A Panhard rod (also called Panhard bar, track bar, or track rod) is a
suspension link that provides lateral location of the
axle
An axle or axletree is a central shaft for a rotation, rotating wheel and axle, wheel or gear. On wheeled vehicles, the axle may be fixed to the wheels, rotating with them, or fixed to the vehicle, with the wheels rotating around the axle. In ...
. Invented by the
Panhard
Panhard was a French motor vehicle manufacturer that began as one of the first makers of automobiles. It was a manufacturer of light tactical and military vehicles. Its final incarnation, now owned by Renault Trucks#Military vehicles, Re ...
automobile company of France in the early twentieth century, this device has been widely used ever since.
Overview
The purpose of automobile suspension is to let the wheels move vertically with respect to the body, while preventing movement forward and backwards (longitudinally), or side to side (laterally).
The Panhard rod is a simple device designed to prevent lateral movement.
RPM Net Tech Articles: Understanding Coil Springs - Powered by: AFCO
It consists of a rigid bar running sideways in the same plane as the axle, connecting one end of the axle to the car body or chassis
A chassis (, ; plural ''chassis'' from French châssis ) is the load-bearing framework of a manufactured object, which structurally supports the object in its construction and function. An example of a chassis is a vehicle frame, the underpart ...
on the opposite side of the vehicle. The bar attaches on either end with pivots that let it swivel upwards and downwards only, limiting the axle's movement to the vertical plane. This does not effectively locate the axle longitudinally, therefore it is usually used in conjunction with trailing arms that stabilize the axle in the longitudinal direction.
A Panhard rod is typically used with coil spring suspensions; with a leaf spring
A leaf spring is a simple form of spring (device), spring commonly used for suspension (vehicle), suspension in wheeled vehicles. Originally called a ''laminated'' or ''carriage spring'', and sometimes referred to as a semi-elliptical spring, e ...
suspension, the springs themselves usually supply enough lateral rigidity. However, Ford used a similar connected ''rear axle damper'' (fifth shock) on some Explorers and light trucks with rear leaf springs. Jaguar also used a Panhard rod to locate the rear axle on its unusual cantilever leaf sprung Mark 2.
Advantages and disadvantages
The advantage of the Panhard rod is its simplicity. Its major disadvantage is that the body must necessarily move in an arc relative to the axle, with the radius equal to the length of the Panhard rod. If the rod is too short, it allows excessive sideways movement between the axle and the body at the ends of the spring travel. Therefore, the Panhard rod is less desirable on smaller cars than larger ones.
Two notable exceptions to this are the Mitsubishi Pajero Mini and Suzuki Jimny. Both are small light vehicles (they fall in the light vehicles category in Japan) that have a Panhard rod, but the off-road nature of these vehicles means that the lateral movement between axle and body is not important. A suspension design that is similar but dramatically reduces the sideways component of the axle's vertical travel is a Watt's linkage.
Applications
Some vehicles with live-axle suspensions cannot use a Watt's linkage due to design or other practical constraints; these often incorporate a Panhard rod as a component of the front suspension. The Mercedes-Benz G-Class
The Mercedes-Benz G-Class, colloquially known as the G-Wagon or G-Wagen (as an abbreviation of Geländewagen), is a four-wheel drive luxury SUV manufactured by Magna Steyr (formerly Steyr-Daimler-Puch) in Graz, Styria, Austria, and sold by Mercede ...
was redesigned in 2018 to include a Panhard rod on the rear axle to improve its on-road handling characteristics.
See also
* List of auto parts
This is a list of auto parts, which are manufactured components of automobiles. This list reflects both fossil-fueled cars (using internal combustion engine
An internal combustion engine (ICE or IC engine) is a heat engine in which the c ...
* Scott Russell linkage
A Scott Russell linkage is a linkage which translates linear motion through a right angle.
The linkage is named after John Scott Russell (1808–1882), although watchmaker William Freemantle had already patented it in 1803.
A different form of ...
References
{{Chassis control systems
Automotive suspension technologies
Linkages (mechanical)
Panhard