Broncobowsher
Total hack
- Joined
- Jun 4, 2002
- Messages
- 35,124
if it darts to the right when braking and goes to the left during acceleration, its the geometry of the radius arms. the radius arms both point outward, this makes the axle only straight or perpendicular to the frame rails at on exact point. having steep angles makes it more noticeable due to more side to side movement. picture your suspension as if you were looking down on your rig looking through the hood, youll see that as the axle moves to one side or another the axle actually turns, because one radius arm becomes more straight and the other more angled.
ther is nothing you can do about this except build radius arms that are parallel with the frame rails.
this is similar to what people refer to as lean steer with a 4link.
I dont think it is so much the radius arms but the track bar. When they start getting steep like the one pictured earlier they start sweeping side to side turing the vertical movment.
Picture the minute hand on a clock, at :45 it is level. The tip has almost no side to side movment as it sweeps from :43 to :47.
But at :38 it is at an angle. Do the same sweep, :36 to :40 and you have noticable side to side movment of the tip while less vertical travel then at :45. So at steep track bar angles, the axle has laterial movment diring suspension cycling. Now hopefully the drag link has matching geometery or else they will be fighting each other making a coumpound problem, thus the reason you fix steering geometery and track bar geometery at the same time.