Greg,
When you went to install the shocks did you loosen the rear shackle bolts? Remember they run a rubber bushing on the shackle so you will need to pull down when they are still in the torqued down position if you didn't loosen the bolts. When the truck is moving and going through it's normal paces the forces of the rear-end pull the spring down forward just as you had to do when installing the springs giving you full droop. Rubber shackle bushings are far different than Poly bushings and will not simply droop out all the way just by raising the rear of the truck on a lift. Rubber only droops all the way when there is actual momentum in the rear as seen in real world conditions.
The Standard Duties started out lower in the rear when we first started doing them because the majority of people asking us about them and wanted the ride height in the rear to be a bit lower. Then we started to get more requests for stock ride height so we now build them more to order vs just sending them out at a pre set height.
I believe Cody's Truck and the other one is a SCAB, and about 250 pounds lighter. This would make sense why your's would be sitting lower in the back. Standard duty springs are a lighter rate then stock and are very sensitive to extra weight. You can see different variances in ride height just base of the gas tank being full or not.
We have seen hundreds of these sets go out and have them on both SCABS and SCREWS local to us that are still running the same ride height as when they were installed. These trucks have all had many hard miles on them offroading plus including towing and heavy payloads. The only time we have ever seen a Standard Duty lower in the rear was when customers started adding more weight in the back with bed cages, dual tire setups, tool boxes and so on, but even then the springs weren't sacked out. We have yet to see a set lower from just from being on a truck that hasn't added any more weight to it. Like all springs they will take a set of about .5- .75inches when they wear in but shouldn't budge much from there if everything else stays the same. We have loaded up over 1500 pounds on many occasions for testing this exact thing and every time the payload was removed, they popped right back up to the normal ride height that was set from the start
Joe's picture shows how much less arch there was in the lower ride height springs. That pic is consistent with a set that was 1.5" lower in the rear vs a set that is stock ride height.
There has been some mis-information on this thread so I just want to make sure everyone knows the following:
1. Original sets were arched 1.5" lower and show very little arch when on the truck even right out of the box, they were designed that way to achieve the lower ass end ride height and is not a clue of a sacked out spring
2. They are very sensitive to weight and a SCREW will take a different set than will a SCAB.
3. This is very important. Rubber bushing behave much differently than what others are use to seeing with their Deavers that use poly bushings. When The back of the truck is raised via a lift or a jack, the lower arched Nationals like on Gregs truck will not fully droop because they are torqued down in a neutral or loaded position during install. When the truck is driving and going over bumps, jumps and whoops the rear WILL fully droop because of the forces applied by the momentum of the rear ends weight. This is just a characteristic of a torqued down rubber bushing. Your travel is the exact same, it just reacts differently during install and when jacked up on a lift.
4. We have seen more sets than anybody and have yet to have to replace the spring because of so called sagging. The only time we've replaced springs for customers was after they added more weight to the bed or requested more ride height. Not because the spring sagged. Joe's springs are a good example of this, his rear was lower than he liked so we re-arched them and all is good now.
5. Rearching. They are cold formed springs so it's very easy for us to take your current springs and re-arch them for more ride height if desired.
6. We are waiting on Greg to get us a ride height in the rear of the truck. If the ride height is measured from the ground to fender then we need to take into account the amount of wear from the tire tread loss as well as any additional weight that might have been added to the truck including current gas tank levels. I would also like to see if the spring is bowing around the axle. Until we get all this we cant say if his spring is sacked out or not.
Long story short, there are lots of variables that go into this and to date we have only seen one genuine sacked out spring and that was done on purpose by us to determine how far we could go with them until they yielded. We ended up killing the spring in one 2 hour session in the dirt. National uses all US or Canadian Steel that is very good in material properties. It takes a lot to kill one of them. But regardless, we need to get you a new set with a higher ride height so you can enjoy them before the Snoball.
I want my truck to sit completely level so not sure if I should mess with the ICON factory height setting or not. I think I will run RCV shafts when I get the new style cup.
