Some car owners eventually decide to supply discs with a larger diameter than originally envisaged at the factory. On the one hand, the car is being transformed, but behind the aesthetic beauty there is a technical error in the speedometer readings, which many either do not know about, or simply do not take it into account. This is of course everyone's choice, but you must admit that an unpleasant situation may arise when you drive your car, adhere to speed mode, and the traffic police inspector who stopped you claims that you were driving with excess. Whom to believe, inspector or speedometer? Let's figure it out ...
The situation here can be twofold. If the installed tire size and wheel rims complies with the factory standards (approved by the manufacturer), then there should be no problems with the speedometer readings (if, of course, it is serviceable). But if the dimensions differ from those recommended by the manufacturer, then the inspector may be right.
Ideally, after installing non-standard tires, or wheels, or both, on the car at the same time, it is necessary to calibrate the speedometer. By default, manufacturers calibrate speedometers for those standard sizes that are indicated on the car body in the doorway from the driver's side, but if the sizes differ, then the speedometer begins to show not entirely reliable data.
The other day I came across a very interesting little program. The calculator of the error of the speedometer when changing tires and rims is an auxiliary tool for the production correct replacement wheels and tires installed on the vehicle. If you want to change the size of tires or put wheels of a different radius, this program will help you find out how the external indicators will change, calculate the error of the speedometer, show the changes ground clearance car (clearance).
185/60 / R14- factory values of rubber for civilian versions of the 6th generation sivok;
195/55 / R15- factory values of rubber for the generation.
Calculator for speedometer error when changing tires
- 103,1
- 113,4
- 123,7
- 144,4
- 154,7
- 175,3
- 185,6
- 195,9
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New tire size: 145 155 165 175 185 195 205 215 225 235 245 255 265 275 285 295 305 315 325/30 35 40 45 50 55 60 65 70 75 80 85 R 12 13 14 15 16 17 18 19 20 22 |
Attention! Manufacturers and many car services do not recommend installing wide tires on the car during winter season- this is due to the deterioration braking qualities car.
Another useful tool would be a width calculator. car drive since When changing the tire parameters, it is very important to check the compatibility of the wheel width of the wheel installed on the vehicle. In the worst case, you simply will not be able to pull the rubber onto the rim. This small calculator will help you calculate the minimum and maximum wheel widths suitable for the selected tire size.
Calculation of the width of the car rim
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Operating with these two calculators, you can easily determine the standard size automotive rubber or choose new rims for the required tire size.
Perhaps, for today this is all that I wanted to show and tell you.
Attention # 2! The calculator for calculating the error of the speedometer and comparing tire sizes is provided for informational purposes only and does not guarantee 100% correct data. Contact a tire specialist for advice !!!
Thank you for your attention and interest in the project.
To be continued...
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During the selection of new wheels for a car, the question often arises: should I put wheels more or less, or in order to improve appearance auto or cheaper purchase of tires and wheels. But the most important question arises, whether the wheels are suitable for my car and how its characteristics will change. You can understand whether the wheels fit on the gas tank lid or the side stand of the car (photo 1). Or find in our directory the applicability of disks to a car, your car and see the tires recommended by the factory. But it often happens that you can supply other tires that are not officially approved by the factory.
In this case, the main thing is to understand how the speedometer readings will change, i.e. the speed of the car, as the outer radius of the wheel will change. Clearance (ground clearance) will also change. It is not recommended to go beyond the values of the factory tires by more than 2-3%. Vehicle handling and behavior, gas mileage and actual vehicle speed may change.
Tire calculator - size comparison
Our tire calculator will show you the visual difference in diameter, profile, radius, ground clearance and width. Dotted lines indicate size differences. In the upper part, you can see a visual representation of the old tire (original size), and in the lower part, the new tire is visualized. Just as you can see, the tire can be seen in side and front projection. You can copy the URL of the page and show it to other people and they will see the same comparison as you see it.
But how to understand all these values and the difference in%? For this, we have created a tire calculator, it will help to understand the change in all desired characteristics and will show the difference in% between the old and the new tire and even visually display how the wheel of the old and new size will look like. You just need to enter the tire width, profile and wheel radius. Usually they are displayed in this form - 195 \ 65 R15 (photo 2).
How to use the online tire calculator?
Use our online tire calculator very simple. In the upper left corner of the site, there are fields for choosing the tire size. In the top row, you need to indicate the dimension of your original factory tire (or tires that are currently installed on your car). These values are written on the tire profile (sidewall). In the first list, you need to select the tire width - it is indicated in millimeters. The second list is the percentage of the section height to the tire width. The third list is the diameter of the disc in inches (commonly referred to as the radius).
In the bottom row, you need to indicate the size of the new tires. Tires that you are going to install on a car or have already bought. Then click "Calculate". Our tire calculator will calculate the differences between the old and new tires and display them in a table and in a picture. Namely: diameter, width, circumference, tire profile height, number of revolutions per kilometer and change in the car's clearance. The first columns of the table will show the parameters for old and new tires, in the next columns the difference in mm and the percentage difference between them.
There is a speedometer at the bottom of the tire calculator to visually compare the speed of the old and new tire... Under the speedometer, you can increase and decrease the speed and see the change in the speed difference between the old and new tires.
Be careful!
Be careful on the road and follow the manufacturer's recommendations. Reverse side installation is not standard sizes tires, this is the risk of losing insurance in case of an accident, not passing the state technical inspection of the car, since the setting of tires not approved by the factory is considered a change in the design of the vehicle.
With the help of a tire calculator, you can easily calculate how the outer dimensions of the wheel, the height of the ground clearance (clearance), the speedometer readings and other characteristics will change when you install tires with a different standard size on your car. The calculator calculates all tire sizes in millimeters, and the vehicle speed in km / h.
And also the calculator will help to calculate the required rim width for a specific tire size.
How to use the tire calculator:
First enter the standard size installed on your car, and then the one that you want to install and click "calculate". The table on the right shows the results of the calculator's calculations.
Detailed information on tire marking in the section: tire marking.
We recommend that you only install the factory tire sizes that are specified in the operating instructions for your machine. Installation of non-standard sizes may void the dealer's warranty, as well as impair the performance and handling of the vehicle.
Tire calculator for European tires
Old size:
145 155 165 175 185 195 205 215 225 235 245 255 265 275 285 295 305 315 325
/ 25 30 35 40 45 50 55 60 65 70 75 80 85
12 13 14 15 16 17 18 19 20 21 22 23 24
Found in the directory:
175/70 R13 -
175/70 R13 -
When converting tire sizes on a calculator, keep in mind that:
With an increase in diameter wheel rim(and, as a consequence, a decrease in the height of the tire profile so that the outer diameter of the wheel remains unchanged) the load on the car's suspension increases, as well as the comfort deteriorates (the car will become noticeably stiffer).
With an excessive increase in the profile of the tire, the machine becomes a "roll", it is less controllable, and at critical values of the height of the profile, the tire can begin to cling to the parts of the body and suspension of the car, which will subsequently lead to its destruction.
What is a tire calculator for:
With this tire calculator, you can easily calculate how the outer dimensions of the wheel, the height of the ground clearance (clearance), the speedometer readings and other characteristics will change when you install tires with a different standard size on your car.
Old tire size
Width
Height
Diameter
New tire size
Width
Select 5.0 5.5 6.0 6.5 7.0 7.5 8.5 9.5 10.5 11.5 12.0 12.5 13.0 13.5 14.5 125 135 145 155 165 175 185 195 205 215 225 235 245 255 265 275 285 295 305 315 325 335 345 355 365
Height
Select 25 27 30 31 32 33 34 35 38 38.5 40 45 50 55 60 65 70 75 80 85 90
Diameter
Select 12 13 14 15 16 16.5 17 17.5 18 19 20 21 22 23 24 25 26 28 30 32
First enter the standard size installed on your car, and then the one that you want to install.
The difference in speedometer readings and real speed depends on the speed of the car, the higher the speed, the greater the difference
| External dimensions | old | New | Difference | ||
|---|---|---|---|---|---|
| Tire width, mm (A) | 0 | 0 | 0 | ||
| Profile height, mm (B) | 0 | 0 | 0 | ||
| Disc diameter, mm (C) | 0 | 0 | 0 | ||
| Outside diameter, mm (D) | 0 | 0 | 0 | ||
| Change in ground clearance, mm | 0 |
On the website of the online store, the site contains a convenient tire calculator that allows you to easily calculate the changes in wheel parameters when switching to a different tire size. With this online tool, you can calculate the outer measurements of the wheel, ground clearance (ride height), calculate the speedometer readings and other characteristics.
With the onset of the new season, every responsible car owner considers it necessary to change the tires in accordance with the season. The best option will install tires of the size recommended by the automaker for a particular car brand. In cases where this is not possible, deviations in diameter in the 2% range are allowed.
Replacing rubber requires a serious approach. When choosing new tires and wheels, it is necessary to take into account such indicators as:
- tire width,
- profile height,
- inner diameter of the wheel,
- permissible speed indices.
Incorrectly selected tires can cause malfunctions in the car's electronics, increase fuel consumption, deteriorate driving comfort, and also cause problems during vehicle inspection at the traffic police.
How to calculate tires?
To find the correct tire size, you need to use a tire calculator, with which the theoretical dimensions are determined. All measurements are carried out in millimeters, and the speed in km / h. To make a calculation, you must enter the parameters of the tires of your car in the appropriate line. Then enter the dimensions of the new tire and the rim to be installed. After specifying all the parameters in the table below, information about changes in the width of the tire and the height of the profile, the inner and outer diameter, the difference in speeds (real and according to the speedometer readings) will appear.
What to look for when choosing a tire
- Installation of tires and wheels custom size can lead to damage to the tire itself, damage to the wheel and a decrease in the performance of the car. When choosing a rubber, it is better to rely on the recommendations of the automaker.
- If the diameter of the wheel rim is larger, then the load on the suspension may increase. To maintain the same diameter of the outer wheel, the profile height indicators should be reduced.
- If you choose tires with a greatly increased profile, you need to be prepared for a loss in the quality of vehicle handling. The tire can rub against the body and suspension, causing rapid wear.
- Even with the smallest difference between the indicators on the speedometer and in reality, the error can increase significantly with increasing speed, which makes driving unsafe.
- Narrow or too wide rims can deform the tire. This, in turn, will lead to premature wear and poor performance.
Instructions
Look at the nameplate in the driver's side doorway for the recommended tire size. Write it down on paper or memorize it. Find wheels of this size in a car dealer and use a tape measure to measure the outer diameter of the tire. Write this value down on paper. Drive the car into a hole and turn the front wheels out completely: first in one direction and then in the other direction. Measure with a ruler or tape measure the distance from the tire to the nearest structural member and write these values down on paper.
When choosing your favorite tires, consider the diameter of the future rims, and, depending on the size of the future tire, choose the width of the rims. The required disc width is equal to the tread width. It may be easier to find a disc with a slightly larger diameter and the desired width. For example, take rims of 14 inches instead of 13 and pick up tires on them. This option will be even more advantageous in terms of durability, but at the same time more expensive.
Try to buy tires, dimensions which will be about the same as the recommended ones. For example, the manufacturer recommends tires with dimensions 175 / 70R13 86S. 175 is the overall width of the tire in millimeters, / 70 is the height of the tire's profile as a percentage of the width, R-13 is the mounting diameter corresponding to the diameter of the discs, 86 is the load factor, S is the speed index. It is worth noting that the overall width of the tire may differ from the tread width, so if you want a wider tread, then pay attention to this feature. Do not use tires with reduced load and speed ratios.
If you want to put R16 wheels instead of R13 on your car, find a rubber of a suitable width. Since 175mm R16 tires do not exist, it is more realistic to find 215mm and wider tires. Look at your notes and calculate how many centimeters you have left. Increasing the tire width by 1cm more than the recommended one reduces the measured distance between the wheel and the body by 5mm. Please note that it is not advisable to increase the wheel diameter by more than 3 cm, as this will lead to increased consumption fuel and deterioration traction characteristics cars. Please select suitable tires and measure their diameter with a tape measure. Compare with the recommended wheel diameter. If the excess of the recommended dimensions of the future wheel is within the limits of your calculated norm, you can safely buy the selected tires. The speed and load factor in this case will significantly exceed the recommended one, which will have a beneficial effect on the durability of the rubber.
