Not all car owners can immediately tell which one tire size must be installed on their car model. Moreover, not all car owners know how important the correct selection of tires is for the safe and trouble-free operation of your four-wheeled friend. Let's take a closer look at what can be written on the sidewall of a tire and how exactly tire size affects the safety of your driving.
To determine the type and size of your car's tires, you can use the tire calculator.
The easiest way to determine which tire size must be installed on your car - this is to look into the instruction manual that was given to you along with the car. You can also try to look at the sticker on the pillar between the doors on the driver's side. Several numbers and letters will be written there, something like this - 185/70 R14. What does this "Chinese letter" mean? The first digit in this designation indicates the width of the tire, expressed in millimeters. The second number, located after the fraction, indicates the height of the tire profile, but not in millimeters, but as a percentage of the width. That is, in our case, this means that the tire height is 70% of 185 mm. The higher this figure, the higher the profile of the tire. The letter R - means that the tire has a radial cord (there is also a D marking, which means a diagonal cord, but this type of tire is very rare). And the number after this letter indicates the diameter of the disk for which this tire is intended. So, if someone asked for “wheels of the 14th radius” in front of you, then this person completely misinterpreted the inscription R14. The main inscription may be followed by additional letters and numbers that define top speed for that tyre, the maximum load per wheel, and the season or type of surface for which the tire is recommended. In addition, it can also be indicated for which type of car (for example, for SUVs) this tire is intended.
Now you know which tire size recommended your car manufacturer, but you don't always want to follow these recommendations. Often, a car owner wants to highlight his car from total weight, and he wants to do this by installing tires custom size. However, here you can expect a lot of pitfalls and now we will talk about some of them.
First, if you want to fit larger tires (more accurately, fit larger rims and put tires on them with a higher profile height), then you will need to make sure that the new wheels do not rub against the suspension or bodywork. Moreover, for the front wheels, you need to check the absence of contact with the body or suspension at all steering positions. And for rear wheels you need to make sure that they do not touch the arches when the car is fully loaded. If these requirements are not met, then your brand new tires can become unusable in just a few hundred kilometers, and even seriously let you down somewhere far from home.
Secondly, it is not uncommon for a driver to want to install so-called low-profile tyres, i. tires with a profile height of 55 or even 45 percent of the width. Such tire size gives the car an unusual look, but it is worth remembering that in this case you seriously reduce the ground clearance of your car. Of course, if the roads on which you move have excellent coverage, and your car does not leave the country road, then the clearance will not interest you and you can put tires of any height. However, most often, when buying such tires, the owner forgets about such nuances, but remembers this on the first pit or bump during a trip to the country. Yes, and it is much easier to deform such a tire when it hits a hole, and not everyone can afford to change tires after a couple of unsuccessfully encountered potholes. Pay attention to someone else's low-profile rubber - you can often see swelling on its side (lateral hernia) on it.
Further, when driving in the summer, you can select tire size with greater width. In this case, traction with the road surface is improved. But for winter, it is better to take tires with a smaller width, which will increase the pressure in the contact patch and improve traction on snowy or ice-covered roads. When choosing a tire type, consider the maximum speed of your vehicle and Weight Limit your car with a full load. Also pay attention to the climate in your area and work road services in winter. If you have a lot of snow in winter, then an inexpensive one is unlikely to suit you. all season tires. In addition, pay attention to the condition of your roads in the summer, if you regularly travel on roads with a lot of holes, then you should think about purchasing tires with a higher load index, since such a tire will have a reinforced sidewall, which means it has a significantly better chance survive after meeting with the pit.
In the life of every experienced car owner who has an active driving experience of 3-5 years, there were situations when he needed to pick up rim. However, this procedure is far from always possible to do according to the available parameters and geometric characteristics, because the disk itself may not be at hand. In such cases, car owners are often helped by knowing the dimensions of their tires, since these figures are enough to simply select the product of interest.
Many car enthusiasts who are preparing to buy new wheels to replace worn, damaged ones, or simply in connection with seasonal “changing shoes”, often ask the same question - how to choose wheels for tires according to tire size?
Tire size on the label
To answer this question, it is necessary to know the general parameters by which these two products are inextricably linked, in particular:
- The radiality should be the same for both the rim and the tire, because this parameter always determines the correspondence of rims and tires, as well as their compatibility. So, the most popular wheel sizes are the range from R13 to R20, where the number shows the diameter in inches, but many motorists mistakenly consider this value to be the radius.
- Wheel width corresponding to the same value on the tire, which can only slightly fluctuate. This dimension on the wheel is indicated by the letter J, which is preceded by its value in inches. So, for example, the range 5.0J-6.0J corresponds to a tire width of 175 mm, 5.5J-7.0J - 215 mm, 6.0J-7.5J - 225 mm, and 7.0J-8.5J - 245 mm. Thus, the width of the disks and the width of the tires are absolutely interconnected indicators.
- The next important indicator is the rubber profile, which determines the overall dimension of the wheel assembly. So, for example, for the R17 radiality on the Lada Kalina, you can put tires with a profile height of 40 to 45 mm, because the wheel arches and suspension structures are designed only for such a maximum dimension, but, for example, with the same dimension on Toyota Land Cruiser 200 will easily fit a profile with a height of 100 mm.
- Recently, rubber has been produced only tubeless, because the risk of an accident in the event of a puncture is minimal, and the edges of the tire, as well as the sides of the rim of the disc, have special rigid ribs that completely eliminate the passage of air after rubber and steel come into contact. However, with chamber rubber, it is necessary to look for discs suitable for it, and this is very problematic to do.
- Those vehicles that actively drive off-road often use devices such as beadlocks - powerful bolted steel discs mounted on the inside of the wheel and pressing the rubber. These devices prevent the tire from rolling off the wheel rim even when it can no longer maintain pressure due to an accident.
Beadlock disk Most the best way when purchasing a disc, have the rubber itself available, or at least know all its characteristics and be ready to always find it in a search engine on the Internet so that the seller can correctly select for his client the disc of interest to him with optimal parameters.
Ratio table wheels and tires
In order to make it easy for the driver to decide on the selection of the size of the disks according to the tire parameters he has, the following is a table of the most common geometric characteristics of the wheels:
| Rubber height | Tire size | Optimum rim width in inches | Minimum rim width in inches | Maximum rim width in inches |
| R13 | ||||
| 80 | 155/80/R13 | 4,5 | 4,0 | 5,5 |
| 70 | 165/70/R13 | 5,0 | 4,5 | 6,0 |
| 65 | 175/65/R13 | 5,0 | 5,0 | 6,0 |
| 60 | 185/60/R13 | 5,5 | 5,5 | 6,5 |
| 55 | 195/55/R13 | 6,0 | 5,5 | 7,0 |
| R14 | ||||
| 80 | 175/80/R14 | 5,0 | 4,5 | 5,5 |
| 70 | 185/70/R14 | 5,5 | 5,5 | 6,5 |
| 65 | 185/65/R14 | 5,5 | 5,5 | 6,5 |
| 60 | 195/60/R14 | 6,0 | 5,5 | 7,0 |
| 55 | 205/55/R14 | 6,5 | 5,5 | 7,5 |
| R15 | ||||
| 80 | 185/80/R15 | 5,5 | 5,5 | 6,0 |
| 65 | 195/65/R15 | 6,0 | 6,5 | 7,0 |
| 55 | 205/55/R15 | 6,5 | 6,5 | 7,5 |
| 50 | 205/50/R15 | 6,5 | 6,5 | 7,5 |
| 45 | 195/45/R15 | 6,5 | 6,0 | 7,5 |
| R16 | ||||
| 60 | 225/60/R16 | 6,5 | 6,0 | 8,0 |
| 55 | 235/55/R16 | 7,0 | 6,0 | 8,0 |
| 50 | 205/50/R16 | 6,5 | 5,5 | 7,5 |
| 45 | 205/45/R16 | 7,0 | 6,5 | 7,5 |
| 40 | 225/40/R16 | 8,0 | 7,5 | 9,0 |
| R17 | ||||
| 55 | 225/55/R17 | 7,0 | 6,0 | 8,0 |
| 50 | 215/50/R17 | 7,0 | 6,0 | 7,5 |
| 45 | 235/45/R17 | 8,0 | 7,5 | 9,0 |
| 40 | 255/40/R17 | 9,0 | 8,5 | 10,0 |
| 35 | 265/35/R17 | 9,5 | 9,0 | 10,5 |
| R18 | ||||
| 50 | 235/50/R18 | 7,5 | 6,5 | 8,5 |
| 45 | 255/45/R18 | 8,5 | 8,0 | 9,5 |
| 40 | 265/40/R18 | 9,5 | 9,0 | 10,5 |
| 35 | 295/35/R18 | 10,5 | 10,0 | 11,5 |
| 30 | 325/30/R18 | 12,0 | 11,0 | 13,0 |
| R20 | ||||
| 40 | 245/40/R20 | 9,0 | 8,0 | 9,5 |
| 35 | 275/35/R20 | 10,0 | 9,0 | 11,0 |
Using the data of this table, any motorist will be able to easily choose the ones that interest him wheel disks and make no mistake, which will ensure a comfortable and safe ride.
Autodisk options How to choose the right wheel width
When choosing the width of the wheels, the driver should follow certain rules, because there are some inconsistencies in the international designation of dimensions.
First of all, don't be mistaken about the different units, because the width of the wheel rim is specified in inches, while the tire is indicated in millimeters. So, in order to compare numerical indicators, you need to multiply each inch by 23.5 mm.
Also, the buyer should not be confused by the fact that several sizes of disks can fit on a tire of the same width at once. This is due to the fact that the rubber product is elastic and can be deformed at the interface with the disk by several centimeters.
When choosing a disc, you need to remember that a wheel that is too narrow can cause a tire failure, since during pressure build-up it will expand more and more, and the sides of the steel product may not hold it at some point.
On the contrary, a disc that is too wide can be damaged, since the side profile of the rubber will not protect it from negative external influences, especially when driving off-road or in deep snow.
The summer-only rim can be made wider to make the car look more impressive on the track or in big city, and in winter, on the contrary, narrower, because the powerful side parts of the rubber should protrude as much as possible.
If a car enthusiast chooses stamped wheels and is preparing to protect them with caps, he should be aware that plastic or rubber linings also have a thickness, and so that the wheel does not look like with a negative offset, he should choose its smallest width based on the table values \u200b\u200bgiven above.
Wheel with low profile tires Many large points of sale of such products often have special calculator programs available, combined with an electronic database for accounting for goods in stock. So, a car enthusiast just needs to report the parameters of his tires, which the seller immediately drives into the program as initial data, and a list of optimally suitable products available is displayed on the screen.
How to choose the right wheel size for your tire
Which wheels fit which tires and vice versa? In order for the driver to be sure of the correct choice of the disk of interest to him and not regret the useless purchase later, he must take into account the following features of this product, looking for the right thing for himself:
- The radiality of the tire is determined not by its outer contour, but by the fit size at the location of the hard beads for installation on the disk. So, if it is not possible to determine its size on a worn product, it is enough just to measure the inner diameter and divide the resulting number by 23.5 mm to convert the indicator to inches.
- Rubber with the Ran Flat function, quite often bundled with sports cars or with those European brands, the developers of which paid special attention not to practicality when replacing a flat tire, but to free space in the trunk, it has very rigid sides and internal transverse stiffeners. This means that the rim must be made of heavy-duty metal, preferably forged, because those hard ribs can easily warp the rim when riding for a long time on a damaged tire.
- The same can be said if the outer radius of the tire differs little from the inner one due to a too low profile. So, when driving on a rough road, the outer surface of the rim will always be impacted, because the cushioning effect from the air buffer is minimal.
- When choosing a rim for a minibus, full-size SUV or pickup truck, that is, a vehicle that can be subjected to significant loads, unlike a car, it is important to consider the index maximum weight on the tire. This means that if the wheel can be pumped up to 2.7-3 atm., and it will be operated under a constant load of 1 ton or more, then the disk itself must also be reinforced, otherwise normal use of the wheel assembly simply will not work.
Run flat tire If the inner rim of the wheel has a radial R17 or more, be sure to use only a cast or forged wheel as the main wheel. This is due to the fact that relatively thin stamping sheets are unstable and prone to damage when driving, sharp maneuvers or encountering obstacles during long-term operation of the vehicle. In the case of a spare tire, for 1-2 uses for the entire period of operation of a car, it is unlikely that anything will happen to the product.
The main mistakes motorists make when choosing rims
Not every driver can choose exactly the product that is optimal for his car the first time. Comparing disks by parameters is far from the final procedure, after which you can safely purchase a product. So, at retail outlets, returns often occur, as potential buyers make mistakes.
Regardless of the size and type of rubber, the disk can sit perfectly on it, but not fit on the hub. This means that mounting point information is just as necessary as tire size information, because there are two most important indicators specific to a particular car model. These parameters are drilling, that is, the diameter of the mounting hole in the disk, and bolt pattern is the number of studs and the length of each of them. Without knowing these parameters, the mistake of buying an unnecessary product is very likely, since there are many variations.
People often take a disk of the maximum allowable width and do not monitor the ET - overhang, and also do not resort to comparing disks. So, this characteristic, for example, ET20, 25, 30, 35, 40, means the distance in millimeters from the point of attachment of the product to the hub to the extreme plane of the disk flange.
In order to choose the offset of the disc correctly, the dimensions of the tires are not needed at all, since the dimensions of the wheel arch and how much the hub is deepened beyond the transverse dimensions of the car are important here.
If these parameters are incorrectly determined, motorists are often faced with the fact that the rubber touches the wheel arches when driving, cornering or while driving on a bad road and, accordingly, interferes with the active operation of the shock absorbers. In addition, the wheel may begin to protrude beyond the car, which will inevitably pollute the body in rainy weather without installing additional fender liner around the wheel arch perimeter. There is also a risk of damage to the discs during parallel parking of the car near the curbs.
high profile tires with a small radius disc on an SUV In order to avoid these mistakes, motorists should study all technical specifications not only their rubber, but also the car itself, using the instruction manual or consulting with experts in this field.
Before choosing a car, you need to use a special calculator yourself, since many sites have such a system to help motorists. So, for example, following the link, you can enter the make of the car, its model, modification, year of manufacture, VIN number, tire sizes and other known parameters, and the system will absolutely accurately determine all the ranges of disks that will most likely fit without any modifications or problems on the hubs specific "iron horse".
In addition, immediately on such portals there is information about which brands and at what price they produce and sell these wheels, which will help the buyer to finally decide on the purchase and then not regret it.
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 consider 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). Accurate change data external dimensions wheels you can calculate 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 it performance characteristics 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 passenger cars mobiles 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 normal work 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). 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. On many summer tires for SUVs, M&S is indicated. 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 harsh 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 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).
To simplify the determination of tire size, a special tire calculator, allowing the user to do without the need to decipher the digital 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. Determine the appropriate distance inside between the wheel and suspension, and from the tread to the shock 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 geometric dimensions new tires from previously used ones. 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. However, due to the change standard sizes tires have the ability 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. As the profile decreases, stiffness increases, 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. Correct selection tires, it's not only necessary security, but also optimization road opportunities 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.
It is always better to purchase complete wheels right away, but if you suddenly had to start selecting tires according to disks, then don’t worry, now we will 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 indicated by the symbol "D" and is considered the most significant characteristic. It is very important to follow the dimensions recommended by the manufacturer. The increased diameter will contribute to the distortion of the speedometer readings. It is also possible for the wheel to rub over the 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 in the marking it is usually indicated 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 state pavement not ideal, it is better not to buy such tires, since in this case the load on the suspension increases, and there is a possibility of disk deformation. In addition, they are noisier.
"Wt" - tire width. For driving on a dry track, wide tires are better, as this reduces braking distances. For urban conditions and slippery roads, it is recommended to use narrow tires.
Before talking directly about the selection of tires by disks, it is necessary to disassemble a little in the marking of one and the other. Let's start with disks. The marking may be embossed anywhere except on 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 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 full drive.
If you see the symbol “x” behind the letter designations, then this means that the disc has a one-piece design, but collapsible copies in the marking contain the “-” sign. Next, the diameter of the disks is indicated, followed by the hump index. This is a value indicating the annular protrusions along the rims. They are entrusted with very important function– fixation of tubeless tires during turns. A simple hump is denoted by a single letter "H", flat, as in our case, "FH", and an asymmetric one - "AH". There are designs in which there are no humps.
Next, the value that you need to pay special attention to when choosing 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 following indicates the distance between the plane of attachment of the disk to the hub and its vertical axis. This parameter is called disc overhang and is denoted by a combination of letters "ET". The number following them indicates the offset value in millimeters, in our case it is 20 mm.
The overhang can be positive, zero, or negative. Suspension and steering are adjusted depending on this parameter. The last in the marking indicates the diameter of the mounting hole. For passenger cars, this value is in the range from 50 to 70 mm. Quite often, the maximum load, the date of manufacture and the method of production are also specified. Discs are available forged, cast and stamped.
Tire marking
If you decide to start selecting tires according to the width of the disks, then you definitely need to be able to decipher the rubber markings. After all, this code contains all the necessary information. You can find it on the side surface of the tire. However, it also indicates a lot of other information about rubber, starting from the country of the manufacturer, model and ending with the 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 the selection of rubber for certain disks, then they do not play a decisive role.
But the most important information contained in a code called a type. To make it as clear as possible, consider the decryption using a specific example. Let's say you found 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 value, expressed as a percentage relative to 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 that the tire has a radial ply. And the number following it expresses mounting dimension rim, it is indicated in inches. In fact, this is the most important information that is needed when selecting tires by size. The marking also contains a column with speed indices, as well as loads. There are many tables on the Internet in which these alphanumeric designations are translated into specific values \u200b\u200bof loads and speeds.
What will help you choose the right tires?
The choice of rubber is a very responsible task, because if you put inappropriate tires on a car technical specifications tires, then problems cannot be avoided. These may be incorrect speedometer readings, and even wheel arches touching the rubber. How to find out what tires are needed if, for example, you bought a used car and faced with their replacement for the first time?
There are several ways to do this. The easiest way is to look in the book for the operation of the machine, in it you will surely find the necessary data. Sometimes we don’t have such an opportunity, in this case you can look under the glove box 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?
Do not be discouraged, you can always go to specialized sites that sell tires, and by filling out the plate (year, brand and other information about vehicle), you will receive detailed information on tires that are ideal for your car. If you decide to put tires of a different size on the car, then the 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% over size disc 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 details coincide in their own central holes. But if for some reason this does not work out, then a special adjusting ring will come to the rescue. Its outer diameter corresponds to the disc hole, and its inner diameter corresponds to the hub.
But this is not all the features of selecting tires for. It is also necessary that the tires strictly correspond to the diameter of the circumference of the disc mount centers. A maximum run-out of 2 mm is allowed. In this case, special bolts with eccentrics are used for fixing. But it is best if these parameters match 100%.
In order not to miscalculate exactly with the choice, you can refer to special tables for selecting tires for disks, where their sizes and correspondence are indicated.
There is also such a thing as maximum load. Usually they rarely pay attention to it, since disk manufacturers make their products with a good margin of safety. However, if you decide to experiment and, for example, install wheels 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 hillock will lead to very sad consequences.