Rack End

The Rack End (Inner Tie Rod / axial rod ) is a crucial component of the automobile steering system, connecting the steering gear and the Tie Rod End (Outer Tie Rod). Its primary function is to transfer the motion of the steering gear to the steering arm, thus achieving vehicle steering. The composition and functions of the Rack End are as follows:

Functions of the Rack End

Transfer Motion: It transfers the rotational motion of the steering gear to the Tie Rod End, thereby changing the direction of the wheels.
Adjust Toe Angle: The threaded part of the Rack End can be rotated to adjust the toe angle of the wheels, ensuring vehicle stability and straight-line driving capability.
Absorb Impact: During vehicle operation, the Rack End needs to absorb impacts from the road, maintaining the stability of the steering system.
The quality and design of the Rack End have a direct impact on the vehicle’s steering performance and safety. Therefore, selecting a high-quality Rack End is essential for maintaining vehicle stability and safety.

Composition of the Rack End

• Housing:

  Usually made of high-strength metal, such as steel or alloy steel, to withstand the forces during steering.

• Ball Rod:

  One end of the Rack End typically features a Ball Rod, installed at the steering gear end, allowing free rotation at different angles to ensure the flexibility and safety of tire operation.

• Parts Bearing:

  Located between the Housing and the Ball Rod, it acts as a buffer sleeve to reduce wear at the Ball Rod during vehicle operation.

Testing Standards for OEM Rack End

OEM Rack Ends are subjected to a series of stringent technical standards and testing requirements to ensure their performance and durability under various conditions. Great Auto Parts’ Rack Ends undergo the following tests:

• Pull-out Test:

  The Rack End must have sufficient tensile strength to withstand various external forces in the steering system. Great Auto Parts’ Rack Ends can withstand an average pull force of 4 to 8 tons, exceeding the OEM standard of 3.5 tons. The tensile strength of the Rack End varies according to the ball head diameter and Housing thickness. Great Auto Parts sets inspection standards based on different part specifications. For passenger cars, the average pull-out strength is 4 to 6 tons, while 8 tons is suitable for heavy commercial vehicles.

  Great Auto Parts’ Rack Ends Ball Stud Pull-out Test and Qualification conditions

  		Ball Size(mm)
  		≦24	φ25	φ28	φ30	φ32	≧φ34
  Pull-out force	(KN)	≧25	≧30	≧35	≧40	≧45	≧50
  	(kg.f)	≧2550	≧3060	≧3570	≧4080	≧4590	≧5100

  

• GAP Test:

  The fit between the Housing and Ball Rod is critical. The smaller the clearance after assembly, the lower the wear rate of the Rack End ball head during vehicle operation, thus extending product durability. Great Auto Parts’ Rack Ends have a clearance of only 0.06mm between the Housing and ball joint after withstanding a pull force of 460kg. Even when the vehicle operates under harsh conditions, Great Auto Parts’ Rack Ends can maintain vehicle stability, and the excellent product durability reduces the likelihood of steering gear failure due to a loose Rack End ball head.

  Great Auto Parts’ Rack Ends GAP testing Test and Qualification conditions

  Ball Diameter	<25mm	25~34mm	>34mm	Unit
  F1 (Force)	±2,500	±4,500	±6,000	N
  SR (GAP)	0.15	0.20	0.25	mm

  

• Torque Test:

  The connection parts of the Rack End must meet specific torque requirements to ensure the solidity and stability of the connection. Great Auto Parts specifies the qualified torque range to be tested with a torque wrench for their Rack Ends.

  Great Auto Parts’ Rack End Rotational torque Test and Qualification conditions

  		Ball Size(mm)
  		≦24	25	28	30	32	≧34
  Rotational	(Nm)	0.6 – 5.0	0.8 – 7	1.0 – 7	1.0 – 8	1.0 – 9	2.0-13
  	(kgf.cm)	6.1 – 51	8.1 – 71	10 – 70	10 – 80	10 – 90	20-130

In addition to rigorous testing, Great Auto Parts’ Rack Ends are meticulously designed to meet the needs of automotive manufacturers and repair shops. Our Rack Ends feature heat-treated ball head bolts, offering unparalleled strength. These bolts bend upon impact to avoid breaking and ensure driving safety.

Safety is not our only focus—innovation complements it. Our Rack Ends comply with stringent safety standards while enhancing vehicle performance. Whether you are pursuing improved performance, safety, or environmental friendliness, our Rack Ends can meet your goals. Contact us to explore our product range and revitalize your vehicle’s driving dynamics!