I am not considered mechanically inclined by any one I know but I do believe that cranking up torsion bars should be done cautiously. When I asked my dealer about cranking up mine on the Alpha which has 20" rims and 35" tires his advice was to install a front lift kit. When looking at my options I found an article on torsion bars andhave included some it herefor whatever value (figures wouldnot paste in) it mayhave in making a decision to crank up the bars or install a lift kit. I installed a lift kit.

Understanding Torsion Bar Suspension
A torsion bar suspension system uses the properties of elastic twisting action in a bar of steel to provide suspension. This method is popular on many trucks, because it provides for ample clearance for the front drive shafts and thus makes packaging of the front suspension much simpler on a four-wheel drive vehicle. It is important to remember that a torsion bar is simply a spring, just like a more conventional coil or leaf spring that you may be more used to seeing on a vehicle. Most torsion bar suspensions use an adjuster called a torsion key to facilitate installation and ride height adjustments.

Torsion keys are used to adjust the orientation of the torsion bar in relationship to the lower control arm of the suspension. This adjustment is necessary because unlike a coil spring, the initial ride height of a torsion bar equipped vehicle is not obvious. Also, the exact twist of a torsion spring can have a large effect on the ride height of a vehicle. In our testing, we have found as little as 3 degrees difference in twist can affect the ride by as much as one inch.

During driving, the load path of the front suspension of a torsion bar equipped truck passes through the tire, the spindle and the lower control arm, down the torsion bar, through the torsion key and down through the torsion key adjusting bolt and into the cross member of the frame. In other words, the entire load of the front of the vehicle is riding on the torsion key adjusting bolt. See figure 1 for a diagram of a torsion key and bolt
Figure 1 – Torsion Key at 0-degrees to adjusting bolt
Drawing supplied by General Motors
The amount of load carried by the front wheels varies from model to model, with the diesel powered trucks weighing more than their gas powered cousins. Other variables include the optional equipment that might be installed on the front of a vehicle, such as winches, large bumpers or snowplows. (It should be noted that any extra weight would only aggravate the load on the front suspension, as well as increase the rake of the truck at rest).

To calculate the actual load on the front suspension of a modern truck, we will make a few assumptions. Let us assume that our sample truck weighs 5000 lbs, and that 60% of the weight of the vehicle is on the front axle. The control arm has an average length of 20 inches to the center of the wheel and the torsion key has a length of approximately 5 inches. This gives us a ratio of 4:1 for the leverage between the control arm and the torsion key. In figure 2 we can see that this gives us a static load of 6000 lbs on the torsion key adjusting bolt.

FrontAxleLoad = 5000lbs x 60% - 3000lbs