extreme cases, the sizes of the wheels and tires may differ slightly from each other, but then bolts with eccentrics are used for fastening, which allow you to install wheels with PCD 100 mm on cars with PCD 98 mm. However, it is worth noting that the maximum difference in displacement should not exceed 2 mm, and ideally, the matching of tires and wheels should be one hundred percent.
The sizes of the wheels and tires must also match in their central hole, but if for certain reasons this is not possible, a mounting ring (also known as a spacer ring) will come to the rescue. The installation ring has an outer diameter equal to diameter holes in the disk, and inner diameter corresponds to the diameter of the car hub. If the installation ring is installed correctly, then the driving characteristics will not change. It is worth noting that stamped discs do not have mounting rings. They are installed only on .
The disk markings do not indicate the maximum load ( MAX LOAD), you can find out this parameter either in the passport that some manufacturers of domestic wheels attach to their products, or you can look for this information on the website of the wheel manufacturer. This information is not very important, since manufacturers usually make discs with a safety margin. But, if for some reason you decide to put, say, wheels on a jeep for passenger car, then the maximum disk load will be important parameter. And if you do not take it into account, the wheel may not withstand the load and become deformed, even falling into a small hole.
In addition, even if the sizes of tires and wheels match in all respects, there is still a risk that the wheel will not fit on the car. The reason for this is the so-called X-factor, when the disc rests on the suspension parts or caliper, which is due to the form of stamping or casting. Therefore, we recommend that you first try it on before beading a tire onto a wheel.
Correspondence table for tire and wheel widths
|
Tire height |
Tire size |
Rim width (inches) |
||
|
R12 |
||||
|
82 |
125R12 |
3,5 |
3.0 |
4.0 |
|
70 |
145/70R12 |
4,5 |
4.0 |
5.0 |
|
R13 |
||||
|
82 |
145R13 |
4.0 |
3,5 |
5.0 |
|
80 |
135/80R13 |
3,5 |
3,5 |
4,5 |
|
70 |
135/70R13 |
4.0 |
3,5 |
4,5 |
|
65 |
155/65R13 |
4,5 |
4,0 |
5,5 |
|
60 |
175/60R13 |
5.0 |
5.0 |
6.0 |
|
55 |
195/55R13 |
6,0 |
5,5 |
7,0 |
|
R14 |
||||
|
82 |
145R14 |
4,0 |
3,5 |
5,0 |
|
80 |
175/80R14 |
5,0 |
4,5 |
5,5 |
|
70 |
165/70R14 |
5,0 |
4,5 |
6,0 |
|
65 |
155/65R14 |
4,5 |
4,0 |
5,5 |
|
60 |
165/60R14 |
5,0 |
4,5 |
6,0 |
|
55 |
185/55R14 |
6,0 |
5,0 |
6,5 |
|
R15 |
||||
|
82 |
125R15 |
3,5 |
3,0 |
4,0 |
|
80 |
185/80R15 |
5,5 |
4,5 |
6,0 |
|
70 |
175/70R15 |
5,0 |
5,0 |
6,0 |
|
65 |
185/65R15 |
5,5 |
5.0 |
6,5 |
|
60 |
195/60R15 |
6,0 |
5,5 |
7,0 |
|
55 |
185/55R15 |
6,0 |
5,0 |
6,5 |
|
50 |
195/50R15 |
6,0 |
5,5 |
7,0 |
|
45 |
195/45R15 |
6,5 |
6,0 |
7,5 |
|
R16 |
||||
|
65 |
215/65R16 |
6,5 |
5,5 |
7,5 |
|
60 |
225/60R16 |
6,5 |
6,0 |
8,0 |
|
55 |
205/55R16 |
6,5 |
5,5 |
7,5 |
|
50 |
205/50R16 |
6,5 |
5,5 |
7,5 |
|
45 |
195/45R16 |
6,5 |
6,0 |
7,5 |
|
40 |
215/40R16 |
7,5 |
7,0 |
8,5 |
|
R17 |
||||
|
55 |
225/55R17 |
7,0 |
6,0 |
8,0 |
|
50 |
205/50R17 |
6,5 | ||