Is this really true? I was thinking about it the other day.
Stock weight is about 5,500 lbs and I've heard that AHC handles half the weight while the springs and torsion bars handle the other half. So AHC would ideally always be handling about 2,700 lbs of weight.
If you load up the truck and it weighs 7,500 lbs, I get that you can put in springs and crank the torsion bars to the point where it "erases" the extra weight and AHC will still only need to handle about 2,700 lbs. But it sure seems like the force of a 7,500 lb truck coming down hard on the dampers would be different than the weight of a 5,500 lb truck in the same situation. Do the springs and torsion bars really erase that weight from the equation even under hard compression?
Right, I get that. I was using 7,500 as a ridiculous number to exaggerate the question.
Basically, does using springs to offset ANY amount of extra weight allow the AHC to operate normally if all it needs to suspend is the 2,700 lbs it's designed for?
For example, if you had a million pound vehicle that was appropriately designed and used springs to handle all but 2,700 lbs of its weight, could you use AHC to raise, lower, and dampen the suspension on that theoretical vehicle?
I suspect it would raise and lower just fine because AHC would literally be blind to the other 997,300 lbs. But when that thing hits a bump, it seems like the inertia generate more force on the AHC dampers even with the springs offsetting the static weight.
This is a good question and worth understanding.
The damping for AHC is variable. Both by the manual control knob in the cabin and by the AHC ECU.
One imperfect, but perhaps helpful, way to think of the damper knob in the cabin would be "weight". It's really firmness/damping along with anti-dive/roll, etc.., but if we assume the goal is to maintain a constant damping effect, we could consider the 4 settings to represent the amount of weight they dampen. Adding weight to the car? Your 4 setting with a lot of weight might now behave like 3 with factory weight. 3 might be 2. 2 might be 1. Crank the dial to the right and you've essentially increased the weight capacity for the dampers.
I'm sure you can overwhelm the damping range of the AHC dampers, but they have a pretty wide range of adjustability from the cabin control knob and then the ECU manages additional damping. Combine the two and that means you can add quite a bit of weight and maintain sufficient damping for combined use with almost no effort. With conventional shock setups the approach to dialing in damping generally involves using high-end variable shocks or swapping a multitude of shocks in and out. You might end up with a better final matched set than AHC, but it will cost quite a bit and require a significant amount of effort.
The AHC hi-lo thought process gets a little funky because spring rates matter. The pre-load determines the standing height, but the spring rate determines how easy/hard it is for AHC to lift the car from N. Lifting 2" above N is easier if you have high spring rate springs installed. It's very difficult if you have weak springs.
Anyways, lots of potential tangents here, but suffice to say:
AHC won't be the weak link when it comes to weight. Your knowledge of the system and how to adjust it might be a limitation, but the system itself is not a limitation within any sort of reasonable bounds. @kreiten is a great example of a built 100 with little regard for weight savings that remains immensely capable and I assume far more comfortable than any other vehicle that's running Rubicon.
My build was executed with some attention given to weight only in the sense that I opted for aluminum instead of steel where possible. At no point did I opt out of any mod in the name of weight savings.
(knock on wood
