Since the late sixties, I have tried many methods to keep the rear up or bring it back up close to stock. My conclusion and belief is only Air Bags will do the job. I have installed Air Bags on several of my trucks, and never have been disappointed with the result.
1) adding another leaf;
If you never unload your TC, like a Class A or Class C, adding a leaf or more will raise the rear. It is fixed and not adjustable. It will do the same on a truck with a TC, but you will have a much stiffer ride when you do not have the TC loaded. I think this should be obvious.
2) SuperSprings;
My understanding is they work on the same principal as Overload springs. I have no personal experience with the SuperSprings. I am comfortable with the thought they are progressive, meaning they have a fixed position, and as they are loaded they will squat but not as much as stock springs. Every overload spring device I have ever used or seen, has to squat until it takes the load. Regardless of method used to add a spacer or something related, it will squat. I agree it will squat less than without the spacer. I have yet to see a spring setup that allows you to load the truck, then bring it back to its original height. How anyone can argue against this really stumps me.
3) Timbrens or;
I have coil springs on the front of my truck. I installed Timbrens on the front of my truck. They look and act like bump stops, and actually replaced my bump stops. They are progressive in how they work. Typically, they are not engaged. When they are engaged, they become stiffer as they are compressed. My truck is 2WD, with less tire clearance in the wheel well. I installed 245x19.5 tires/wheels. On uneven ground under certain circumstances, I would have a tire rub the wheel well flange. Unless the Timbrens you are referring to are different than mine, they will allow the rear of your truck to squat, but not as much as stock.
4) Airbags;
I am sold on Air Bags for keeping the rear up. They also allow you to easily soften or stiffen the ride. You can use them to level you truck when camped. If inflated properly, they will not effect the empty truck. The only issue I have ever seen with air bags is improper install, or not used correctly.
My Air Bags have an In-cab controller. This allows me to adjust the air while in the truck, on the road or at a stop. Before the In-cab controller, I plumbed the bags separately to the inside of the truck, and used a small compressor while seated out of the elements. I don't care if it is raining, wind blowing or exceptionally hot outside. I do not have to get wet or muddy changing location of any adjustment device. I installed them used in 2005, and have never had a problem with them.
Wayne
