Originally posted by 94ED_Fairmont
...Now I need help understanding some jargon:
1. What is Front setback?
2. What is S.A.I.and Included Angle?
3. Thrust angle? On the rear I think.
4. What is castor?
I know toe and camber. Not sure about the others.
I'll have a guess but if anyone knows for sure please correct me.
1) Front setback - I reckon your RH front wheel is setback slightly further in the wheelwell than the left.
2) SAI - Steering Axis Inclination. This is the designed in offset between the upper and lower balljoints when viewed from straight ahead at zero camber. An imaginary line drawn between the balljoints should intersect the road close to the centre of the tyre. Included angle means the end result after camber is taken into consideration.
(Included Angle = SAI + Camber)
(eg IA = +6.30 = +7.30 -1.00)
3) Thrust angle - I think this is telling you that the rear axle isn't pushing 100% down the centreline of the car but is slightly offset. Note how the right rear has +ve toe and the left rear has -ve toe, this means the axle is slightly offset to the cars centreline.
4) Castor is the angle (compared to vertical) of another imaginary line drawn between the balljoints, this time viewed side on. The rear balljoint should be slightly behind (more rearward) the front balljoint. This helps the steering to return to centre after turning and provides a more stable straight ahead feel.
It's interesting that you have some negative camber on the rears with a live axle. Just like the V8Supercars!