If you want to modify the wheels, do you really understand the ET value of forged aluminum alloy wheels?

Today, I will explain a more professional data: ET value. This is not an alien (ET) sitting on a UFO. The ET in the wheel is also called Offset. The Chinese name is: wheel offset, which is a very important loading parameter of the wheel. It determines whether the wheel will be in contact with the wheel eyebrow. Shock absorbers, calipers and other vehicle parts scratch.

When refitting wheels, not only look at the aesthetics and basic dimensions, but also the ET value. A perfect ET value can make your truck look more coordinated, and at the same time, you can clearly feel more stable during driving.

What is the ET value?

It refers to the distance from the mounting surface of the rim to the centerline of the rim.

A positive offset means that the joint surface is closer to the spoke side of the hub; on the contrary, a negative offset means the joint surface is closer to the inner side of the car. Based on the above, it can be inferred that when the offset is 0, the hub mounting surface coincides with the center line.

How to measure ET value? The measurement of the ET value is actually very simple. First, place the tire on the ground and use a straight object (A) across the diameter of the tire. Then measure the distance between A and the ground to get the distance B; then measure A The distance between the mounting surface of the wheel and the hub is the distance C; finally, the distance C-0.5*distance B = ET value

The relationship between offset and wheel track When replacing a wheel hub, the choice of ET value is particularly important. Different choices of ET value will directly affect the wheel track. The larger the ET value of the wheel hub is: the more the wheel hub is recessed to the inside of the car, the smaller the track between the two hubs at this time; the smaller the wheel hub's ET value is: the more the wheel hub protrudes toward the exterior of the car, at this time the distance between the two hubs The wheelbase becomes larger.

Take a "chestnut", the original wheel hub has an ET value of 45mm. When refitting, it is replaced with a rim with an ET value of 35mm. The centerline of each rim is moved out by 10mm, then the wheelbase of the car will increase to 20mm. . When the wheelbase changes, it will bring advantages and disadvantages to the car.

Advantages: The stability will be improved at high speeds or sharp turns.

Disadvantages: reduced flexibility, increased turning radius, direction sinking, kingpin offset change, vehicle suspension geometry change, roll center change, etc.

All in all, the ET value of the wheel, the track, and the driving situation of the vehicle, they are like dominoes, which affect the whole body.

In addition to the above-mentioned wheelbase, all suspension geometrical parameters will be affected by the ET value, such as tire grinding radius, suspension leverage ratio, wheel bearing force, lateral position of the tire, and the life of suspension parts, etc., will have a joint effect. Therefore, before you choose those wheels with inappropriate ET values and exaggerated sizes, you still need to think twice.