AVTekk
+1y
Your conception of weight is a little off man, but no worries, this is how it works... Any type of spring has a measurement of force needed to compress it, called spring rate. Airbags are no different, except for that fact that you can primarily change the spring rate with air pressure. For this discussion, the typical rule is the stiffer the spring, the more weight it can handle. This rule isnt the end-all rule because many manufacturers have dual rate steel springs with tighter windings that give a softer ride with normal driving but stiffer on large bumps to prevent bottoming out. Anyway, back on topic, since weight capacity is generally a direct result of the spring rate, we can deduce that a bag rated at a higher capacity will ride worse, at the same weight load, at the same pressure. A F9000 has a capacity of 1500lbs ea, the RE7s you swapped them with are rated at 3000lbs ea, so theyre going to ride worse unless you either add more volume (accumulators) or add more weight (a lot more weight). Why you swapped them out I dont understand because F9000s ride great and get 7.5" of lift...The design of the bags (tapered vs double convoluted) and the material theyre made from also give different rates, same thing for the shape and type of metal spring windings as well. I mentioned volume for a second because it makes a big difference in air springs as well. You don't see any RE6s over axle because they have less volume, causing them to operate at higher pressures and a stiffer rate. They also don't get as much lift, so to get to your specified ride height, they are at a higher pressure, again riding worse. Now volume is where the tables turn a bit, because you ran go up to a RE8 and have a softer ride then a RE7 even though the RE8 is rated at a higher capacity. The reason this is true is because the RE8 has more volume and takes less pressure to reach the same ride height.Now when you put bags into a leverage setup, youre basically showing the bag more load then whats actually there, so its operating as if there is more weight on it. Since the bag is now seeing more load, its capacity is also greatly reduced by the same amount of leverage placed on it. So if the bag is directly in the middle of the bar, its on a 2:1 ratio, and its capacity is cut if half. This is an important factor is designing a suspension because if you put too small of a bag in a lever situation on too large of a truck, they will fail.