Are the 245 40 18R and 245 45 18R the same size?

The 245 40 18R and 245 45 18R tires are not the same size. Tires are ring-shaped elastic rubber products that are grounded and rolled on various vehicles or machinery. Usually mounted on metal rims.

It can support the body body, cushion the external impact, realize the contact with the road surface and ensure the driving performance of the vehicle. Tires are often used under complex and harsh conditions, and they bear various deformations, loads, forces, and high and low temperatures when driving, so they must have high load-bearing performance, traction performance, and cushioning performance. At the same time, high abrasion resistance and flexural resistance, as well as low rolling resistance and heat generation are required.

Half of the world's rubber consumption is used in tire production, which shows the ability of tires to consume rubber. Tires are an important part of the car, there are more than 10 kinds of marks on the tires, and the correct identification of these marks is very important for the selection, use and maintenance of tires, and is of great significance for ensuring driving safety and prolonging the service life of tires. Tire specifications.

Specifications are the hallmark data of the geometric parameters and physical properties of the tire. There are three ways to express tire specifications: A

Metric (m); b.Metric Imperial Mixed; c.Inch; Imperial tire specifications are often expressed by a set of numbers, the former number indicates the tire section width, and the latter number indicates the rim diameter, both in inches.

The letter or symbol in the middle has a special meaning: Tire structure: "R" means radial tire, "D" and "one" mean bias tire.

Others:"xl"Indicates the texture of the local strengthened tire,"tg"Indicates an engineering tractor and grader.

Tires (off-road),"nhs"Indicates off-highway tires.

245 40 18R and 245 45 18R are not the same size, 245 refers to the width of the top surface of the tire, 40 is the width of the side of the tire, and 18R refers to the diameter.

The 245 40 18R and 245 45 18R tires are not the same size.

Hello, through the above picture, we can better understand the specifications of tires, and compare 255 40R18 with 245 45R18.

According to the diagram, we know that 255 and 245 refer to the width of the tire, 40 and 45 are the flat ratio of the tire, and 18 is the diameter.

It can be seen that the 255 40R18 tires are 10 mm wider than the 245 45R18 255 tires

The difference in the flat ratio is 5%, and the tires with high flat ratio are relatively comfortable due to the long sidewall and strong cushioning capacity, but the feeling of the road surface is poor, and the lateral resistance when turning is weak; On the contrary, tires with low aspect ratio and large inner diameter have a large ground contact area and a large pressure on the tire due to the short sidewall and wide tread, which is very sensitive to the road surface, strong lateral resistance when cornering, and strong vehicle handling. I hope it will be helpful to you.

255 represents the cross-sectional width of the tire 255 mm, 245 represents the cross-sectional width of the tire 245 mm represents the flat ratio of the tire, which is the percentage of the cross-sectional height of the tire divided by the width of the tire, R represents the radial tire, and 18 represents the rim diameter of 18 inches.

In the case that the flat ratio and the size of the wheel have not changed, the width of the tire will be increased, and the corresponding increase will be added

The outer diameter, for example, is about centimeters smaller than that of 245 45 18, which will cause a certain error in the speedometer reading, but the change in the outer diameter is less than 3% is still in the acceptable range, so it is okay to change 245 45 18 to 255 45 18.

Changing the tire model needs to remember a more important data range, that is, the error value of the new and old wheel tires should be controlled within the 3% range, if it exceeds this range, it will lead to a decrease in the handling of the vehicle, the braking distance will become longer, and the tire will collide with the wheel arch when the vehicle is turning. Replaceable. The difference between the diameter of the old and new tires is:

The error value should be controlled to 3%)

All are 245 18-inch tires with a width.

The difference is that the thickness is different from one 45 to one 50

The 45 handles better, but the 50 is more comfortable.

Generally, the front and back are the same.

My BMW 7 Series wheels are equipped with 245 45R18, and it stands to reason that it should be equipped with 245 50R18

Is it a BMW? Yes, no problem. It is best to use explosion-proof, Pirelli tires are the original BMW car supporting Oh,

Hello! 245 = cross-sectional width of 245 mm.

50 = 50% aspect ratio

45 = 45% aspect ratio

r=radial tire structure18=rim diameter is 18 inches 245 50R18 theoretical outer diameter:

225 55R16 Theoretical Outer Diameter:

We recommend that the specifications of the tires you buy must be consistent with the specifications of the tires assembled in the original car, and if you need to change the tire specifications, you must go to a professional tuning shop for tire upgrades, or consult the car manufacturer.

If you have a car with the same specifications with four tires, we do not recommend using a different specification from the front and rear, which will affect the vehicle. Because the front and rear axle tires are different, the grip of the front and rear axle tires is different, or the outer diameter of the tires is different, causing handling or mechanical problems, especially in 4WD vehicles.

235 represents the cross-sectional width of the tire 235 mm, 45 represents the flat ratio of the tire, which is the percentage of the cross-sectional height of the tire divided by the width of the tire, r represents the radial tire, and 18 represents the rim diameter of 18 inches.

The size of the tire is printed on the sidewall, and there are two ways to express it, such as 34*7 or so on. The former is a high-pressure tire and the latter is a low-pressure tire. In addition, there are many notations, such as D for light cars, F for medium-sized cars, G for standard cars, and H, L, and J for large luxury and high-performance cars.

If an R is printed on the sidewall, such as 175R13, it means that the tire is a diameter tire, 175mm (inches) wide and long, and is mounted on the wheel with a diameter of 13 inches (330mm) on the wheel, and the word radial is generally engraved.

The international standard tire code indicates the percentage of cross-sectional height and aspect ratio in millimeters. After that: tire type code, rim diameter (inches), load index (allowable load quality code), allowable speed code.

For example: 175 70R 14 77H in 175 represents the tire width is 175mm, 70 means that the flat ratio of the tire section is 70%, that is, the section height is 70% of the width, R represents the radial tire, the rim diameter is 14 inches, the load index is 77, and the allowable speed is H level.

235 - Tire width. The 45-to-aspect ratio is the width of the side of the tire. R-radial tires. 18-rim width 18 inches.

In 45R18, 245 represents the tire width is 245mm, and 45 represents the flat ratio of the tire section.

is 45%, that is, the cross-sectional height is 45% of the width, and R18 represents the rim.

The diameter is 18 inches.

In the 45ZR18, 245 represents the tire width is 245mm, the 45ZR tire can travel at a maximum speed of more than 240km h, and the R18 represents the rim diameter is 18 inches.

The wheels of the car generally use radial tires.

Specifications for radial tires include width, aspect ratio, inner diameter and speed limit symbols and are auspicious. Take the Toyota sedan as an example, its tire specifications.

It is 195 65R15, which means that the width between the two sides of the tire is 195 mm, 65 means the aspect ratio, and "R" stands for the word radial, which means that it is a radial tire.

235 55 R18 and 235 65 R18 Two tires 235 65 R18 are taller, both tires are 18 inches in diameter, the same height. But the flat is bigger than the 65 and the 55 means the 65 has thicker tires, so it's a bit taller than the 55.

235 means the cross-sectional width of the tire 235mm; 55 or 65 represents the flat ratio of the tire, which is the percentage of the cross-sectional height of the tire divided by the width of the tire, the greater the value, the thicker the tire, the lower the maneuverability, but the comfort increases; R stands for tire type, radial tire, and R18 stands for hub diameter 18 inches.

The flat ratio is a piece of data for tires that represents the percentage of the height of the tire's cross-section to the maximum width of its cross-section, which is simply the height-to-width ratio of the tire.

For example, a tire with a size of 205 60 R15 means that its maximum cross-section width is 205 mm, the aspect ratio is 60%, and the inner diameter is 15 inches.

The flat ratio is 60%, that is, the cross-sectional height of the tire is 205*60%=123mm.

The tire cross-section is composed of shoulder, sidewall and toe, and the sum of the three heights is the tire cross-sectional height.

It is not recommended to change. The reason why the flat ratio of the tire can not be changed:

1. The specifications of the tires purchased should be consistent with the specifications of the tires assembled in the original car, and it is best not to replace them at will;

2. The difference between the flat rate of 60 and 65 is that the flat rate of 65 is higher, and the tire with high flat ratio has a high comfort rate due to the long sidewall and strong cushioning capacity, but the feeling of the road surface is poor, and the lateral resistance when turning is weak;

3. On the contrary, tires with low flat ratio and large inner diameter have a large ground contact area and a large pressure on the tire due to the short sidewall and wide tread, which is very sensitive to the road surface, strong lateral resistance when cornering, and strong vehicle handling. After the vehicle is equipped with tires with large width, large inner diameter and low aspect ratio, in addition to strong handling, the appearance and visual effect also give people a very powerful feeling.