Spicer Steer Axles Application Guidelines - Manual (Page 44)

< 38 > back AXAG400 – February 2007
Steering knuckle – the inner portion of the spindle that is connected to and pivots on the kingpin allowing
the wheels to turn while under load.
Stop screw – a combination screw and lock nut arrangement that limits the angular travel of the steer
knuckle in a steer axle.
Tag axle – a "dead axle" (no driving capability) used to give vehicle more weight carrying capacity. A tag
axle is behind the drive axle. This type of axle may have the capability of being raised or lowered and
some are made to be “steerable”.
Taper – cone shaped object or form.
Thrust bearing – these bearings are designed to carry only thrust loads.
Tie rod arm – the arm that is rigidly connected to the steer knuckle that ties the LH knuckle to the RH
knuckle and also sets up the steering/Ackermann geometry.
Tie rod arm angle – the angle formed in the horizontal plane between the vertical plane formed by the
kingpin intersection/pivot point and the tie rod arm mounting hole where the tie rod end attaches.
Tie rod end – threaded part with a ball socket for articulation which attaches in the cross tube for
adjustment; each end is threaded the opposite of the other.
Tie rod offset – the distance from the kingpin intersection/pivot point to the tie rod arm mounting hole
where the tie rod end attaches in the lateral direction.
Tire pressure controls – see CTIS.
Toe – the difference between the tire centerline-to-centerline distances in the front versus the rear.
Toe-in – positive toe; tires are pointing in as seen from the front; provides straight-line directional stability.
Toe-out – negative toe; tires are pointing out as seen from the front; will result in “road wander”.
Track – distance between the centers of the tires.
Tubular beam – beam constructed of a seamless / hollow tube with forged steel beam ends welded on
the ends to create the foundation of a steer axle.
Turnpike – expressway or freeway.
Unitized hub system – hub system that is factory filled with synthetic grease and sealed to avoid
lubrication intervals, bearing adjustment, and seal replacement, eliminating hours of typical
maintenance.
Wheelbase – distance between centerline of front to rear axles or to centerline of tandem axle.
Wide track – axle that is wider than standard maximum 96” overall width.
Woodruff key – a half-moon shaped piece of metal used to secure something to a shaft which has a
notch cut in the shaft to accommodate the key.
Zerk – grease fittings; lubrication fitting used for pressurized grease application