F-bod off topic: Help getting truck to handle properly. Long.
07-29-2004, 10:36 PM
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F-bod off topic: Help getting truck to handle properly. Long. I wasn't able to dig up any info in any of the truck forums on this site, or others. I'm hoping there are some handling gurus in this section that could help me out.
About the truck: K1500 Silverado (4x4). Torsion bar front end. Leaf rear. This "roadmaster suspension" in the sig is a helper coil spring that keeps the rear leafs in a natural curved state. (they've done nothing but help me here - they're like helpers and mild sway bars all in one). 1.25" factory swaybar up front. None out back.
I'm running +4.5 caster, -.2 camber, 0 toe. (stock specs are staggered, and one wheel is looking for a lead via caster, the other via camber.
). I leveled the truck side to side, and went with my little custom specs. All are within limits of the stock specs.
The truck handles good on a nice flat road. It handles great (for a portly truck) in a set of curves. If the road has any camber, or if I'm on an uneven backroad, the truck gets right under my skin.
I've got two major problems plaguing me.
1st problem: The main problem. Getting my torsion bar front suspension setup properly.
GM really missed the boat with weight distribution on these 4x4 trucks. The battery, front differential, front driveshaft, transfer case, and 24 gal gas tank, are all on the DRIVERS side of the truck. The passenger side only has the jack and exhaust system. WTF were they thinking?
I can level the truck from side to side, but it feels as thought the torsion bar spring rates (or keying), and the weight distribution is against me. On uneven roads, certain corners or sides of the truck feel as though they defy gravity or the laws of physics.
If the camber of the road tilts to the curb - I'd expect the truck to do the same. No - at times it will decide to lean the other way. This is measureable outside the vehicle. From the drivers seat, it feels as though when the truck leans, it "pivots" on the drivers side front wheel, as if it has too much preload/spring rate under it. The front passenger side of the truck feels "light", and it easily rises in the above situation.
The only way to combat this, is to go ahead and set the truck up with a built-in lean to the drivers side. This bothers me to no end. I can't have a bran' new truck leaning. The dealer is no help. "It's within spec.", they say.
Anyone have any help with this? I don't have any direction with this problem.
I've got the preload set on the torsion bars with my own little method. I remove one t-bar adjuster bolt from one side of the truck. All the preload is taken away, and that side of the truck drops to the bump-stop. I set the other (still preloaded) side to a certain measurement UNDER my own/personal 'desired ride height' spec. I record the bolts lengh with a dial-caliper. I remove it, and do the same to the other side of the truck. When done, I insert both adjuster bolts to my recorded numbers, and both torsion bars combined get in the ballpark of my 'desired ride height', which I measure at the front fenders to ground. What I'm trying to do is assure that each side of the truck is putting an equal amount of needed preload on the bars.
Does this sound like a legit method?
2nd problem: Front sway bar issues. A sway bar should be simple enough, right? No.
If I level the truck from side to side with the end-links loose (measuring from front fenders to ground), the drivers side end-link has about 3/8-1/2" of "free play" between the lower control arm, the center piece of the end-link, and the sway bar. (The passenger side end-link is supporting the sway bar during this). When I snug everything down, and it throws off my side to side leveling. It "tugs down" on what feels like an already over-spung drivers side front wheel. (see above). The passenger side end-link bushings look distored and overworked. Again... WTF.
Putting the end-link/sway issue, the torsion bar spring rate issue, and the odd alignment specs together - it really seems as though GM designed this truck to lean to the drivers side, right from the factory.
I've got Energy Suspension end link bushings, and sway bar bushings here. They are of no help AT ALL - if anything, they magnify the handling issues.
I've tried "shimming" the drivers side end-link to take up this "slack", but I don't feel as though it's a proper fix. The truck still handles odd.
With the sway removed, the truck follows the road properly and generally felt good as long as I didn't try turning.
Right now the only think I can think of is a set of huge Hotchkis sways front and rear. I kind of feel like it's a band-aid - but I'm not sure if what I'm feeling is a characteristic of a single-sway vehicle.
I've been bugging Sway-away about some stiffer torsion bars (with multiple keying options) that I hear they are working on. Nothing yet.
Distant future mods are starting to encompass ditching the 4x4 system, swapping in a 4L80, and relocating the battery.
At this point I'm so fed up with this, I'm ready for just about any mod needed. If I can get any help or direction with these problems, I'd be very gratefull.
Thanks,
-marc
About the truck: K1500 Silverado (4x4). Torsion bar front end. Leaf rear. This "roadmaster suspension" in the sig is a helper coil spring that keeps the rear leafs in a natural curved state. (they've done nothing but help me here - they're like helpers and mild sway bars all in one). 1.25" factory swaybar up front. None out back.
I'm running +4.5 caster, -.2 camber, 0 toe. (stock specs are staggered, and one wheel is looking for a lead via caster, the other via camber.
). I leveled the truck side to side, and went with my little custom specs. All are within limits of the stock specs.The truck handles good on a nice flat road. It handles great (for a portly truck) in a set of curves. If the road has any camber, or if I'm on an uneven backroad, the truck gets right under my skin.
I've got two major problems plaguing me.
1st problem: The main problem. Getting my torsion bar front suspension setup properly.
GM really missed the boat with weight distribution on these 4x4 trucks. The battery, front differential, front driveshaft, transfer case, and 24 gal gas tank, are all on the DRIVERS side of the truck. The passenger side only has the jack and exhaust system. WTF were they thinking?
I can level the truck from side to side, but it feels as thought the torsion bar spring rates (or keying), and the weight distribution is against me. On uneven roads, certain corners or sides of the truck feel as though they defy gravity or the laws of physics.
If the camber of the road tilts to the curb - I'd expect the truck to do the same. No - at times it will decide to lean the other way. This is measureable outside the vehicle. From the drivers seat, it feels as though when the truck leans, it "pivots" on the drivers side front wheel, as if it has too much preload/spring rate under it. The front passenger side of the truck feels "light", and it easily rises in the above situation.
The only way to combat this, is to go ahead and set the truck up with a built-in lean to the drivers side. This bothers me to no end. I can't have a bran' new truck leaning. The dealer is no help. "It's within spec.", they say.
Anyone have any help with this? I don't have any direction with this problem.
I've got the preload set on the torsion bars with my own little method. I remove one t-bar adjuster bolt from one side of the truck. All the preload is taken away, and that side of the truck drops to the bump-stop. I set the other (still preloaded) side to a certain measurement UNDER my own/personal 'desired ride height' spec. I record the bolts lengh with a dial-caliper. I remove it, and do the same to the other side of the truck. When done, I insert both adjuster bolts to my recorded numbers, and both torsion bars combined get in the ballpark of my 'desired ride height', which I measure at the front fenders to ground. What I'm trying to do is assure that each side of the truck is putting an equal amount of needed preload on the bars.
Does this sound like a legit method?
2nd problem: Front sway bar issues. A sway bar should be simple enough, right? No.
If I level the truck from side to side with the end-links loose (measuring from front fenders to ground), the drivers side end-link has about 3/8-1/2" of "free play" between the lower control arm, the center piece of the end-link, and the sway bar. (The passenger side end-link is supporting the sway bar during this). When I snug everything down, and it throws off my side to side leveling. It "tugs down" on what feels like an already over-spung drivers side front wheel. (see above). The passenger side end-link bushings look distored and overworked. Again... WTF.
Putting the end-link/sway issue, the torsion bar spring rate issue, and the odd alignment specs together - it really seems as though GM designed this truck to lean to the drivers side, right from the factory.
I've got Energy Suspension end link bushings, and sway bar bushings here. They are of no help AT ALL - if anything, they magnify the handling issues.
I've tried "shimming" the drivers side end-link to take up this "slack", but I don't feel as though it's a proper fix. The truck still handles odd.
With the sway removed, the truck follows the road properly and generally felt good as long as I didn't try turning.
Right now the only think I can think of is a set of huge Hotchkis sways front and rear. I kind of feel like it's a band-aid - but I'm not sure if what I'm feeling is a characteristic of a single-sway vehicle.
I've been bugging Sway-away about some stiffer torsion bars (with multiple keying options) that I hear they are working on. Nothing yet.
Distant future mods are starting to encompass ditching the 4x4 system, swapping in a 4L80, and relocating the battery.
At this point I'm so fed up with this, I'm ready for just about any mod needed. If I can get any help or direction with these problems, I'd be very gratefull.
Thanks,
-marc
Last edited by marc_w; 07-29-2004 at 10:42 PM.
