The Upgrading Of Wheel and Tire
The upgrading of rims and tires is one of the basic projects for car modification. Whether you like power upgrades or friends who like to improve handling, you need to upgrade the tires and rims of the vehicle, because the modification of tires and rims is not only a most direct way to reflect the personality of the owner, but only improved Only the specifications of the rim and tire can effectively increase the grip of the tire and prevent the tire from slipping out of control.
In addition to the purpose of replacing rims, the most important thing for car owners is to pursue a variety of appearance changes or to meet special functional requirements. If it is purely for the pursuit of change in appearance, in addition to the original size rims, most people will choose to increase the size of the rims, because the large rims are more visually beautiful, and at the same time can respond to the increased size of tires, provide Better handling and stability can be described as killing two birds with one stone.
Another replacement is to pursue lightweighting of the rims to reduce the suspension weight of the vehicle itself. This can effectively improve the response speed of the steering, suspension and braking parts of the vehicle, and greatly improve the handling. However, due to the strict selection of the material of the lightweight rim itself and the high level of manufacturing process requirements, the cost will be higher than the average rim, and the price will be more expensive. And the lightweight design will cut away the extra parts of the rim, so the appearance design will also look a lot monotonous. Generally, the models with competitive tendency will choose the lightweight modification of the rims.
The manufacturing methods of common aluminum alloy rims can be divided into forging, casting and spinning. Among them, the most rigid and lightest is the forging method. The so-called forging means that the entire aluminum ingot is extruded at one time through a die weighing more than 1,000 tons. This will average the overall density of the rim, increase the material strength, and reduce weight. Taking a 15-inch aluminum alloy rim as an example, the weight of a product produced by a professional rim manufacturer can be controlled at 3.6 to 3.8 kg, which can be more than half as light as other manufacturing methods, but the manufacturing cost is 4 to 5 times higher than that of casting. . As for the low-pressure casting, it is a more compromised method. The manufacturing process is to melt aluminum and other metal alloys into a liquid at high temperature, and then inject it into the mold. This can not only achieve the purpose of high strength and light weight, but also control manufacturing costs. It is the mainstream manufacturing process of most conversion rims.
When choosing the aluminum alloy rim to be replaced, in addition to choosing the style you like, you must also pay attention to the relationship between the shape of the aluminum ring and the heat dissipation efficiency. The shape of the rim determines the heat dissipation efficiency of the braking system, so it is critical to choose a rim of a reasonable shape. Here we help you analyze the relationship between some common rim types on the market and heat dissipation.
1. The traditional multi-claw type adopts the traditional thin strip five-claw or six-claw type design, which belongs to the classic look-resistant style. This design is very helpful for the heat dissipation efficiency of the braking system. As for some three-claw or four-claw style rims, although they can better dissipate heat, because there are too few support spokes, the domestic road conditions are too poor, and their ability to resist distortion, impact resistance and strength is worrying.
2. The radiation line type adopts multi-spoke type, even the shape design similar to the shape of a tree branch. It feels very sporty, and its balanced and symmetrical hollow space is very helpful for heat dissipation.
3. The cover type uses a plurality of large-area spokes, which has a luxurious and high-end feel, but it has no effect on the heat dissipation function. Some of them will have a heat-collecting effect because of the shape.
In order to ensure the safety of the wheel modification and improve the comfort of the modification, we need to understand the relevant parameters of the modified wheel and the correlation of the wheel tires.
1. Rim offset (offest value): It is the distance between the rim screw fixing surface and the geometric centerline (the centerline of the rim cross section). To put it simply, the rim middle screw fixing seat and the entire rim The difference between the center points is whether the rims are retracted inwardly or outwardly after changing. Positive for normal RVs, negative for a few vehicles and some Jeep. For example, the offset value of a car is 40. If it is replaced with 45 aluminum rims, it will shrink into the wheel arch more than the original rims. This data has a relationship with the steering characteristics of the vehicle and the angle of wheel alignment. An excessively large offset value may lead to abnormal wear of the tire, easy bearing wear, and even runaway tires at high speeds.
2. PCD value and hole position: The hole position refers to the number of screws and nuts locked when the rim is fixed, which is generally 4 holes or 5 holes. The PCD value is the diameter of the circle formed by connecting these holes, and the parameters must be the same during installation. German cars are mostly 5 holes, such as Mercedes-Benz is 5 × 112mm, BMW is mostly 5 × 120mm. .
3. Diameter of the rim: Enlarging the rim to improve the performance of the car is currently a popular upgrade. With the tire outer diameter unchanged, increasing the rim to match a wide and flat tire can effectively reduce the lateral swing of the car. To improve vehicle stability. When turning, it is like a dragonfly drenching water, passing lightly. However, it should be noted that the larger the rim, the flatter the tire, the worse the vibration absorption performance, and the greater sacrifice in comfort. Generally speaking, it is most appropriate to increase the size by one or two according to the size of the original rim.
4. Wheel rim width: usually expressed in 5.5J, 6J, 7J, the unit is inch, and the groove shape is J type. Generally, when a 195mm wide tire is selected, a 6-inch rim is required, and a 215mm wide corresponds to a 7-inch rim.
5. Center hole: When installing the rim, the center hole of the rim needs to match the center of the wheel axle, and the models of different brands are different. Like BMW's 72.5mm and Audi's 57mm, if the center hole of the rim is too large, you need to install a center hole collar, otherwise the rim will shake when turning.
In addition, when replacing aluminum rims, you should determine whether the quality is reliable. It is best to pass quality certification products or internationally renowned brands, so as not to threaten driving safety due to the poor quality of aluminum rims. Well-known certifications such as German TUV, Japanese VIA / JWL and American DOT-T. Although these certifications are not the same, they all ensure the excellent quality of the rims. In addition, after modifying the tires and rims, four-wheel positioning should be done to avoid deviations or tire wear.
After changing the aluminum ring, you must first check whether the wheel frame will wear the brake cylinder, vibration damping or suspension system components. In addition, to increase the size of the rim requires an idea, the bead cannot protrude from the front fender, so as to avoid friction between the tire and the fender when driving or steering, which will damage the tire or even cause a dangerous accident such as a flat tire. Secondly, after exercising for a period of time, it is necessary to regularly check whether the balance weights and nuts are loose or fall off.
In addition, whether the tire wall has abnormal expansion, usually this phenomenon is caused by a violent impact here, the wire of the tire wall is broken, of course, the roundness of the rim at this position will also be affected. This is a direct method to check if the rim is deformed. If there is a crack in the rim, even if repair welding is performed, the strength will be greatly reduced. As long as it collides again, it will break again at any time, so it is better to replace it for driving safety.
Tires and rims are inseparable. Only a comprehensive and reasonable upgrade can achieve the ideal conversion effect. There are two principles for tire upgrades:
1.The circumference is unchanged
The most important thing in changing a tire is to first determine the specifications of the original tire. Changing tires with different specifications will affect the accuracy of the odometer and the performance will not be perfect. Each tire has its own specifications. Without considering the tire brand, model, and performance, at least the standard specifications of the original tire must be confirmed. The size of the tire's circumference will affect the accuracy of the meter, so whether it is to maintain the original specifications or replace a wider tire, the premise of not changing or changing the tire's circumference as little as possible. The circumference is calculated by multiplying the diameter of the circle by the circumference ratio. In other words, the only variable that affects the size of the tire circumference is the tire diameter.
How to calculate the tire diameter? It is very simple, it is "rim diameter + tire width x flat ratio x2", taking the most common tire size 185 / 65R14 in the current domestic car as an example:
14 inches (rim diameter) x 25.4 + 185 mm (tire width) x 0.65 (flat ratio) x 2 = 355.6
Mm + 240.5 mm = 596.1 mm, this is the tire diameter (14x25.4 is the conversion of inches to millimeters).
If you do not replace the tires with the same specifications, but you want to widen and enlarge the tires, you can use the above formula to calculate, as long as the tire diameter error is within 2%, it is an acceptable range.
In addition, the width of the tire must also be considered. If you don't care about performance and visual effects and just want to save fuel, you can change to a narrower tire. Most consumers will widen and widen the tire, so that the visual effect, tire grip (coefficient of friction) and tire wall deformation will be improved. Although it is accompanied by an increase in fuel consumption and an increase in road noise, this sacrifice is worthwhile compared to the improvement in grip and stability after replacement.
2. Driving style and driving environment
After the specifications are determined, the actual driving situation must be considered next.
If you drive only for pure daily mobility, or if you often drive long distances, then the comfort and quietness of the tires must be the focus. Comfort-oriented tires are a good choice. The flatness ratio of this type of tire is not too low (at least 0.55 or more), the pattern is relatively fine (symmetrical or non-single-oriented tire pattern) and the sidewall is soft.
If you like to drive fast, often make high-speed corners, start quickly, and brake suddenly, then tire performance is more important. At this time, you must sacrifice some driving comfort and tire abrasion resistance (mainly mono-directional tread pattern). Of course, the price of high-performance tires will also be relatively high.
If you are in a wet and rainy area, the drainage of the tires will be particularly important. For safety reasons, it is recommended that you choose a set of rain or wet tires.
If you are located in an area that has snow all year round, it is best to choose snow-resistant tires to increase the contact area or improve the grip.