This is one of the simplest types of tuning. Why is this needed? There are many options. The most common reason is not liking the look. Let's say you want the wheels to look spectacular. To do this, the disk must be larger in diameter. Well, or you bought a used car, and the design of the rims categorically does not suit you. Perhaps you liked some specific wheels, but their dimension is not included in the list recommended by the car manufacturer. You can also change the wheels for reasons of practicality. But how can the installation of such wheels turn out in the future? Let's figure it out.
First, let's recall the key parameters of the wheel.
- 185 - tire profile width in mm
- 65 - percentage of tire profile height to width
- R - designation of a tire of a radial design
- 15 - bore diameter in inches
So, there are several ways to move away from the size of a regular wheel.
1. Wider tire
While maintaining the standard size, we increase the width of the tire profile while maintaining the percentage of height to width. In our example, we get 195/65 R15. It is important to know here that all cars are designed for the installation of snow chains with a size of at least 12 mm. Indeed, in some European countries, driving on mountain roads without chains is prohibited, and not a single self-respecting manufacturer will make a car so that it cannot be operated in the mountains of France or Switzerland. Therefore, an increase in the width of the tire profile is permissible in most cases by up to 24 mm. At the same time, the car will become a little softer on the move, and wider tires will improve braking performance.
2. Higher tire profile
We leave it the same, and increase the percentage of the tire profile height to width to 70. In our example, we get 185/70 R15. The outer diameter of the wheel increases by 20 mm, which is quite acceptable (remember the reserve for installing chains). Everything would be fine, but in our particular example, the factor intervenes that tires of this size are produced mainly for commercial vehicles and they are too rigid and expensive to install on a passenger car. However, in other dimensions, the situation may be different.
3. Change the diameter of the disc
The story of a friend's car is very indicative. He bought a Kia Rio with a 1.6 engine and a 6-speed automatic. The regular wheels of the car had a size of 185/65 R15. The owner drove through the summer season and was not happy with the car's stiff suspension and insufficient ground clearance. Then he decided to change the behavior of the car, not by tuning the springs with shock absorbers, but by working with the wheels. In preparation for the next summer season, he used forged wheels with a diameter of 14 inches, completely matching the mounting dimensions.
There is noticeably more air between the disc and the tire. The outer diameter of the wheel has also grown (by 9 mm). As a result, the smoothness of the ride has become fantastic. When overcoming the bumps in the road, the car, which was not initially famous for its energy-intensive suspension, began to resemble cars of the log-shaped family, which are super-comfortable on Russian roads. Soft, quiet, smooth. All the problems of dead Russian roads and hard Korean suspension have disappeared. He does not plan to drive, so he does not care about the possible deterioration in road holding at very high speeds.However, a decrease in the diameter of the disc is a very rare occurrence. Much more often it happens that the owner chooses wheels one or even two sizes larger. And "wraps" them in low-profile tires. At the same time, the overall dimensions of the wheel remain almost unchanged or grow within acceptable limits.
It looks impressive, but the smoothness of the ride suffers first of all. Yes, and there are much more chances to damage the wheel on a bad road, because the lower the height of the tire profile, the less the ability of such a tire to withstand shock loads. In everything you need to know the measure. Returning to our example, Rio and Solaris cars in expensive trim levels sport 16-inch wheels with 195/55 R16 tires. In this case, you can play a little with the dimensions. For example, a 195/60 R16 tire will fit in the wheel arch without any problems, since its outer diameter will increase by only 19 mm. The clearance will grow by a decent 9.5 mm, but you can forget about the softness of the ride provided by the 15-inch wheels of the basic modification.4. Increase the width of the disk and change the offset
A separate story when the owner of the car decides to install wider disks. Some people like it when the wheel protrudes a little beyond the arch. Please note that changing the dimensions of the wheel and tire can significantly increase the weight of the wheel assembly. Such weighting will negatively affect the life of the suspension elements and even the body, since large unsprung masses can cause resonant vibrations that the suspension is not designed for structurally. It is also important to remember such a parameter as wheel offset.
Those who like to change the offset of the rims, as a rule, tend to place the wheels wider. The aesthetic component of such changes is controversial, but the resource of the suspension elements will certainly decrease.
Consequences of increasing the overall dimensions of the wheel:
| pros | Minuses |
| Ground clearance increase. On our roads, every millimeter of ground clearance counts. If the bottom of the car is 5–10 mm further from the potholes, then there is less chance of damaging it on a bad road. | The wheel can touch body parts. If the width and diameter of the wheel grow no more than 24 mm from the maximum wheel size recommended by the manufacturer, then this problem is not terrible for you. You can't put chains on after that. |
| Economy improvement. Economy improves slightly on country roads, especially on vehicles with gearboxes that have few gears (4 or 5). | Increase in car roll. Yes, the roll will increase slightly, due to the fact that the center of mass is now slightly higher. In practice, this means a slightly lower limiting rearrangement speed. |
| Changing the speedometer and odometer readings. Regular devices always overestimate the readings. You can check with GPS. And with new, slightly larger wheels, the readings will come in line with reality. Plus or minus you decide. Still, such a discrepancy is made primarily for security reasons. We are for accurate instrument readings. | Decrease in dynamic characteristics. The new wheels are a little harder for the engine to turn, and they themselves are a little heavier. |
| Reducing wheel offset (when the wheels protrude more out of the wheel arches) provides a wider track, which increases the lateral stability of the machine. | Wide disc is easily damaged when touching a curbstone. In addition, if the width of the disk is much larger than the nominal one, the tire carcass does not work correctly. It leads to increased tire wear. |
| In most cases appearance becomes more aesthetic and catchy. | Strongly protruding from the arches of the wheel overload wheel bearings and make driving difficult. It is worth getting the front wheel on the roughness of the road, as the steering wheel literally pulls out of your hands. |
For calculations, it is convenient to use a tire calculator.
Legal aspect
By law, non-standard wheels are prohibited. Therefore, any experiments with the dimensions of tires or wheels are illegal. An exception is if the new dimension is allowed to be installed by the manufacturer. However, in reality, not everything is so scary: if the rims on your small car are not welded to a width of 12 inches, if the diameter is not 19 or more inches, then such wheels will not arouse the interest of traffic police officers. But with obtaining a diagnostic card, problems will already arise.
But what if you put bigger wheels? - examination of the RFCar owners use a tire calculator to select tires and rims of the right size. All calculations are done 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 size of tires and wheels. Consider the features of using the service.
Tire calculator functionality
To help with the selection of tires suitable for a particular car in terms of size and characteristics, the tire selection calculator can. Vehicle owners resort to the services of the service when it is time to replace the tires and wheels on the vehicle. In order not to waste time on meaningless "changing shoes", checks, use the proposed online service. Tire calculator features:
- you can calculate the size of tires;
- the service provides different parameters - wheel diameters, changes in the height of the clearance between the road and the car (clearance), track expansion;
- help in converting inches to millimeters or vice versa, using the American and European size charts.
The tire calculator has been designed to speed up the selection of tires, making the procedure much easier. Since every owner of a car faced the difficulties of choosing, online calculators very quickly gained popularity among users.
How to use the tire calculator
There are several tips to help you use the tire size calculator for its intended purpose. The step-by-step instruction consists of the following steps:
- In the form you will need to enter the size of the tires installed on the car, as well as those that you would like to install.
- The user will see a special table with the results of calculations. From this data, it will be possible to find out which tires are needed for a particular vehicle.
- After selecting tires, you can proceed to the calculation of the size of the disks. Here you will need to set the exact data - the maximum / minimum width of the disk installed on the car. All calculations will be performed automatically.
- If you need to convert inches to millimeters, you can use the online converter. This action will allow you to find analogues with American sizes and with European ones. Comparison through the tire calculator will be as accurate as possible, since all the necessary information has been entered into the online service database.
The general selection procedure is very simple, but the owner of the car will definitely need to enter the initial data. The parameters should be as accurate as possible so that there are no errors or inaccuracies in subsequent results.
You can use this service on our website. The program is freely available, anyone can make calculations in a few minutes. To simplify the process of use, it is worth using the instructions given.
When choosing car tires, it is important to remember that it is of great importance to match the dimension of the tire to the dimension of the wheels. Everything is clear with the diameter - a 15'' tire with a diameter of 15'' should be put on a disk with a diameter of 15''. The confusion usually arises with the width of the tire and rim. Their discrepancy can lead to a number of completely undesirable consequences associated with the operation of tires. The contact patch may become irregular in shape, tire wear may increase, and the handling and driving performance of the car may deteriorate. In order not to make a mistake with the choice - use the correspondence table.
You can also do the calculation yourself. To do this, consider an example for a tire with a width of 215 mm and a diameter of 16.
1) We translate the width of the rubber in cm: 215 mm = 21.5 cm
2) Convert the resulting value to inches: 1 cm \u003d 2.54 inches, divide 21.5 by 2.54, we get 8, 46 - round to 8.5
3) We take 25-30% of the obtained value, in our case: 2.38
4) The resulting number is subtracted from the width of the tire and rounded up to tenths 8.5 - 2.38 \u003d 6.1
5) The rim width of the rim must be 6.1 inches or 155mm.
For discs up to and including 14 inches in diameter, an error of 0.5 to 1 inch is possible.
For discs with a diameter of 15 inches or more, the allowable error is 1.5 inches.
As a calculation, it is better to calculate the allowable value interval, namely, calculate 25% and 30%, where 25% will be the maximum and 30% the minimum width of the disc rim.
Correspondence table for tires and rims for passenger cars
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Ø |
Tire size |
Disc rim width |
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Min. |
Recom. |
Max. |
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Series 80 |
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Series 70 |
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Series 65 |
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Series 60 |
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Series 55 |
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Series 50 |
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Series 45 |
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Series 40 |
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Episode 35 |
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Series 30 |
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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 a 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 a 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 The best option when purchasing a disc is to 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 can easily choose the rims he is interested in and not make a 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.
A disk for operation only in summer can be wider so that the car looks more spectacular on the highway or in a 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, which is often bundled with sports cars or with those European brands whose developers paid special attention not to practicality when replacing a flat tire, but to free space in the trunk, has very hard sides and internal transverse stiffening ribs. 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 maximum weight index 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 side.
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 rubber with a small radius disc on an SUV In order to avoid these mistakes, motorists should study all the technical parameters of 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.
