Flip rear leaf spring hanger for extra lift?
- Thread starter bazar01
- Start date
Spring length = 59 inches
Mid point = 29.5 inches
Lift at hanger = 3 inches
Lift at midpoint = 1.5 inches
I will get a 1.5 inch lift at the axle just by flipping the spring hanger.
Hanger will be subjected to compression instead of tension loading.
I might do it pending some more investigation in a few weeks.
Any comments?
Mid point = 29.5 inches
Lift at hanger = 3 inches
Lift at midpoint = 1.5 inches
I will get a 1.5 inch lift at the axle just by flipping the spring hanger.
Hanger will be subjected to compression instead of tension loading.
I might do it pending some more investigation in a few weeks.
Any comments?
Cheyenne
UK 2004 T1N 313CDi
This exact same question was asked recently, maybe a month or two ago. Try the search or if I can find it I will post a link.
Here you go... https://sprinter-source.com/forums/index.php?threads/107058/
Here you go... https://sprinter-source.com/forums/index.php?threads/107058/
Last edited:
OrioN
2008 2500 170" EXT
Just use the lift spacer, I did.
Then I have to buy 2 spacers and 4 longer u-bolts.
This is free just sweat needed.
OrioN
2008 2500 170" EXT
You don't need to extend the shock, if the goal is to get the ride height back to unleavened stock height.
Shackle flip lifts are common in the 4X4 community. Catch is to have a shackle that is strong under compression, when the original design was to be strong under tension. Other thing to note is that doing a shackle flip alters your pinion angle on your rear driveshaft.
If you spring is 59" eyelet to eyelet it would alter your pinion angle 1 degree for every inch the rear of the spring is moved down. (59" radius, 118" diameter times PI = 370.52" circumference. 365 degrees in circle, so really close to 1 degree for every inch you move the rear of the spring down. You would use angled shims to correct pinion angle.
If you spring is 59" eyelet to eyelet it would alter your pinion angle 1 degree for every inch the rear of the spring is moved down. (59" radius, 118" diameter times PI = 370.52" circumference. 365 degrees in circle, so really close to 1 degree for every inch you move the rear of the spring down. You would use angled shims to correct pinion angle.
That's true. Since I'm loaded, I don't think the leaf spring will get a chance to drop a lot on the road, maybe on dirt roads but I seldom go there just state and national parks
OrioN
2008 2500 170" EXT
If, like me, and add helper springs and a lift spacer and actually obtain lift, then you will need to adjust the shocks. I did that my drilling new shocks mounting holes above on the bottom hangers.
Here of picture of me now next to 'you' now. Look at my rear bumper height:
You gained a lot of ground clearance by the picture.
This is me in SW GA. My driveway here is flat.
Right now the ride heights are even 4 inches at the front and rear tire to fender.
But my driveway at my second house in Kennesaw GA has a steep transition from the road level and it scrapes my bike rack.
So the need to lift the back by about 1.5" is enough for me.
This is me in SW GA. My driveway here is flat.
Right now the ride heights are even 4 inches at the front and rear tire to fender.
But my driveway at my second house in Kennesaw GA has a steep transition from the road level and it scrapes my bike rack.
So the need to lift the back by about 1.5" is enough for me.
Back to flipping the leaf spring hanger.
The hanger has left and right tabs welded to a hollow tube ends where the lower mount bolt goes thru.
The flip will subject these tabs welded joints in compression which is stronger than when it is currently in tension.
I will flip it.
The hanger has left and right tabs welded to a hollow tube ends where the lower mount bolt goes thru.
The flip will subject these tabs welded joints in compression which is stronger than when it is currently in tension.
I will flip it.
Andy @ Van Compass
Well-known member
I suggest you read this article so you get a more exact understanding of the spring forces, their dynamic behavior, and how you'll be changing them:
You're going to change your pinion angle significantly. Basically if your spring has say a 5* angle now, flipping the shackle will net in a -5* angle, and a ~10* delta at the pinion. When lifting with a parallel block, the axle does not rotate, so while the pinion angle changes, it is changing an equal amount at the other end, all things being equal. On a driveshaft without a double cardan/CV, this is critical and even more so with 2, and 3 piece units since you're trying to balance all the combined resonant frequencies.
Changing the spring datum line is also going to change your roll center axis and how the vehicle behaves dynamically, but you will at least have wheelbase on your side there. Point being, it'll still be moving that metric in the wrong direction for overall stability.
You do need to move the bump stop down, because you're changing the ride height without changing the arc of the spring. In doing so, you will be able over compress the leaf, invert it and kill the rate quicker than before. The outcome is likely going to be opposite of what you desire. The correct fix is to increase spring rate to counter the weight/sag and get the ride height up, or, a block if you find the spring rate to your liking. If you look at our rear Striker lift kit, it really is everything needed to do this correctly, there is no 'fluff' in there because we want to charge more.
I've done this on several vehicles, and spend a lot of time playing and learning about leaf springs over the last 20 years. They are no where near as simple as everyone wants them to be in their head. It took 3 design revisions, and 4 different springs before I got the front working right on my old leaf sprung, 1-ton crawler:
Either way, best of luck in the learning process. It's fun to experiment, if nothing else. The 3500 Sprinters use a compression shackle, for what it's worth.
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You're going to change your pinion angle significantly. Basically if your spring has say a 5* angle now, flipping the shackle will net in a -5* angle, and a ~10* delta at the pinion. When lifting with a parallel block, the axle does not rotate, so while the pinion angle changes, it is changing an equal amount at the other end, all things being equal. On a driveshaft without a double cardan/CV, this is critical and even more so with 2, and 3 piece units since you're trying to balance all the combined resonant frequencies.
Changing the spring datum line is also going to change your roll center axis and how the vehicle behaves dynamically, but you will at least have wheelbase on your side there. Point being, it'll still be moving that metric in the wrong direction for overall stability.
You do need to move the bump stop down, because you're changing the ride height without changing the arc of the spring. In doing so, you will be able over compress the leaf, invert it and kill the rate quicker than before. The outcome is likely going to be opposite of what you desire. The correct fix is to increase spring rate to counter the weight/sag and get the ride height up, or, a block if you find the spring rate to your liking. If you look at our rear Striker lift kit, it really is everything needed to do this correctly, there is no 'fluff' in there because we want to charge more.
I've done this on several vehicles, and spend a lot of time playing and learning about leaf springs over the last 20 years. They are no where near as simple as everyone wants them to be in their head. It took 3 design revisions, and 4 different springs before I got the front working right on my old leaf sprung, 1-ton crawler:
Either way, best of luck in the learning process. It's fun to experiment, if nothing else. The 3500 Sprinters use a compression shackle, for what it's worth.
My calculations on pinion angle change:
Shackle drop=3 inches
Shackle flip drop=6 inches
Axle drop with shackle flipped= 3 in
Angle change = 0.1017 radians/5deg
Driveshaft length about 60 inches
Axle drop is 3 inches
Driveshaft angle change = 0.05 radians
Or 2.5 degrees.
Pinion angle change is about 2.5 degrees. Not much shim needed.
Shackle drop=3 inches
Shackle flip drop=6 inches
Axle drop with shackle flipped= 3 in
Angle change = 0.1017 radians/5deg
Driveshaft length about 60 inches
Axle drop is 3 inches
Driveshaft angle change = 0.05 radians
Or 2.5 degrees.
Pinion angle change is about 2.5 degrees. Not much shim needed.
You should confirm with a magnetic protractor. I think your numbers are off. You are moving the back of your spring down 6”- therefore about 6 degrees.
