soft ride on the Duramax

[buffblazer]

05 dmax crew cab short bed 4x4. lifted to what i believe is 6 inch lift (6 inch blocks in rear idk about the IFS)

had 37's on it and i went to 35's and turned the torsion bars down 2 inches. now the truck bounces a lot more then it did and floats.

80k miles on the truck unknown about the lift.

so did lowering the torsion bars screw up the ride or did it make the worn out shocks more noticable?

 

[sweetk30]

the t-bars will be stock with the ifs lift. it only lowers the back mount to match the new lower control arm position.

think of the t-bars as a rubber band on the old wooden airplane kits we use to play with as a kid. the harder you wind it up the harder the rubber band got and the more energy it stored.

so the same applys with the t-bars design. you turning the bars down mabe them a softer spring rate from not being as stiff.

if you did some research you might be able to bandaid the problem with stiffer valved shocks to slow up the movement. but its a bandaid.

and stiffer t-bars not gona happen as dmax equiped trucks get the biggest bar already from the factory.

 

[rob h]

I had a superlift bracket lift, so called softride. It came with oil filled shocks and drove real nice, then i had the idea to crank it up and run 37s instead of 35s. I must say it drove like a tank, even with new shocks it rode rough. I had fabtech gas shocks and it helped some, finally i went to bilstein 5150s and that helped alot. If it has sh!t cheap shocks it will drive crappy, the better ones make a world of a diff on a ifs truck. They do make though dual shock hoops for it which might help you...but might be a bandaid.

Im not sure how cranked yours was but mine had 5 inch blocks and an adda leaf in the rear and it was leveled...cranked way up... Usually unless it changed they only make 5 inch blocks, more so 5.5 with the taper for the pinion angle.

I did notice tho when i did my straight axle that without shocks i could cycle the truck with ease. When i added the 5125 dual valves to it that changed it alot, no longer can i cycle it easy.

 

[Fred_M1010]

05 dmax crew cab short bed 4x4. lifted to what i believe is 6 inch lift (6 inch blocks in rear idk about the IFS)

had 37's on it and i went to 35's and turned the torsion bars down 2 inches. now the truck bounces a lot more then it did and floats.

80k miles on the truck unknown about the lift.

so did lowering the torsion bars screw up the ride or did it make the worn out shocks more noticable?

Did you adjust toe after you loosened the torsion bars?
If not you probably have some Toe-out now,
that could account for the floating at least.

think of the t-bars as a rubber band on the old wooden airplane kits we use to play with as a kid. the harder you wind it up the harder the rubber band got and the more energy it stored.

so the same applys with the t-bars design. you turning the bars down mabe them a softer spring rate from not being as stiff.

I don't think that's a good comparison.
As long as you don't crank it up so much that the control arms bottoms out at ride height,
it shouldn't affect spring rate.

I think much of the rough ride associated with torsion bar cranking,
is from the control arms bottoming out on rebound.

The increased angle of the lower control arm should give a slight increase in spring rate when cranking the TB though.
As 1" of wheel travel will result in less angle on the TB, than if the control arm is horizontal.
But I doubt that would even be noticeable...

 

[6.2Blazer]

You are increasing the spring rate of a torsion bar if you "crank it up", or vice versa turn it back down. Since you are not physically moving the mounting locations of anything in the front, increasing the spring rate is the only possible way to increase the lift by doing this. I do agree that the poor ride quality many people talk about when cranking torsion bars is a combination of the increased spring rate and forcing the suspension against the droop stops.

For the OP if you "de-cranked" the t-bars 2" from the previous setting, which might of been stock, you could have them forced against the compression stops. The lower control arms lightly ride right on these bumpstops when stock. Lower it 2" and you basically have the lower control arms up against the frame with the exception of a squished out inch of bumpstop and very little suspension travel. This is a quick check...just look under the front and see what it looks like. On my '03 (with snowplow package and thus the heavier t-bars), an '05, and '09 all sitting in the parking lot show the lower control touching the compression stops but it doesn't look like the stops are squished out (under a lot of pressure). You could also jack up the truck from the frame and see how far the wheel droops before there is a gap between them.

 

[Fred_M1010]

You are increasing the spring rate of a torsion bar if you "crank it up", or vice versa turn it back down. Since you are not physically moving the mounting locations of anything in the front, increasing the spring rate is the only possible way to increase the lift by doing this. I do agree that the poor ride quality many people talk about when cranking torsion bars is a combination of the increased spring rate and forcing the suspension against the droop stops.

Ok, I understand how you're thinking, but I respectfully disagree.
I think this is one of those common misconceptions,
that has been repeated so many times, it has become a "truth"

Say that I crank the bars 5 degrees up in the back at the crossmember,
and since the counter force (the weight on the front axle) is the same,
I believe they will rotate 5 degrees at the lower control arm as well.

And by doing that rotate the control arm by 5 degrees,
lifting the front of the vehicle.

And as the TB will be rotated 5 degrees at both ends
(the "twist" would be the same at the new ride height)
the spring rate should be the same...

I can't say I'm 100% sure of this though, but I'm always open for a good debate