Bracket parts to control roll volume


Suppresses left-right misalignment of axles and contributes to reduced roll

Lateral up bracket

The angle of the lateral rod is corrected horizontally by raising the mounting position of the lateral rod on the hosing side.

As the angle approaches horizontal, the left-right misalignment of the axle that occurs when the vehicle height changes can be suppressed.

In addition, the roll center position is compensated upward, which is expected to have the effect of reducing the amount of roll.

Advantages of changing the lateral rod mounting position with the lateral up bracket

Center of gravity shift by lifting

Lifting a vehicle does more than simply increase the height of the vehicle; it has a number of effects on the vehicle.For more information on lifting, see"What Happens in Lifting.

Among the various changes, we will focus here on the shift of the center of gravity due to lifting.

When a car is lifted from its normal ride height, the overall center of gravity of the car is also raised. And with a higher center of gravity, the control and behavior of the car also changes.

Lifting the vehicle raises the vehicle height and at the same time raises the center of gravity.

Mechanism of increased roll volume due to lifting

When the center of gravity is raised by lifting, the distance between the center of gravity and the roll center (*1) is increased. This distance between the center of gravity and the roll center is the "roll moment" (=roll amount). The larger the roll moment, the more the body will roll to the left or right.

For link-type rigid-axle vehicles, the roll center is obtained at the intersection of the two lines below.
-Line connecting the center of the right tire ground surface and the hosing side fixed part of the lateral rod.
-Line connecting the body side fixing part of the lateral rod and the center of the left tire ground surface

In addition, when the vehicle is lifted, the lateral rods, which were nearly horizontal, are angled, and the roll center shifts from the center of the vehicle to the left side of the vehicle. This bias causes the left and right sides to behave differently when cornering, with the left side leaning heavily on left corners and the right side holding relatively firm on right corners.

The further away the center of gravity and roll center are, the more roll is felt. Also, when the vehicle is lifted, the roll center position moves to the left, resulting in different behavior from left to right when cornering.

Lateral rods are originally designed to suppress lateral forces. However, the more they are angled, the more easily they transmit thrust (vertical force) from the road surface to the vehicle body. In other words, when the lateral rods are angled due to lifting, the ride quality will deteriorate.

To compensate for the lateral rod angle in the horizontal direction, a bracket can be added to the lateral rod mounting to offset the mounting position upward or downward to bring it closer to horizontal.

The up bracket is attached to the hosing side of the lateral rod (left side of the figure) to compensate upward. The down bracket, on the other hand, is attached to the body side of the lateral rod (right side of the figure) to compensate downward.

Difference between up-bracket and down-bracket

Correction brackets include lateral UP brackets that raise the mounting position on the hosing side and lateral DOWN brackets that lower the mounting position on the body side.

So which should we choose, up-bracket or down-bracket?

Both have the same effect of bringing the lateral rods closer to horizontal, but the roll center is what we want to consider here. The fixed position of the lateral rods affects the roll center of the vehicle and should be chosen with care. In correcting the roll center alignment, it is not a simple matter of lowering the amount of lifted up.

First, the up bracket raises the roll center. The down bracket, on the other hand, conversely lowers the roll center.The closer the distance between the roll center and the center of gravity, the smaller the roll moment (=roll amount). Therefore, raising the roll center with up brackets and bringing it closer to the center of gravity will reduce the increase in roll amount due to lifting.

Up bracket is recommended to control roll volume

A possible reason for choosing a down bracket instead of an up bracket is to correct the lateral angle and at the same time to prevent interference with external shocks.

Since there is often not much clearance between the lateral rod and the shock, interference is rare when the shock case diameter is large or when the shock is replaced with a separate tank type shock. Some down brackets not only lower the fixed part, but also offset it to the rear of the vehicle, thus increasing the clearance with the shock.

However, although the down bracket has the effect of correcting the left shift of the roll center to the center side, it also lowers the roll center and further distances the roll center from the center of gravity, resulting in an increase in the amount of roll. As a result, driving stability may deteriorate.

If interference with the shocks is not occurring and there is no reason to intentionally lower the roll center, an up bracket is recommended to raise the roll center and bring it closer to the center of gravity to reduce the amount of roll.

With 4x4 Engineering shock absorbers, there is no need to worry about interference with the lateral rods. Therefore, we have chosen to develop our products with up brackets for cornering performance.




  • Lateral up-bracket
    Item Number
    List price(Tax included)
    17,500yen (19,250yen)
    Steel 4.5mm, Up amount: 50mm, 70mm


  • ラテラルアップブラケット
    Item Number
    トヨタ・ランドクルーザー プラド GDJ150 / TRJ150
    トヨタ・FJクルーザー GSJ15W
    Price(Tax included)



  • Lateral up-bracket
    Item Number
    JB23 / 33 / 43 / 64 / 74
    List price(Tax included)
    8,800yen (9,680yen)
    Steel 4.5mm, 40mm up