[Skypalace]

Ok, you opened this can of worms so here they are.

In my not so humble opinion………..there is a difference between the toe in set on an alignment rack and the toe in measured as the coach rolls down the road.

I have used the toe in of 1/16 as it rolls down the road for the last four years. If you find all my posts on the front end fixes and adjustments you will see that I am OCD about how the coach drives. I do not have ‘wander’ in the steering. I do have a slight toed in wear pattern in the tread, and there is about 50k miles on the steer tires. I run tire pressures AT the recommended inflation pressure for the front axle weight, not 5 or 10 psig above.

Very few people are going to go to the trouble of making a trammel bar and rolling the coach 20 ft forward to check the toe. And certainly trying to get a tech using an alignment rack to take it off the rack and do it that way is a no go. So setting the toe to 1/8 to 3/32 on the rack allows for a wee bit of movement to result in something closer to 1/16 on the road. It’s hard to speculate on how much difference because each coach will have a different amount of play in all the joints.

I will comment on one other thing. You should not have any toe out. The least bit of toe out will result in a coach that unpredictably darts from side to side. If you have that situation, it is not relaxing to drive at all.

And one more thing about the DANA IFS 84 front end is that it is insanely sensitive to ride height when setting the toe. It must be at the travel ride height when setting the toe. That can only be achieved by lowering the coach below ride height and putting it back into travel mode. This minimizes the hysterisis in the ride height control valve. I have demonstrated for my self that a 1/2 inch difference in ride height translates into a 1/4 inch difference in toe. It is all related to the hypersensitivity of the HCV mounted to the sway bar combined with a trigonometry change given one end of the tie rod is fixed to the frame and one end is fixed to the a arm. A difference in ride height changes the angle of the tie rod arm thereby changing the tie rod effective length.

Sorry for the dissertation, too much coffee and rain this morning.

All great info, thanks! I'm an engineer so the more info and data and understanding about how things work, the better.

I'll give Kaiser Brake & Alignment in Eugene a call and ask how they set both toe and ride height on the rack, I think repairs finished today and alignment tomorrow so great timing.

Great to learn. I race cars competitively and front end is the opposite, I need a little toe out in the front or the front end is very 'happy' with even small bits of lateral weight transfer, so get wandering w toe in and less overall frontend grip in corners. It sounds counter-intuitive, but when cornering at the limit you've always got slip and dealing with differential slip angles, plus of course constant geometry changes under the high longitudinal and lateral loads. The rear is the opposite, need a hair of toe in to keep things stable on the straights, and the squat under acceleration will cause dynamic toe out effect so I'll get effective zero toe (and thus no scrub) under acceleration out of corners.