When the steering wheel vibrates and the tire has partial wear and tear, it could be caused by problems with the wheel alignment. When the car is first shipped, the wheels are well aligned, but can shift as you drive it. At this time, the process of realigning the wheel is called wheel alignment. 
This is especially important when the wheel or tire is raised up or when the car is lowered through system suspension tuning. Moreover, it is good to realign or check the wheel alignment when purchasing a used car. 
The effect of wheel alignment ranges from fuel saving, longer tire life, safety and comfort, prevention of vibration and shifting of steering wheel, longer life of suspension parts and parts related to maneuvering control. 
There may be cases when you do not encounter any issues for a long period of time. But if you drive frequently on roads where the road condition is not good or have had a big impact, it can shift in one day. It is recommended to align the wheel every 20,000 km for maintenance and prevention. 

当方向盘出现震动，并且轮胎出现局部磨损时，这可能是由车轮定位方面的问题导致的。汽车在刚出厂时，车轮的定位是良好的，但在驾驶过程中，车轮定位可能会发生偏移。此时，重新调整车轮位置使其恢复正确定位的过程就被称为车轮定位。

当车轮或轮胎被抬起，或者通过调整车辆的悬挂系统降低车身时，进行车轮定位尤其重要。此外，在购买二手车时，对车轮进行重新定位或检查车轮定位情况也是很有必要的。

四轮定位的作用包括节省燃油、延长轮胎使用寿命、保障行车安全与驾乘舒适性、防止方向盘震动和跑偏，以及延长悬挂部件和与操控控制相关部件的使用寿命。

可能会出现这样的情况，即你在很长一段时间内都不会遇到任何问题。但如果你经常在路况不佳的道路上行驶，或者车辆曾受到过强烈撞击，车轮定位可能在一天之内就会发生偏移。建议每行驶20000公里进行一次车轮定位，以起到维护和预防的作用。

 Limit of tire wear and braking distance The braking distance depends on the speed of the car, the load, the slope of the road, wind, brake condition, the time between the point of stepping on the brake and the brake working (the time the car runs until the brake starts working), etc. 

Tire wear is also another important factor in deciding the braking distance. The tire wear is measured by the depth of the tread that does the surface, and when the tire reaches the wear index, the depth becomes 1.6 mm. The tire that reaches the wear index must be immediately replaced because if it is continuously used, the braking distance will be longer, thus it will be easier to slip and the tire can easily be damaged because of an alien substance that penetrates or an external impact that causes hydroplaning. This will make it difficult to brake and operate the steering wheel. 
Tire rotation even with the degree of tire wear, and the difference between front and rear tire wear also greatly affect the handling and safety of the car. Generally, because the engine and the driver seat are located in the front side of the car, the front tires typically get more load than the rear tires. Because the front tire creates friction with the road surface when stopping or starting (front wheel drive), the front tires are worn faster than rear ones. Also, because the front wheels are tilted inside due to the camber angle, it puts more load on the outer side of the tire rather than the inner side. However, the rear tires change the contact force of the inner and outer, depending on the surface of the road.

Therefore, it is necessary to rotate the tire locations periodically so that the weight of the tires ­—the inner and outer sides of the front and rear wheels— will be averaged to form a balance of wear. Appropriate tire rotation can also increase the life of the tires. If you periodically rotate the tires, not only can you check the abnormal wear and damage on the tires, but also effectively manage the tires.  

轮胎磨损限度与制动距离 制动距离取决于汽车的行驶速度、负载、道路坡度、风力、刹车状况，以及从踩下刹车到刹车开始起作用之间的时间（即从踩下刹车到刹车实际开始工作期间汽车行驶的时间）等等因素。

轮胎磨损也是决定制动距离的另一个重要因素。轮胎的磨损程度是通过起作用的胎面表面的深度来衡量的，当轮胎达到磨损指示标记时，胎面深度变为1.6毫米。达到磨损指示标准的轮胎必须立即更换，因为如果继续使用，制动距离将会变长，这样就更容易打滑，而且由于异物刺入或者导致轮胎水滑的外部冲击力，轮胎也很容易损坏。这会使得刹车变得困难，同时也会增加方向盘操作的难度。

即使考虑到轮胎的磨损程度，轮胎的换位以及前后轮胎磨损程度的差异，也会极大地影响汽车的操控性和安全性。一般来说，由于发动机和驾驶员座椅位于汽车的前部，通常前轮所承受的负荷要比后轮更大。因为在前轮驱动的情况下，前轮在车辆制动或启动时会与路面产生摩擦，所以前轮的磨损速度比后轮更快。此外，由于前轮因外倾角而向内侧倾斜，轮胎外侧所承受的负荷要比内侧更大。然而，后轮的内外侧与路面的接触力会根据路面情况而发生变化。

因此，有必要定期对轮胎进行换位，这样一来，前后车轮的内外侧轮胎所承受的重量就能平均分布，从而使磨损达到平衡状态。合理地对轮胎进行换位还可以延长轮胎的使用寿命。如果你定期对轮胎进行换位，不仅能够检查出轮胎上的异常磨损和损坏情况，还能有效地对轮胎进行维护管理。

The left/right asymmetric tires refer to the tires with different left and right shape, which are designed to maintain optimal performance on the contacting surface by analyzing each function dynamically including the control stability, water drainage, braking force, riding comfort etc. This is usually applied to the UHP (Ultra High Performance) tire with maximized high speed handling and recently it has been widely applied to the crossover RV. 

1) The outer part must face the outer side during installation.Because the left/right asymmetric tire has a different shape (pattern) and function (inner – comfort/outer – handling) for the left and right tire, based on the center of the tire, you must install the tire sidewall marked "OUTSIDE" to the outer side for correct driving performance.

2) Unlike the V shape pattern (directional), the driving direction is not limited to one direction. For example, if one tire has been worn out partially due to poor alignment, you can just exchange the location of the opposite side or front and rear. As long as the part marked OUTSIDE is installed on the outer side, it is designed to perform whichever direction it is installed. 

3) The spear tire is convenient.The V shape pattern has a disadvantage of having to carry up to two spare tires, depending on the connection location with the wheel, but for the left/right asymmetric tire, you only need to align the OUTSIDE part to the outer side and can carry less spare tires. 

左右非对称轮胎是指左右形状不同的轮胎，其设计目的是通过动态分析包括操控稳定性、排水性、制动力、驾乘舒适性等各项功能，从而在轮胎与地面的接触面上保持最佳性能。这种轮胎通常应用于超高性能（UHP）轮胎，这类轮胎将高速操控性能发挥到了极致，并且近来也被广泛应用于跨界多功能车（RV）上。

1) 在安装时，外侧部分必须面朝车辆外侧。由于左右非对称轮胎以轮胎中心线为基准，其左右两侧（花纹）形状不同且功能各异（内侧侧重舒适性，外侧侧重操控性），所以你必须将标有“OUTSIDE”（外侧）字样的轮胎侧壁安装在车辆外侧，以确保实现正确的行驶性能。

2) 与V形花纹（方向性花纹）不同，（左右非对称轮胎的）行驶方向并不局限于一个方向。例如，如果因为车轮定位不佳导致某一个轮胎出现了局部磨损，你只需将其与另一侧或前后位置的轮胎进行换位即可。只要标有“外侧（OUTSIDE）”的那一面安装在外侧，那么无论以何种方向安装，这种轮胎都能发挥其设计性能。

3) 非对称花纹轮胎（这里spear tire 推测为表述有误，结合前文应指左右非对称轮胎）使用起来很方便。V形花纹轮胎存在一个缺点，即根据其与车轮的连接位置，可能需要携带多达两个备用轮胎。但对于左右非对称轮胎，你只需将标有“外侧（OUTSIDE）”的那一面安装在外侧就行，这样就可以减少备用轮胎的携带数量。

These are the speed level symbols showing the maximum safe speed of the tire.

When you look at the sidewall of the tire, it has various symbols for load index and rim diameter (inch), tire structure, aspect ratio, cross sectional width etc.

For example, if it is marked P245/45R18 102Y for a tire, P stands for Passenger, 245 for cross sectional width (W) contacting the road surface, 45 for aspect ratio (it is typically called series and means the rate of height to width of the tire),R for radial tire, 18 for internal diameter of the tire (rim diameter), 102 for load index (maximum load index one set of tire can stand), and Y for maximum safety speed.

Maximum safety speed refers to the maximum speed the tire can run within the safe range. It is marked with an alphabet. The speed symbol is ranges from A–Y. The higher the alphabet, the higher the speed, which also refers to a higher performance tire. For the passenger car, it may differ by the car type but generally, the grades Q to Y are assigned. 

The speed level of H means 210 km/h orbelow and W means 270 km/h or below

这些是速度等级标识，表明了轮胎的最高安全行驶速度。

当你查看轮胎的胎侧时，会看到上面有各种标识，分别代表着负荷指数、轮辋直径（单位为英寸）、轮胎结构、扁平比以及断面宽度等等信息。

例如，如果一个轮胎上标记为“P245/45R18 102Y”，其中“P”代表乘用车轮胎；“245”表示与路面接触的轮胎断面宽度（W）；“45”是扁平比（通常称为系列，指的是轮胎高度与宽度的比率）；“R”表示子午线轮胎；“18”是轮胎的内径（轮辋直径）；“102”是负荷指数（即一套轮胎能够承受的最大负荷指数）；“Y”则代表最高安全速度。

最高安全速度是指轮胎在安全范围内能够行驶的最高速度。它是用字母来标记的。速度标识的范围从A到Y。字母越靠后，速度就越高，这也意味着轮胎的性能越好。对于乘用车而言，虽然可能因车型不同而有所差异，但一般来说，使用的是从Q到Y这些等级的速度标识。

速度等级“H”意味着最高时速为210公里或以下，而“W”意味着最高时速为270公里或以下。

This refers to the phenomenon of gliding on the water as if riding a water ski. 
The tread, which is the contacting surface of the tire, has grooves that are designed to make the water flow between them. When driving in the rain, the tire rotates on the surface to push the water away, and when the tire is rotating in high speed, it reduces the function of draining the water using the grooves to form a hydroplaning effect between the tire and the surface of the road. The pressure of the water under the tire and the gravity acting on the tire removes the contact to make it glide on the water like a water ski. At this time, it is not rolling on the road but gliding on the water. This phenomenon is called hydroplaning. 
Hydroplaning occurs severely when the tire is worn out, or the air pressure of the tire is not adequate. It is good to replace the tires with depth of less than 1.6 mm. 

这指的是一种就好像踩着滑水板那样在水面上滑行的现象。

轮胎的胎面，也就是轮胎与地面的接触表面，有一些凹槽，其设计目的是让水在凹槽之间流动。在雨中行车时，轮胎在路面上转动以将水排开，而当轮胎高速转动时，它会降低通过凹槽排水的功能，从而在轮胎和路面之间形成水滑效应。轮胎下方水的压力以及作用在轮胎上的重力会使轮胎与路面失去接触，进而让轮胎像滑水板一样在水面上滑行。此时，轮胎不是在路面上滚动，而是在水面上滑行。这种现象就被称为水滑现象。

当轮胎磨损严重，或者轮胎气压不足时，水滑现象会更加严重。最好更换胎面深度小于1.6毫米的轮胎。

This refers to the waving phenomenon that occurs during high speed driving.
When the car is driving on the road, the contacting surface is not an arc but a straight line. But because the tire has a strong elasticity, it recovers as soon as it gets off from the contacting surface. 
When the tire rotates at a high speed before the deformation from the contact with the surface of the road recovers the next deformation occurs, making a wave shape to be buoyed. When this vibration becomes the same frequency as the rotating speed, the wave seems like it is still. This is called the standing wave phenomenon. 

这指的是在高速行驶过程中出现的（轮胎）波浪状变形现象。

当汽车在道路上行驶时，（轮胎与路面的）接触表面不是弧形的，而是呈一条直线。但由于轮胎具有很强的弹性，一旦它离开接触表面，就会恢复原状。

当轮胎高速转动时，在因与路面接触而产生的变形恢复之前，下一次变形就发生了，从而形成一种呈波浪状鼓起来的形态。当这种振动的频率与轮胎的转动速度相同时，波浪看起来就好像静止不动一样。这就被称为驻波现象。

 Because the appropriate air pressure level differs by the car, please refer to the owner"s manual. 

由于合适的胎压数值因车型而异，所以请查阅车辆的用户手册。

When you look at the side part of the tire, you can see the following symbols 
DOT H2 A7 YHB 3203 
If you read the numbers part of the code, you can identify the manufactured date. 

* 03: Manufactured year. 2003 
* 32: Manufactured week. 32 weeks.  

当你查看轮胎的侧面时，你会看到以下这些标识。

DOT H2 A7 YHB 3203 

如果你读取编码中的数字部分，你就能确定（轮胎的）生产日期。

* 03: 生产年. 2003 

* 32: 生产周. 32 weeks.  

fIt is the tire of the future that you can safely drive when the tire is flat.

The future car will be equipped with state of the art IT functions and we can easily imagine that it will be a much safer car. There is some good news for the people who dream of cars flying in the sky, swimming in the water and drivingeven with the gun shot to the tire as can be seen in the 007 movies. At least the dream is becoming reality for the tire.

Recently the UHP (Ultra High Performance) tires with increased safety at high speed are gaining explosive popularity. Now the tire exceeds the safety of the UHP tire in normal conditions and the run-flat tire will be the future tire to succeed the UHP.

The basic concept of the run-flat tire is that it can drive at maximum speed of 80km/h for an hour even with a flat tire.

A flat tire was directly linked to an accident in the past and usually the driver had to stop or if not, it caused damage to the expensive wheel and other suspension. The run-flat tire is a great tire for drivers who drive long distances frequently, who cannot replace the spare tire or who are female drivers. 

它是未来的一种轮胎，当轮胎缺气时你也能够安全地驾驶。

未来的汽车将配备最先进的信息技术功能，我们可以很容易想象到，它会成为一辆安全得多的汽车。对于那些梦想着能拥有像在007系列电影中那样，能在天空中飞行、在水中行驶，甚至在轮胎被子弹击中后仍能继续行驶的汽车的人来说，有一些好消息。至少，就轮胎而言，这个梦想正在成为现实。

最近，那些在高速行驶时安全性更高的超高性能（UHP）轮胎正迅速走红。如今，有一种轮胎在正常情况下的安全性超越了超高性能轮胎，而防爆轮胎将成为接替超高性能轮胎的未来之选。

防爆轮胎的基本概念是，即使轮胎漏气，它也能够以最高每小时80公里的速度行驶一个小时。

在过去，轮胎漏气直接会引发事故，而且通常情况下司机不得不停车，否则就会损坏昂贵的车轮和其他悬架部件。对于那些经常长途驾驶、无法更换备用轮胎的人，或者女性司机来说，防爆轮胎是一种非常出色的轮胎。

The winter tire maximizes the contacting force and the towing ability on snowy or icy roads through tread rubber and pattern design.

By inserting Kerf inside the tread block, the winter tire maximizes the contact surface. But the summer tire uses the new material, silica rubber to optimize the towing power by maintains the flexibility in the low temperature unlike normal rubber.

The winter tire can be classified into the tires with the spikes to increase the towing ability and friction and the studless tire utilizing the simple tread rubber material and pattern design. Of course, the tires with the spikes show better performance but as you deviate from the snow road, the riding comfort and noise performance is disadvantage in the snow. 

冬季轮胎通过胎面橡胶和花纹设计，将在积雪或结冰路面上的附着力和牵引力发挥到了极致。

通过在胎面花纹块内嵌入刀槽花纹，冬季轮胎最大限度地增大了接触面积。而夏季轮胎则使用了新材料——硅橡胶，与普通橡胶不同，这种材料在低温下仍能保持柔韧性，从而优化了牵引力。

冬季轮胎可分为带防滑钉的轮胎和无钉轮胎，带防滑钉的轮胎可增强牵引力和摩擦力，无钉轮胎则利用单纯的胎面橡胶材料和花纹设计。当然，带防滑钉的轮胎性能更优，但当车辆驶离雪地道路时，其驾乘舒适性和噪音表现方面在雪地行驶时的优势就不复存在了（即在非雪地路面上，驾乘舒适性变差且噪音较大）。