By Jacob Hurd
The TeraFlex springs overcome the spring dropout by using spring isolators. These are built in to our bump stop in the front, and spacer in the rear, as well as spring retainer clips; so basically two ways to skin a cat. Many believe the multi rate and dual rate springs help prevent spring "sag." This is not correct. All springs will "sag" with weight added to the Jeep, which is actually just compression.
We Jeepers have a terrible habit of adding weight to the Jeep. Yeah that toolbox you added might not weigh a ton, and neither does that CB, or that new sub-woofer but they start to add up quick. For this reason we actually add built-in lift to our springs to compensate for this. For example, our 2.5" kit sits about 3”, our 3" kit sits about 4” and so on. We build in this additional height so that you still get the lift you paid for after accessories.
Now, you might think to yourself, “Man I'm getting 4 inches I'm going to have to get drive shafts.” Not necessarily. We have already accounted for the added height in our drive shaft and exhaust spacer recommendations. So, yes your lift will squat down a little after you add that bumper, but that is only because we gave you bonus height that you got used to and want it back.
While spring failure/sag does occur, it is rare. A majority of the springs we bring in for testing due to reported sag tend to exceed specs, but we like those accessories and the weight it brings. I'm personally guilty of it too. :)