Radius rod


Radius rod

A radius rod (also called a radius arm or a torque arm) is a suspension member intended to control wheel motion in the longitudinal (fore-aft) plane. The link is connected (with a rubber or solid bushing) on one end to the wheel carrier or axle, on the other to the chassis or unibody of the vehicle.

Radius rods typically are mounted ahead of the wheel. In that position they resist dive under braking forces and wheel hop under acceleration.

Radius rods are customarily made of stamped steel or aluminum for lightness, as they are part of the vehicle's unsprung weight. Improvements in composite materials technology make possible plastic suspension links, although they are still uncommon.

Other suspension components can be made to act as radius rods under certain conditions. For example, the rear suspension of the original 1966 Oldsmobile Toronado used shock absorbers to connect the rear beam axle to the frame; these shocks controlled longitudinal wheel movement, but their damping action prevented the forces of those movements from being felt by the passengers.

On a vehicle with longitudinal leaf springs, such as a Hotchkiss drive suspension, the springs themselves provide some longitudinal wheel control. One or more torque arms may be added to provide supplementary wheel control, particularly for vehicles with strong torque such as drag racers. On some leaf spring-equipped vehicles, such as 1960s Chrysler Corporation cars, the springs are mounted so that a greater portion of the spring's length is forward of the wheels, improving wheel control on acceleration. A side effect of such positioning is that the shorter, aft portion of the springs may not be stiff enough to control wheel movement under braking forces, which can lead to pronounced wheel hop in hard stops.


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Look at other dictionaries:

  • radius rod — noun : a bar for preserving an invariable distance between two pieces of a mechanism and permitting one to move around the other as a fixed point * * * (in a feathering paddle wheel) any of the rods, meeting in a hub mounted eccentrically with… …   Useful english dictionary

  • radius rod — (in a feathering paddle wheel) any of the rods, meeting in a hub mounted eccentrically with the paddle wheel shaft, for feathering the paddles while in the water. See illus. under paddle wheel. [1855 60] * * * …   Universalium

  • radius rod — An additional suspension link in a beam axle layout providing fore and aft location of the axle …   Dictionary of automotive terms

  • rod — [1] A modified car. Also see street rod. [2] To drive a vehicle hard. [3] A connecting rod. [4] To clean out a radiator by passing a rod through the lines. See rodding the radiator. [5] A thin bar. See boxed rod brake rod connecting rod con rod …   Dictionary of automotive terms

  • radius bar — noun : radius rod …   Useful english dictionary

  • Radius — Ra di*us (r[=a] d[i^]*[u^]s), n.; pl. L. {Radii} (r[=a] d[i^]*[imac]); E. {Radiuses} (r[=a] d[i^]*[u^]s*[e^]z). [L., a staff, rod, spoke of a wheel, radius, ray. See {Ray} a divergent line.] 1. (Geom.) A right line drawn or extending from the… …   The Collaborative International Dictionary of English

  • Radius bar — Radius Ra di*us (r[=a] d[i^]*[u^]s), n.; pl. L. {Radii} (r[=a] d[i^]*[imac]); E. {Radiuses} (r[=a] d[i^]*[u^]s*[e^]z). [L., a staff, rod, spoke of a wheel, radius, ray. See {Ray} a divergent line.] 1. (Geom.) A right line drawn or extending from… …   The Collaborative International Dictionary of English

  • Radius of curvature — Radius Ra di*us (r[=a] d[i^]*[u^]s), n.; pl. L. {Radii} (r[=a] d[i^]*[imac]); E. {Radiuses} (r[=a] d[i^]*[u^]s*[e^]z). [L., a staff, rod, spoke of a wheel, radius, ray. See {Ray} a divergent line.] 1. (Geom.) A right line drawn or extending from… …   The Collaborative International Dictionary of English

  • radius — [rā′dē əs] n. pl. radii [rā′dēī΄] or radiuses [L, rod, spoke (of a wheel), hence radius, ray (of light), ? akin to radix,ROOT1] 1. a raylike or radial part, as a spoke of a wheel 2. a) any straight line extending from the center to the periphery… …   English World dictionary

  • radius — /ray dee euhs/, n., pl. radii / dee uy /, radiuses. 1. a straight line extending from the center of a circle or sphere to the circumference or surface: The radius of a circle is half the diameter. 2. the length of such a line. 3. any radial or… …   Universalium


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