Shackle flip travel question…

[Stephen]

Just turning the flip around to run 56s is going to make the shackle angle pretty steep and will likely limit your compression travel. With a steep shackle angle (like the internet ordained magical 45 degree) the spring won't compress past flat and with stock or low lift springs that can cost you some valuable travel. I've felt it as a ride quality problem too as travel stops pretty abruptly when the spring hits the flat position. You should really shoot for more like 20 degrees back when the spring is flat. This is measured with lines between the spring eye bolts and the shackle eye bolts, not compared to the ground, vehicle or level.
And as for the original question, you can get a guesstimate of shock travel based on full droop and ride height positions (which are easy to hit) along with a little measuring and imagining for the bump side of the equation. A good tool can be a set of shocks you may already have with a zip tie on the shaft that will push up and show you how far they're compressing.

 

[1-ton]

Just turning the flip around to run 56s is going to make the shackle angle pretty steep and will likely limit your compression travel. With a steep shackle angle (like the internet ordained magical 45 degree) the spring won't compress past flat and with stock or low lift springs that can cost you some valuable travel. I've felt it as a ride quality problem too as travel stops pretty abruptly when the spring hits the flat position. You should really shoot for more like 20 degrees back when the spring is flat. This is measured with lines between the spring eye bolts and the shackle eye bolts, not compared to the ground, vehicle or level.
And as for the original question, you can get a guesstimate of shock travel based on full droop and ride height positions (which are easy to hit) along with a little measuring and imagining for the bump side of the equation. A good tool can be a set of shocks you may already have with a zip tie on the shaft that will push up and show you how far they're compressing.

All I did was go for an equal amount of compression and rebound travel on the shocks I bought from you. Ten inches of travel is the longest travel available with the Bilstein 1500 series shock according to the Bilstien shock chart. I had to cut the original shock mounts off of my 14-bolt. I welded a set of mounting tabs I bought from you to the top of my 14-bolt axle tube, in order to make the rear shocks I work. I have limiting straps set at about 3" because I do not want my shocks to become limiting straps if I hang a tire while off camber. That could break a shock on a truck with heavy 1-ton running gear.

 

[Blue85]

All I did was go for an equal amount of compression and rebound travel on the shocks I bought from you. Ten inches of travel is the longest travel available with the Bilstein 1500 series shock according to the Bilstien shock chart. I had to cut the original shock mounts off of my 14-bolt. I welded a set of mounting tabs I bought from you to the top of my 14-bolt axle tube, in order to make the rear shocks I work. I have limiting straps set at about 3" because I do not want my shocks to become limiting straps if I hang a tire while off camber. That could break a shock on a truck with heavy 1-ton running gear.

Ah, so it is just dividing by 2. Your other post made it sound like you had done droop/stuff measurements. I don't think there is a 1500, so you likely meant 5100. 10" travel is the shortest one ORD lists for lifted trucks https://www.offroaddesign.com/catalog/product/view/id/1675/s/bilstein-shocks-for-67-91-gm-trucks/. They still have the 12" and the 14", like they always have. Moving the shock tabs up so high is what put you in such a short shock.

 

[nutt7]

Just turning the flip around to run 56s is going to make the shackle angle pretty steep and will likely limit your compression travel. With a steep shackle angle (like the internet ordained magical 45 degree) the spring won't compress past flat and with stock or low lift springs that can cost you some valuable travel. I've felt it as a ride quality problem too as travel stops pretty abruptly when the spring hits the flat position. You should really shoot for more like 20 degrees back when the spring is flat. This is measured with lines between the spring eye bolts and the shackle eye bolts, not compared to the ground, vehicle or level.
And as for the original question, you can get a guesstimate of shock travel based on full droop and ride height positions (which are easy to hit) along with a little measuring and imagining for the bump side of the equation. A good tool can be a set of shocks you may already have with a zip tie on the shaft that will push up and show you how far they're compressing.

I have this problem of over measuring and excessive planning so it’ll be sure to get mounted in an ideal position. With the 4.5” shackle, the lowest angle formed by the shackle and the top leaf is 36 degrees before contacting the leaf, when completely fIat. I plan to start here, basing it off the springs ability to go flat and beyond and seeing how it goes from there

 

[nutt7]

Well I’m kind of an idiot. I thought forever that I had 52s. I don’t. I even ordered my old RC lift correctly (in 2007 or so) so…who knows why I had that idea. I have 56s. So that makes mounting easier. The math I calculated was within 1/8” of where ORD places the hanger eye. I loosely hung it all and it’ll sit about where it’s supposed to be. Next I’ll disassemble the pack and hang the main spring to get an idea of flex etc. Still perch moving and lots of painting and which is always a time killer.

On another note, I learned why I think the old springs had a sag on one side…the shackle is locked in place on the spring in a slight compression. Any “flex” was the bushing twisting. It took some force with a pry bar to get it to finally budge and pop