Car owners use a tire calculator to select tires and wheels of the appropriate size. All calculations are performed online. The user does not have to deal with lengthy, incomprehensible calculations. The application is multifunctional, since the motorist will be able to understand how to change the dimensions of the wheel, taking into account changes in the sizes of tires and rims. Let's look at the features of using the service.
Tire calculator functionality
The tire selection calculator can help you select tires that are suitable for a specific car in size and characteristics. Vehicle owners resort to the service when it is time to replace tires and wheels on their vehicles. In order not to waste time on meaningless “changes of shoes” and checks, use the offered online service. Tire calculator features:
- you can calculate tire sizes;
- the service provides various parameters - wheel diameters, changes in the height of clearance between the road and the car (clearance), widening of the track;
- assistance in converting inches to millimeters or vice versa, using American and European size charts.
The tire calculator was designed to speed up tire selection, making the procedure much easier. Since every car owner is faced with difficult choices, online calculators very quickly gained popularity among users.
How to use a tire calculator
There are several tips that will help you use the tire size calculator for its intended purpose. Step-by-step instructions consist 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.
- The user will see a special table with the calculation results. From this data you can find out what tires are needed for a particular vehicle.
- After selecting tires, you can proceed to calculating the size of the wheels. Here you will need to specify 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 analogues in American and European sizes. Comparison using a tire calculator will be as accurate as possible, since all the necessary information is included in the online service database.
The general selection procedure is very simple, but the car owner will definitely be required to enter initial data. The parameters must be as accurate as possible so that there are no errors or inaccuracies in 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, you should use the instructions provided.
The matching of the wheel width and the tire width affects the stability of the car. To ensure safe and comfortable driving, it is necessary that the ratio of these parameters be within optimal limits - those recommended by the manufacturer, otherwise the adhesion of the tire to the disk and road surface will deteriorate, and the risk of an accident will increase.
Theoretical part
Assembled wheelThe vehicle's operating instructions indicate the size of tires and wheels. But many car enthusiasts try to install larger rims on their cars, as they believe that such actions will increase the stability of the vehicle. This opinion is not entirely correct. If you slightly increase the rim of the product, you can get the following benefits:
- increasing speed;
- improved handling;
- increasing machine stability.
If the disc is enlarged beyond the permissible norm, negative consequences are possible:
- deterioration of traction - the wheel will touch the car’s fender;
- increasing load on the transmission;
- decreased car controllability.
If you want to install, for example, low-profile tires to make driving easier, keep in mind that such actions can lead to negative consequences:
- increased risk of damage to discs when driving on uneven road surfaces (potholes, ledges, etc.);
- increasing the load on the car’s suspension while driving over potholes and other uneven surfaces.
The ideal option is to select products taking into account the compatibility of tires and wheel sizes. This can be achieved taking into account:
- recommendations of the car dealer - the compliance of the width of the rim and tires is indicated in the car manual;
- data from special tables for selecting wheels and tires by size.
You can select the tire size to match the size of the disc, and vice versa, using special tables, taking into account the width of the disc rim; it should be 25-30% less than the width of the rubber profile. For example, for 175/80R14 tires, the width is 175 mm, the profile height is 80%, and the wheel diameter is 14 inches. Let's calculate the profile width in inches - 175mm = 6.89 inches, if we subtract 30% from this value and round the resulting number to the nearest disc rim value, we get 5 inches. According to calculations, a rim with a rim width of 5 inches is suitable for a tire with a standard size of 175/80R14.
Installing too large (Figure 1) and too small (Figure 2) wheels on a vehicle.
Figure 1: Installing Larger Wheels 
Figure 2. Installing smaller wheels R12 tires
Episode 82
Tires 125R12: recommended rim width 3.5; minimum 3.0; maximum 4.0.
Tires: 135R12 recommended rim width 4.0; minimum 3.5; maximum 4.5.
Tires 145R12: recommended rim width 4.0; minimum 3.5; maximum 5.0.
Tires: 155R12 recommended rim width 4.5; minimum 4.0; maximum 5.0.
Episode 70
Tires R13
Episode 82
Tires 145R13: recommended rim width 4.0; minimum 3.5; maximum 5.0.
Tires 155R13: recommended rim width 4.5; minimum 4.0; maximum 5.5.
Tires 165R13: recommended rim width 4.5; minimum 4.0; maximum 5.5.
Tires 175R13: recommended rim width 5.0; minimum 4.5; maximum 6.0.
Episode 80
Tires 135/80R13: recommended rim width 3.5; minimum 3.5; maximum 4.5.
Tires 145/80R13: recommended rim width 4.0; minimum 3.5; maximum 5.0.
Tires 155/80R13: recommended rim width 4.5; minimum 4.0; maximum 5.5.
Tires 165/80R13: recommended rim width 4.5; minimum 4.0; maximum 5.5.
Episode 70
Tires: 135/70R13 recommended wheel width 4.0; minimum 3.5; maximum 4.5.
Tires: 145/70R13 recommended wheel width 4.5; minimum 4.0; maximum 5.0.
Tires: 155/70R13 recommended wheel width 4.5; minimum 4.0; maximum 5.5.
Tires: 165/70R13 recommended rim width 5.0; minimum 4.5; maximum 6.0.
Tires: 175/70R13 recommended rim width 5.0; minimum 5.0; maximum 6.0.
Tires: 185/70R13 recommended rim width 5.5; minimum 5.0; maximum 6.5.
Tires: 195/70R13 recommended wheel width 6.0; minimum 5.2; maximum 7.0.
Episode 65
Tires 155/65R13: recommended rim width 4.5; minimum 4.0; maximum 5.5.
Tires 165/65R13: recommended rim width 5.0; minimum 4.5; maximum 6.0.
Tires 175/65R13: recommended rim width 5.0; minimum 5.0; maximum 6.0.
Episode 60
Tires 175/60R13: recommended rim width 5.0; minimum 5.0; maximum 6.0.
Tires 185/60R13: recommended rim width 5.5; minimum 5.5; maximum 6.5.
Tires 205/60R13: recommended rim width 6.0; minimum 5.5; maximum 7.0.
Episode 55
Tires R14
Episode 82
Tires 145R14: recommended rim width 4.0; minimum 3.5; maximum 5.0.
Tires 155R14: recommended rim width 4.5; minimum 4.0; maximum 5.0.
Tires 165R14: recommended rim width 4.5; minimum 4.0; maximum 5.5.
Tires 175R14: recommended rim width 5.0; minimum 4.5; maximum 6.0.
Tires 185R14: recommended rim width 5.5; minimum 4.5; maximum 6.0.
Episode 80
Episode 70
Tires 165/70R14: recommended rim width 5.0; minimum 4.5; maximum 6.0.
Tires 175/70R14: recommended rim width 5.0; minimum 5.0; maximum 6.0.
Tires 185/70R14: recommended rim width 5.5; minimum 5.0; maximum 6.5.
Tires 195/70R14: recommended rim width 6.0; minimum 5.5; maximum 7.0.
Tires 205/70R14: recommended rim width 6.0; minimum 5.5; maximum 7.5.
Episode 65
Tires 155/65R14: recommended rim width 4.5; minimum 4.0; maximum 5.5.
Tires 165/65R14: recommended rim width 5.0; minimum 4.5; maximum 6.0.
Tires 175/65R14: recommended rim width 5.0; minimum 5.0; maximum 6.0.
Tires 185/65R14: recommended rim width 5.5; minimum 5.0; maximum 6.5.
Tires 195/65R14: recommended rim width 6.0; minimum 5.5; maximum 7.0.
Episode 60
Tires 165/60R14: recommended rim width 5.0; minimum 4.5; maximum 6.0.
Tires 175/60R14: recommended rim width 5.0; minimum 5.0; maximum 6.0.
Tires 185/60R14: recommended rim width 5.5; minimum 5.0; maximum 6.5.
Tires 195/60R14: recommended rim width 6.0; minimum 5.5; maximum 7.0.
Tires 205/60R14: recommended rim width 6.0; minimum 5.5; maximum 7.5.
Episode 55
Tires R15
Episode 82
Tires 125R15: recommended rim width 3.5; minimum 3.0; maximum 4.0.
Tires 135R15: recommended rim width 4.0; minimum 3.5; maximum 4.5.
Tires 145R15: recommended rim width 4.0; minimum 3.5; maximum 5.0.
Tires 155R15: recommended rim width 4.5; minimum 4.0; maximum 5.0.
Tires 165R15: recommended rim width 4.5; minimum 4.0; maximum 5.5.
Tires 185R15: recommended rim width 5.5; minimum 4.5; maximum 6.0.
Episode 80
Episode 70
Tires 175/70R15: recommended rim width 5.0; minimum 5.0; maximum 6.0.
Tires 195/70R15: recommended rim width 6.0; minimum 5.5; maximum 7.0.
Tires 235/70R15: recommended rim width 7.0; minimum 6.5; maximum 8.5.
Episode 65
Tires 185/65R15: recommended rim width 5.5; minimum 5.0; maximum 6.5.
Tires 195/65R15: recommended rim width 6.0; minimum 5.5; maximum 7.0.
Tires 205/65R15: recommended rim width 6.0; minimum 5.5; maximum 7.5.
Tires 215/65R15: recommended rim width 6.5; minimum 6.0; maximum 7.5.
Tires 225/65R15: recommended rim width 6.5; minimum 6.0; maximum 8.0.
Episode 60
Tires 195/60R15: recommended rim width 6.0; minimum 5.5; maximum 7.0.
Tires 205/60R15: recommended rim width 6.0; minimum 5.5; maximum 7.5.
Tires 215/60R15: recommended rim width 6.5; minimum 6.0; maximum 8.0.
Tires 225/60R15: recommended rim width 6.5; minimum 6.0; maximum 8.0.
Episode 55
Tires 185/55R15: recommended rim width 6.0; minimum 5.0; maximum 6.5.
Tires 195/55R15: recommended rim width 6.0; minimum 5.5; maximum 7.0.
Tires 205/55R15: recommended rim width 6.5; minimum 5.5; maximum 7.5.
Tires 225/55R15: recommended rim width 7.0; minimum 6.0; maximum 8.0.
Episode 50
Tires 195/50R15: recommended rim width 6.0; minimum 5.5; maximum 7.0.
Tires 205/50R15: recommended rim width 6.5; minimum 5.5; maximum 7.5.
Tires 225/50R15: recommended rim width 7.0; minimum 6.0; maximum 8.0.
Episode 45
Tires R16
Episode 65
Episode 60
Episode 55
Tires 205/55R16: recommended rim width 6.5; minimum 5.5; maximum 7.5.
Tires 225/55R16: recommended rim width 7.0; minimum 6.0; maximum 8.0.
Tires 245/55R16: recommended rim width 7.5; minimum 7.0; maximum 8.5.
Episode 50
Tires 205/50R16: recommended rim width 6.5; minimum 5.5; maximum 7.5.
Tires 225/50R16: recommended rim width 7.0; minimum 6.0; maximum 8.0.
Tires 235/50R16: recommended rim width 7.5; minimum 6.5; maximum 8.5.
Tires 255/50R16: recommended rim width 8.0; minimum 7.0; maximum 9.0.
Episode 45
Tires 195/45R16: recommended rim width 6.5; minimum 6.0; maximum 7.5.
Tires 205/45R16: recommended rim width 7.0; minimum 6.5; maximum 7.5.
Tires 225/45R16: recommended rim width 7.5; minimum 7.0; maximum 8.5.
Tires 245/45R16: recommended rim width 8.0; minimum 7.5; maximum 9.0.
Episode 40
Tires R17
Episode 55
Episode 50
Episode 45
Tires 215/45R17: recommended rim width 7.0; minimum 7.0; maximum 8.5.
Tires 225/45R17: recommended rim width 7.5; minimum 7.0; maximum 8.5.
Tires 235/45R17: recommended rim width 8.0; minimum 7.5; maximum 9.0.
Tires 245/45R17: recommended rim width 8.0; minimum 7.5; maximum 9.0.
Tires 255/45R17: recommended rim width 8.5; minimum 8.0; maximum 9.5.
Episode 40
Tires 215/40R17: recommended rim width 7.5; minimum 7.0; maximum 8.5.
Tires 235/40R17: recommended rim width 8.5; minimum 8.0; maximum 9.5.
Tires 245/40R17: recommended rim width 8.5; minimum 8.0; maximum 9.5.
Tires 255/40R17: recommended rim width 9.0; minimum 8.5; maximum 10.0.
Tires 265/40R17: recommended rim width 9.5; minimum 9.0; maximum 10.5.
Tires 275/40R17: recommended rim width 9.5; minimum 9.0; maximum 11.0.
Tires 285/40R17: recommended rim width 10.0; minimum 8.5; maximum 11.0.
Episode 35
Tires 245/35R17: recommended rim width 8.5; minimum 8.0; maximum 9.5.
Tires 265/35R17: recommended rim width 9.5; minimum 9.0; maximum 10.5.
Tires 335/35R17: recommended rim width 11.5; minimum 11.0; maximum 13.0.
Tires R18
Episode 50
Episode 45
Episode 40
Tires 225/40R18: recommended rim width 8.0; minimum 7.5; maximum 9.0.
Tires 235/40R18: recommended rim width 8.0; minimum 7.5; maximum 9.0.
Tires 245/40R18: recommended rim width 8.5; minimum 8.0; maximum 9.5.
Tires 265/40R18: recommended rim width 9.5; minimum 9.0; maximum 10.5.
Episode 35
Episode 30
Tires R19
Episode 50
Episode 45
Episode 40
Tires 225/40R19: recommended rim width 8.0; minimum 7.5; maximum 9.0.
Tires 245/40R19: recommended rim width 8.5; minimum 8.0; maximum 9.5.
Tires 255/40R19: recommended rim width 9.0; minimum 8.5; maximum 10.0.
Tires 275/40R19: recommended rim width 9.5; minimum 9.0; maximum 11.0.
Episode 35
Tires 225/35R19: recommended rim width 8.0; minimum 7.5; maximum 9.0.
Tires 235/35R19: recommended rim width 8.5; minimum 8.0; maximum 9.5.
Tires 245/35R19: recommended rim width 8.5; minimum 8.0; maximum 9.5.
Tires 255/35R19: recommended rim width 9.0; minimum 8.5; maximum 10.0.
Tires 265/35R19: recommended rim width 9.5; minimum 9.0; maximum 10.5.
Tires 275/35R19: recommended rim width 9.5; minimum 9.0; maximum 11.0.
Tires 285/35R19: recommended rim width 10.0; minimum 9.5; maximum 11.0.
Tires 295/35R19: recommended rim width 10.5; minimum 10.0; maximum 11.5.
Episode 30
Tires 265/30R19: recommended rim width 9.5; minimum 9.0; maximum 10.0.
Tires 275/30R19: recommended rim width 9.5; minimum 9.0; maximum 10.0.
Tires 285/30R19: recommended rim width 10.0; minimum 9.5; maximum 10.5.
Tires 295/30R19: recommended rim width 10.5; minimum 10.0; maximum 11.0.
Tires 305/30R19: recommended rim width 11.0; minimum 10.5; maximum 11.5.
Tires 345/30R19: recommended rim width 12.0; minimum 11.5; maximum 12.5.
Episode 25
Tires R20
Episode 40
Episode 35
Tires R21
Episode 35
Episode 30
Tires 255/30R21: recommended rim width 9.0; minimum 9.0; maximum 10.0.
Tires 285/30R21: recommended rim width 10.0; minimum 10.0; maximum 11.0.
Tires 295/30R21: recommended rim width 10.5; minimum 10.0; maximum 11.0.
Episode 25
Tires R22
Episode 30
Episode 25
Wheel with suspension elements Conclusion
For vehicle stability, it is necessary to comply with the width of the rims and the width of the tires specified by the vehicle manufacturer. If you want to increase the size of wheels or tires, to improve the appearance of the car or its characteristics, you should use special tables indicating the relationship between the parameters of tires and tires. At the same time, keep in mind: even if you have correctly chosen the size of the specified products, there is a possibility that the disc will not be able to be installed on the car due to the design features of the car. For example, the disc will rest against suspension parts or a caliper. This situation can arise due to the cast shape of the wheel, so before beading the tire onto the wheel, you should first try it on.
It’s always better to purchase complete wheels right away, but if you suddenly had to start selecting tires based on rims, then don’t worry, now we’ll study all the features of this process so that even an inexperienced person can handle it.
Main parameters and their designation
First you need to familiarize yourself with the main parameters and their designation. The wheel diameter is designated by the symbol “D” and is considered the most significant characteristic. It is very important to follow the dimensions recommended by the manufacturer. An increased diameter will distort the speedometer readings. It is also possible for the wheel to rub elements of the body and chassis.
The diameter of the rims is designated “dd”, but their width (the distance between the inner edges of the rim) is “Wd”, and is usually indicated in the markings in inches. Height also matters; this characteristic has the code “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 disc deformation. In addition, they are noisier.
“Wt” – tire width. Wide tires are better suited for driving on dry roads, as this reduces the braking distance. For urban conditions and slippery roads, it is recommended to use narrow tires.
Before we talk directly about the selection of tires on rims, we should understand a little about the markings of one and the other. Let's start with the disks. The marking can be stamped anywhere except the inner surface facing the rim. To make it easier to understand, let's look at decoding using a specific example.
Let's say you found the following code "6.5JJx13FH6x98ET20d62.1". The first is the width of the disk 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 a combination of them (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 all-wheel drive.
If you see an “x” symbol behind the letter designations, this means that the disk has a one-piece design, but collapsible copies contain a “-” sign in the marking. Next, the diameter of the discs is indicated, followed by the hump index. This is the value indicating the annular projections along the edges. They have a very important function - fixing tubeless tires during turns. A simple hump is designated by one letter “H”, a flat one, as in our case, is “FH”, and an asymmetrical one is “AH”. There are designs that do not have humps.
Next, the value that you need to pay special attention to when selecting tires for wheels is indicated; this is the location of the mounting holes, in our case “6x98”. This means 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 following indicates the distance between the plane of attachment of the disk to the hub and its vertical axis. This parameter is called disc offset and is indicated by the combination of letters “ET”. The number following them indicates the offset value in millimeters, in our case it is 20 mm.
The offset can be positive, zero or negative. The suspension and steering mechanism are adjusted depending on this parameter. The last thing in the marking is the diameter of the mounting hole. For passenger cars this value ranges from 50 to 70 mm. Quite often the maximum load, production date and production method are also specified. Discs are produced forged, cast and stamped.
Tire markings
If you decide to select tires based on the width of the rims, then you definitely need to be able to decipher the tire markings. After all, this code contains all the necessary information. You can find it on the side surface of the tire. However, it indicates a lot of other information about the tires, from the country of manufacture, model and ending with purpose and type. This information, of course, is of great importance, as it affects the quality of the product, but if we are talking about selecting tires for certain wheels, then they do not play a decisive role.
But the most important information is contained in a code called a type size. To make it as clear as possible, let's look at the decoding using a specific example. Let’s say you found the following code “225/50 R14” on the side of the tire. The first number indicates the profile width in millimeters. Moreover, measurements are made taking into account the sidewalls. Next comes the height value, expressed as a percentage relative to the width. For us it is 50%, which means that to arrive at the size in millimeters, you need 225x50%, which turns out to be 112.5 mm.
The following 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 and alphabetic designations are translated into specific values of loads and speeds.
What will help you choose the right tires?
Choosing tires is a very responsible task, because if you put tires on a car that do not meet its technical characteristics, then problems will inevitably arise. This could be incorrect speedometer readings, or even tires touching the wheel arches. How do you find out which tires are needed if, for example, you bought a used car and are faced with replacing them for the first time?
There are several ways to do this. The easiest way is to look in the machine’s operating book; you will probably find the necessary data in it. Sometimes we don’t have such an opportunity, in which case we can look under the glove compartment lid, where there is a special table with the necessary information. True, there are cars where such a table is not provided. What to do?
Don’t be discouraged, you can always go to specialized websites that sell tires, and by filling out the plate (year, make and other information about the vehicle), you will receive detailed information on the tires that are 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 tires and the speedometer reading.
How to get tires and wheels to match?
But there are cases, again, they are more often associated with used cars, when it is necessary to select tires according to the size of the rims, because these two components must 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. So, for example, if the width of the disk is 5.5 inches, then adding 30% to this value, we get 7.15 inches or 185 mm. It is important that these two parts also match in their central holes. But if for some reason this does not work out, then a special installation ring will come to the rescue. Its outer diameter corresponds to the disk hole, and its inner diameter corresponds to the hub.
But this is not all the features of selecting tires according to. It is also necessary that the tires strictly correspond to the diameter of the circle of the centers of the disc mounts. A maximum deviation of 2 mm is allowed. In this case, special bolts with eccentrics are used for fixation. But it’s best if these parameters match 100%.
To make sure you make the right choice, you can refer to special tables for selecting tires for wheels, which indicate their sizes and compliance.
There is also such a thing as maximum load. Usually, they rarely pay attention to it, since disc manufacturers make their products with a good margin of safety. However, if you decide to experiment and, for example, install rims from a sedan on a jeep, then be sure to find out this characteristic. It is quite possible that the disk will not withstand such a load, and the first hole or bump will lead to very sad consequences.
Some things sound boring and are difficult to remember, but you need to know them. Especially for car enthusiasts. Especially those who consider themselves experts and have their own opinion on any subject. The devil is in the details, and this article is about one such detail.
There is no radius on a tire
Many people now won’t even understand what I’m getting at. “Well, radius, so what? I have 195-65R15 wheels, radius 15, it’s all written down, why are you being clever?!” That's what I'm being smart about. R15 has nothing to do with radius. Neither R nor 15.
Nowadays you can find a lot of information on the Internet, but such little things as the marking of car tires are not among the most popular. We’d rather discuss engine power or the number of goodies in the cabin, right? And we’ll leave the choice of wheels to the store manager. Well, or we’ll ask a friend. He definitely knows! He already has his third car!
In fact, it won’t hurt to understand these boring numbers even just for general development. Moreover, this will both help save money and influence the behavior of the car, but more on that later. For now, it’s a pure educational program, so that later we can understand each other well.
So, 195/65R15. Classic case. Let's squat down next to our car. The first number is the width of the running part of the tire, roughly speaking, the tread width. Expressed in millimeters. That is 195 mm. - this is the width of your wheel. Most people have no problems understanding this figure.
Through the fraction 65 is the profile size. Expressed as a percentage of the width. Not in millimeters! The profile is the part of the tire that “sticks out above the rim.” Sidewall. That is, the height of this sidewall will be 195x65% = 125.75 mm. Not 65 mm. And not anything else. Moreover, from this diagram it clearly follows that the height of 65% with a width of 195 will be one, but if the tire is marked (conditionally) 225/65R15, it will be completely different! 225x65%=146.25 mm. Although the numbers 65 are the same!
R is the radial design of the tire, or more precisely, the way the metal cord is laid inside it. Once upon a time, the tire design involved diagonal laying, but that was a long time ago. Nowadays you almost never see “bias” tires, they are all radial, and the letter R will not tell anyone anything new, it will only cause controversy about the notorious radius...
And finally, the number 15. This is the diameter. The diameter of the tire seat, the inner diameter, the part that comes into contact with the disc. Expressed in inches. 1 inch = 2.54 cm. That is, 15x2.54 = 38.1 cm This is also the outer diameter of the disk, if anyone hasn’t guessed...
Which tires can be installed and which cannot?
And then the fun begins. We can play with these numbers if we want to put other tires (rims) on the car. Ideally, the main thing is that the overall diameter does not differ, or differs slightly. Example.
The 195/65R15 wheel has the following overall diameter: 38.1 cm - inside, plus 125.75 mm x2 = 251.5 mm (there is a profile at both the top and bottom). Let's convert to centimeters for simplicity, it turns out 38.1 cm + 25.15 cm = 63.25 cm. That's how it is! This is the total diameter of the wheel.
Now, if you want to install other wheels, the car owner must understand the following: automakers understand this figure the same way as we do. Taking into account the wheel diameter, the suspension, braking system and body are designed. Therefore, for the same car model (for example, for a Volkswagen Polo sedan), three wheel sizes are officially allowed. The simplest version is content with 175/70R14 (total diameter 60.06 cm), 185/60R15 (60.3 cm) and 195/55R15 (59.55 cm).
It turns out that the “14 wheel” is BIGGER, albeit slightly, than the 15 wheel in the case of 195/55. This is related to the question raised above, about putting on more wheels for the winter... You need to carefully calculate everything. Will a larger diameter number mean a larger wheel size overall? Not always.
The markings of tires produced in America are very different from European designations. Therefore, drivers constantly have to convert inches into millimeters or centimeters. Only after making such calculations can you choose the right wheel for your car.
29 inches
The Russian SUV is produced with wheels whose diameter is slightly smaller than that of a regular SUV. The standard size of foreign cars is 29 inches or 235/75R15.
The domestic SUV (Niva) is equipped at the factory with 175/80R15 wheels. With such tires, the car quickly buries itself in the mud and has difficulty moving on our off-road conditions.
To correct this situation, you need to install 29 inch tires. It will increase the ground clearance by 25 mm. If you install 31-inch tires, the ground clearance will increase by 50 mm. To install such wheels, you only need to change the wheel arches. It will be necessary to increase their dimensions.
Inch system
Most jeeps use tires labeled 31x10.5R15.
31 here refers to the inch diameter of the wheel. One inch, as you know, corresponds to two and a half centimeters, and to be very precise, then 2.54 cm. In other words, after translation, D will become equal to 78.7 cm.
This marking is quite in demand because it is convenient, since it shows the size of the wheel with the disk parameters already taken into account.
The wheel diameter 31x10.5R15 is almost equal in size to a tire designated 31x10.5R16. The only difference will be a reduction in the tire profile by 2.5 cm.
10.5 – tire width in inches. But this value is not entirely accurate, since when converted from inches to traditional centimeters, the result is 26.5 cm.
However, when measuring this value with a regular ruler, the value will fluctuate within 23 cm. Only if the tire has a width index of 12.5 can we talk about a width of 26.5 cm.
You should always remember this nuance if you decide to install the maximum tire size in the arch of an SUV.
Metric system
This measurement system is much more difficult to use. Let's take tires marked 265-75-15.
265 mm – tire width. Just like in the inch system, its actual width will be approximately 230-235 mm.
75 – profile height in millimeters. To get the true value, you need to take 75% of 265 mm. It will be 198.75 mm. This number is then multiplied by two. This is because the total diameter of the wheel is equal to the D of the rim plus twice the profile height.
In our case it is 15 inches. As a result, after the calculations, we get a disk D of 381 mm. Total wheel D: 397.5+381= 778 mm or 77.8 centimeters.
R15 - radial tires. Disc diameter is indicated in inches. Always surprising. Why did the inch designation remain in the metric system?
If you look closely at these two systems, a small difference becomes noticeable, about 1.1 centimeters. It does not affect the design and installation of wheels in any way.
Today, on the Internet, a large number of different calculators are offered to correctly calculate tire size. They all work completely free and make finding the right tire size much easier.
You can view the rating of summer tires 2019 on our website
We have compiled a table of the most common sizes, perhaps it will help you quickly find the appropriate wheel size.
| Designations | Inches |
| 235/65R16 | 28,0 |
| 235/75R15 | 28,9 |
| 225/75R16 | 29,3 |
| 245/70R16 | 29,5 |
| 285/60R16 | 29,5 |
| 225/85R15 | 30,1 |
| 245/75R16 | 30,5 |
| 265/65R17 | 30,6 |
| 265/70R16 | 30,6 |
| 305/60R17 | 31,4 |
| 265/70R17 | 31,6 |
| 265/75R16 | 31,6 |
| 235/85R16 | 31,7 |
| 285/70R16 | 31,7 |
| 285/70R17 | 32,7 |
| 285/75R16 | 32,8 |
| 305/70R16 | 32,8 |
| 255/85R16 | 33,1 |
| 305/75R16 | 34,0 |
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