previous owner installed the Timbrens probably because of sagging leaf springs but with a full tank of fuel there is no gap between stops. rides rough. what is the most economical alternative?
shackle lift?
Re-arch springs?
New Spring pack or...?

 

does the truck sit level? are the springs flat, at the negative arch point?

 

Sits level. Still has some arch. cannot seem to post a pic with Android?

 

see if this works...
Truck has 1/4 tank fuel in Pic. right side Timbren has three quarter inch clearance, left side has no clearance.

 

I seem to remember reading that the timbrens are supposed to be setup tight like that? check out the load rating for the set that you have, on the timbren website.

one thing you could try would be to pull 'em out, check the ride, and see how it bottoms out without 'em.

that would tell you if the spring pack needs reinforcing... those springs look kinda flat to me, and i'm wondering if the shackle angle says anything about how much spring capability is left on 'em.

 

I've talked to Timbren, said I should have .5 to 1.5" clearance between rubber and stop. recommend I purchase a set of 2.75 inch rubber Springs. truck now has 3.5 inch Springs installed.
yes I would like to learn more about the shackle angle and how to measure.

 

Those springs look fine to me. Take them stupid things out of there. They're obviously not doing you any good anyway. Sounds like they're the entire cause of the problem to me. And for pete's sake, don't buy another set. What kind of sense would that make?

Shackle angle? Is going to tell you what exactly? How? As in you're going to compare the angle measurement to what to learn what about what? Yeah...I don't think so. Don't waste your time.

BTW, it's a truck. Don't expect that much of a change. Regardless of what you do.

 

what you'd need to make it relevant to your situation would be shackle angle measurements from a stock Toyota pickup, using one of those cheap protractors.

my 4runner is very heavily modified, and even with all of the spring arch in back, the shackle angle is 67 degrees, not as sharp an angle as yours... apples and oranges, tho.

in general, as the spring wears out and flattens, it's longer at normal ride height, which changes the shackle angle.

here is the theory behind it, fwiw... you are already thinking about working on the springs, maybe a trip to the junkyard is in order?

"Shackle Mechanics

The angle of the shackle can stiffen or soften a spring's normal rate. You can determine the effective angle of a shackle by drawing a line through the middle of both spring eyes and a line through the shackle pivots. Then measure the angle formed by the two lines (measure ahead of the shackle - see illus. 3). You can increase the effective rate of a leaf spring by decreasing the shackle angle. An increase in shackle angle will produce a decrease in the effective leaf spring rate of a leaf spring.
A good starting point for shackle angle is 90 degrees. In this position the shackle has no effect on spring rate. Keep in mind that the shackle angle changes (and consequently the spring's effective rate changes) whenever the suspension moves. Also, the shackle's angle will change whenever you change the chassis' ride height, the arch of the leaf, the load on the leaf, or the length of the shackle. Since the shackle direction changes when the leaf is deflected past a flat condition, you should avoid deflecting the right rear leaf to an extremely negative arch condition. This could cause a very large shackle angle at high loads and consequently a very soft spring rate. Excessive body roll and poor handling could result. You can correct this problem by decreasing the shackle angle, increasing the arch, of the spring by increasing the rate of the right rear leaf spring."
http://www.quadratec.com/jeep_knowle...article-93.htm