WD Bars: How Do You Lift Them????

[mstephens]

Originally Posted by Ron Gratz

Can you tell us what WW measurements Andy said to shoot for?


Ron

His recent 300 was about 1/2" - 3/4" down in the front and 1/2" - 1" down in rear.

My current setup is 1/2" down in front, and 1-1/2" down in rear, BUT the rear was around 1/2" higher than stock due to the air shocks. The have to be a little extended in order to work on my car (there was no standard part for this car and it was installed as a custom install.).

So, I think my setup is now very much like Andy's. I'll visit the scale again.

[mstephens]

Originally Posted by Ron Gratz

I would agree if all of the 2500# on the front axle resulted from the mass of the tow vehicle and the location of its center of gravity.
However, about 25% of that 2500# is not a result of TV mass and CG location.

The 625# which was exerted on the front axle via application of WD is not a result of additional TV mass.
That 625# is a result of torque from the WDH being translated to a downward force on the front axle via leverage.

The extra 625# of tire load means additional lateral tire force, but there is no corresponding TV mass to absorb the effects of the additional force.
This causes the TV to "steer" more than the steering wheel angle is requesting.

There is delicate balance among front axle lateral force, rear axle lateral force, and CG location.
The imposition of a force, without corresponding mass, on the front axle can upset the balance.

Ron

It took me a bit to visualize this. But I think I see the difference. My intuition tells me that when there is no WD, the ball/coupler is sagging a lot. The initial WD easily lifts the back end to the point of about 20" above ground - the height ball started out. But as you try to apply more WD than that, it becomes very hard to raise the ball/coupler above 20" and the force applied begins to be just torque on the front axle. I think that's what is being said.