How to stop side to side rocking?

[tanglefoot]

I was thinking (I know, I'm surprised too) and I guess the remedy depends a lot on whether the rocking is initial as soon as the tire encounters the bump or residual rocking continuing after the bump.

In my case it was residual--hitting the bump would begin a big lean and then the rig would sway side-to-side about two more times post facto. That is what the sway bar has almost eliminated. Now it feels much less like it's about to flop over on its side.

If it's the initial sideways movement you're trying to remedy, the solution might be a less-responsive suspension with more squish and free movement, such as disconnecting the sway bar, prying apart the leaf-pack clips, etc. OME springs and shocks are great for this--soaking things up while the truck body continues on close to the same trajectory.

My previous rig was in a different spectrum. It was an '84 full-sized Bronco that rode like jello. Instead of the passengers' heads swinging from side-to-side on the trail, it made everyone's hips gyrate, hula-style.

 

[DaveInDenver]

Old junk, but for comparison I also run OME Dakar heavy springs + heavy shocks in rear and 25mm front torsion (ironically Sway-A-Way) + heavy shocks in front. Sway bar lllooonnnggg gone and I have a WilderNest. No swaying. I think it's a spring rate and matched damper problem. Your spring rate isn't directly tied to the lift height, they can be and often are independent.

The goal is to get the right ones, then match the damper to the rate and travel. My first instinct would be to try higher damping shocks. But either way, you have to adjust any or all of the spring rate, travel, damping. Swaying is an indication of being underdamped for the spring rate, which is usually the way kits are build because the vehicle will seem comfortable with a given load. The problem is that if you are just slightly underdamped or critically damped with partial load, you can oscillate with heavier loads, such as you are finding.

Also make sure you have the tires inflated enough (or maybe over inflated) and that your weight is distributed. Might also try moving heavy stuff and liquids closer to the center line of the truck just to see.

 

[djrez4]

1. If the rear is not sagging then the spring rate is fine....
2. A sway bar will limit articulation and probably make the sway worse....
3. Air bags won't help the problem unless you want to haul more weight in the future....
4. The correct shocks WILL help or eliminate the problem. The reason the trucks sways and then keeps swaying is because the shocks aren't doing or can't do their job. 5100s are an aftermarket shock designed for stock weight trucks. You need a shock that will handle/control the extra weight....
5. Suspension 101. Springs hold stuff up and let said stuff move up and down. Shocks control the movement. I think FOX has some adjustable shocks where you can vary the control/dampening by simply turning a knob....

YMMV RON

This is all you need to know.

 

[jsbasham77]

Im really surprised nobody has recommended Timbren bump stops. This is exactly what they are designed to do and every person that has used them swears by them. I just installed a pair today on my 07 Tacoma. Super easy to install. Even if they didn't completely eliminate your current issue, based on your setup and use of your vehicle, they would still be a huge advantage.
I would definitely check them out. http://www.timbren.com

 

[Pedro]

Our truck although not equipped the same way as yours lessened sway by the addition of OME springs. Even with the preload on your factory springs it is no match for a real load rated spring.

E load tires will also help.

 

[EricBirk]

Im really surprised nobody has recommended Timbren bump stops. This is exactly what they are designed to do and every person that has used them swears by them. I just installed a pair today on my 07 Tacoma. Super easy to install. Even if they didn't completely eliminate your current issue, based on your setup and use of your vehicle, they would still be a huge advantage.
I would definitely check them out. http://www.timbren.com

Timbrens are designed for anti-sway? I thought they were designed as bumpstops?

Listen to GSRON. Shocks control the "rate" of suspension movement, springs just hold up a load...

 

[Pedro]

That is only part of it. The fronts is lifted by adjusting the perch height on the 5100's. That isn't giving him the correct spring rate for a loaded truck.

 

[brandonhedberg]

The front seems fine. It's more firm now than when it was stock height. The preloading has helped.

I'm thinking the rear shocks aren't dampening enough (compression and/or rebound) for the additional load and higher center of gravity (virtual load?).

I'll be contacting Bilstein and Fox.

Thanks.

 

[Pedro]

you should also contact ARB. OME makes a specific shock for "heavy constant load" typically for full roof racks or RTT's. They may be able to cross reference something that will fit your application.

and your preloaded springs in the front are firmer now, but what you are missing is the increase in spring rate, it makes it harder to sway. and the front has a good impact on what the rear is doing.

 

[brandonhedberg]

Tires? I loaded up the truck for a trip and the swaying was horrible. Tires were at 38psi cold. So I upped the pressure to 48psi cold (max is 50). Swaying gone!

Im very surprised the tires would flex that much.

So, the question. Should I swap to a higher load rated tire or keep the load c tires at higher pressure? This is a 2004 double cab tundra with near GVWR (when adventuring) with 265/70/15 BFG AT Ko load c tires.

Thanks.

 

[Pedro]

Go E load rated tires. I have them on our GX and they handle beautiflully.

you may have to go up to a 16" wheel though. but they are easy to find on Craigslist.