Frequently Asked Questions
Additional information to create clarity.
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While holding the tie rod with the ball joint at the floor, if the direction of the thread is going up and to the left the thread is left handed, and if it is going up and to the right it is right handed.
Depending on the vendor, there may be an L or R stamped on the ball portion of the tie rod end.
Self Steer & SMART-STEER
Yes.
The kin pins are stamped LH and RH on the top of the king pin opposite the rotation hole.
Yes, the parts are interchangeable.
We recommend using an expansion tank of 1,000-1,500 inches per steer axle when using a Torpress style self-steer. This is based on a normal operating Torpress air spring pressure of 30-40 psi for rear facing tie-rod models or 75-80 psi for forward facing tie-rod models.
If an expansion tank is not used, the starting (at rest/centered) position of the Torpress air spring must be set to approximately 15 psi so that when the pressure increases in the air spring, it won't be too high and will still allow for the axle to turn properly. By not using an expansion tank, the air spring will not have enough pressure to center the wheels immediately after a turn and the wheels will "wobble" as they return to a center position and will therefore "scrub" against the road and increase tire wear.
If an expansion tank is not used, the starting (at rest/centered) position of the Torpress air spring must be set to approximately 15 psi so that when the pressure increases in the air spring, it won't be too high and will still allow for the axle to turn properly. By not using an expansion tank, the air spring will not have enough pressure to center the wheels immediately after a turn and the wheels will "wobble" as they return to a center position and will therefore "scrub" against the road and increase tire wear.
Full spring brake chambers are not usually necessary, but you should confirm this with the regulations in which your trailer is operating. In general, as long as your trailer can pass the parking brake test requirements without spring brake chambers, you are fine to operate without them.
When Packaged:
Red sleeve over the threads is a right hand thread; yellow thread over the sleeves is a left hand thread.
While holding the tie rod with the ball joint at the floor, if the direction of the thread is going up and to the left the thread is left handed, and if it is going up and to the right it is right handed.
Depending on the vendor, there may be an L or R stamped on the ball portion of the tie rod end.
On rear facing tie rod models, we would expect to see between 30 and 40 psi. On forward facing tie rod models, we would expect to see between 75 and 80 psi.
Vertical play is not important with the self-steer axles as long as the O-ring is keeping the grease inside. On a brand new axle however, the vertical play should be roughly 1/16" and when worn, could be as much as 3/16".
If a vertical play becomes a concern, shims are available for purchase to reduce this movement. They come in 0.015" and 0.030" thicknesses with part numbers 700703 & 700702 respectively.
The allowable limits for caster angle are 0º to +3º at ride height. Improper caster angle can lead to reduced turning performance and premature tire wear. See the troubleshooting section to understand the elements that effect castor angle.
During straight line operation, the Torpress dampens the shimmying (the shopping cart effect) of the axle. During maneuvering, the Torpress helps return the axle to center. The Torpress also keeps the axle centered when the axle is in the raise position.
A leading king pin self-steer axle is where the pivot point of the axle is in front of the axle tube. This allows the axle to steer passively through road friction. Otherwise known as Dexter's SMART-STEER.
An inline king pin is where the pivot point of the axle (the king pin), is inline with the axle tube. This type of axle is typically found in forced steer applications.
Caster angle is the vertical offset angle between the king pin axis and the road.
This air spring is part of the Torpress assembly and is called the Torpress air spring.
Per IN035, self-steering axle king pin and bushing wear inspection; 0.031" side play movement is the maximum allowed. if the movement is more than that, then the king pin and bushings should be replaced.
Toe in and toe out is the angle the tires make with the frame of the trailer in the direction of travel:
- Toe in (positive toe) is when the tire is pointing towards the frame
- Toe out (negative toe) is when the tire is pointing away from the frame
- Toe in and toe out are set when the axle leaves the factory. Otherwise follow procedure IN020 to check your toe in/toe out setup
Dexter offers standard turn angles of 15, 20, 25, 28 and 30 degrees but we can customize to whatever turn degree you require.
Yes as long as its not a tapered style king pin. If you have an older style, it can be identified by the single screw lock instead of the two draw key set-up as used in current production self-steering axles.