Rear end feels like a flat rear tire - Will Traction bars help?

[Monsterdood]

Go easy, this is my first leaf spring equipped vehicle.

Cruising at 65-70 mph on the freeway, the rear feels loose and wallows a bit. Almost like rear wheel steering with the rear wheels steering opposite of the front and making the rear want to rotate around (oversteer) about .5-1 second after the initial steering input. I assume this is a trait of leaf springs in the rear and it is a little unsettling for me. I'm coming from driving an 80 series Landcruiser that has solid axles front and rear and coil springs all around. It has two monster ladder / traction bars for the multi-link rear axle control and it feels much better than the Titan driving on the freeway.

The TPS light came on and I gave the wheel a little input to see if I had a flat and from the way the truck responded, I was sure I had a tire going down pretty quickly. I slowly pulled off the road and found all the tires to have 32 psi. I was a little embarassed to pull off the freeway thinking I had a flat, but also curious why the rear felt like it wanted to come around about 1 second after a steering input as if a rear tire were flat. I did have about 650 lb of gear in the bed at the time, but I have still gotten that sensation with nothing in the bed in subsequent driving.

I imagine the fore-aft play the leaf springs allow creates this weird sensation and I am further thinking that traction bars would really tighten up the rear suspension and make it feel much more planted in a slalom or lane change type of maneuver.

I'm not looking to race on roads or off roads, I just want to make the rear feel more stable and planted in evasive maneavers or even simple lane changes.

Thoughts? Am I on the right track with the traction bars? Everyone talks about axle wrap and straight line feel, but I am curious if the traction bars would assist in the control and stability during these type of maneuvers.

[Sammy Sandbag]

Some thoughts: increase your tire pressure, 32 is a tad on the low side. I run mine at 35-38, others even more. Adding traction bars will do more for axle-wrap/wheel hop than anything, but could help the rear feel a little more solid. A rear anti-sway bar could also help out. But I think a major issue is this:

this is my first leaf spring equipped vehicle.

Hard to compare the two. I think most folks that have driven trucks their whole life will say the Titan has a very good stability and road manners. FWIW, I have the PRG traction bars and love them, but I didn't buy them for any of the reasons you mentioned.

[Monsterdood]

Yeah, the tire pressure may have a small impact, but I think 32 psi is enough to give normal types of response.

And I have driven other trucks in the past (more miles than the Titan so far), just not owned them. And for driving the Titan only a couple hundred miles, this perception really sticks out to me.

[sudden urge]

Hellwig traction springs, sold exclusively at JC Whitney.

[BKW]

It's less about the rear leafs, and more about the lack of weight in the pickup bed. What you are experiencing is nothing new for pickups. Adding weight to the bed will help, adding a rear sway bar will help more. Traction Bars are more about straight line performance. They are designed to eliminate axle wrap/hop.

[Monsterdood]

The effect seems to be weight independant. With the bed loaded to 50% of its payload it did it just the same.

It feels like the rear axle is staying straight in the old lane while the front tires are changing lanes. I can imagine that just making the rear really stiff and maybe adding a sway bar would help this effect, but would make the ride harsher.

Traction bars are all about helping define the allowable path the rear axle can take and it just so happens that prevents axle wrap, but I'm still thinking that it would help prevent the rear axle from becoming non-parallel to the front "axle" (or the equivalent construct for an IFS) and therefore help tighten up the responsiveness without impacting ride quality at all.

Seems like the traction springs would impact ride quality, especially with an unloaded bed.

Thanks for the responses!

[BKW]

I assume all 4 tires are the same make, model and size. If not, that could be the problem.

However, the problem you have, sounds to me like "dog tracking."

This is caused by a broken rear spring leaf.

Did you ever follow another vehicle, and notice that not only could you see the two rear tires, but one of the front tires, too?

When one or more spring leafs break, the rear end will shift over to one side. The vehicle then will proceed done the road, weaving like an old drunk.

Check those leaf springs.

[SirStrider]

I have driven about 1500 highway miles over the past few weeks, and had the same type of feeling. Almost to the point of feeling like towing a trailer with too little weight on the tongue - like a very low amplitude swaying. I was loaded with an A.R.E. topper and about 700 lb. of stuff, with about 2/3 of the weight on or in front of the rear axle. Tires all at 36 psi cold.

Also, even when loaded, the rear feels like it is hopping over rough roads.

So, would I be able to add sway bars and traction bars? I am planning on adding some air bags and doing a little lifting - maybe 3". and adding 2" radflo coilovers to the front.

Was also considering ordering the Helwig Traction Helpers.

Anyone else?

What combo will give the best results???

[BKW]

Adding a sway bar and tractions bars will help considerably. See my second post (#7) in this thread for other possible issues.

I'm no fan of lifted trucks. Changing the geometry may look great, but what it does to the suspension and driveline, can cause all sorts of problems.

At one time, modifying the suspension voided the factory warranty. Now y'all have the Magnusson-Moss Act to fall back on.

[ptgarcia]

Mosterdood,

Does this only happen or rough roads or will it do it on smooth roads also? And it only does it after making a steering input, right? If cruising down a straight highway does the truck track straight or are you constantly having to make corrections?

My trucks are leafsprung and don't exhibit these traits. I'd crawl under the truck and look around for anything loose, bent or broken. Pay particular attention to the axle u-bolts and the shackle. Check for blown shocks while you're under there.

[Monsterdood]

The truck tracks and drives great going straight and the looseness in the rear is during faster lane changes at highspeeds. No crabwalking from it. I can feel the rear "loose" in turns a little bit but giving the steering wheel short and quick inputs left and right staying within a single lane just gives the feeling the rear wants to steer opposite of the front tires and the truck feels a bit unstable.

I really think it is an effect of the stock truck but perhaps there is a mechanical problem making me feel this looseness. If you've ever had a flat rear tire, you will know exactly the feeling I get hile driving. It's as if the rear tires want to keep going straight or even in the opposite direction from the fronts. If I had to guess, I would say the rear tires were at 10 psi, not 32 psi, but even though the TPS light fooled me, the tires are at an acceptable pressure.

I checked the shackles based on some of the clunks / rattling I heard but will grab my creeper and do a full inspection pretty soon to see if anything is out of place or damaged.

This truck has 34k miles and I just picked it up used so the possible reasons for the issue are 1) Me not being used to how a stock titan feels or 2) something is amiss in the rear suspension from the previous owner. I've driven Tacoms and Silverados and have not had this feeling before though....

FWIW, the previous owner took the truck to the dealer complaining of rear suspension clunking but the dealer found nothing. I believe it was the tailgate being loose, but perhaps the bed rattle / clunking is related to this loose rear feel.... I doubt it, but it's possible....

[SirStrider]

Originally Posted by Monsterdood

The truck tracks and drives great going straight and the looseness in the rear is during faster lane changes at highspeeds. No crabwalking from it. I can feel the rear "loose" in turns a little bit but giving the steering wheel short and quick inputs left and right staying within a single lane just gives the feeling the rear wants to steer opposite of the front tires and the truck feels a bit unstable.

I really think it is an effect of the stock truck but perhaps there is a mechanical problem making me feel this looseness. If you've ever had a flat rear tire, you will know exactly the feeling I get hile driving. It's as if the rear tires want to keep going straight or even in the opposite direction from the fronts. If I had to guess, I would say the rear tires were at 10 psi, not 32 psi, but even though the TPS light fooled me, the tires are at an acceptable pressure.

I checked the shackles based on some of the clunks / rattling I heard but will grab my creeper and do a full inspection pretty soon to see if anything is out of place or damaged.

This truck has 34k miles and I just picked it up used so the possible reasons for the issue are 1) Me not being used to how a stock titan feels or 2) something is amiss in the rear suspension from the previous owner. I've driven Tacoms and Silverados and have not had this feeling before though....

FWIW, the previous owner took the truck to the dealer complaining of rear suspension clunking but the dealer found nothing. I believe it was the tailgate being loose, but perhaps the bed rattle / clunking is related to this loose rear feel.... I doubt it, but it's possible....

That is exactly what one of my symptoms are - 4k miles on 2006. Also, if going 70 on smooth and straight highway, tiny corrections seem to "bounce back" from the rear in that trailor towing type situation - I can deliberately undercorrect with no problem, and it goes straight just fine, no crabbing like yours, but that "not quite stable" feeling in the rear. Not to the point of being worried about driving, just a little annoying on a long trip. Gotta fix it.

I may try to get a sway bar while here in Virginia before heading back to Missouri Friday.

If you find anything, let us know. I'll do same. Going to crawl under her today...

[loufish]

I've heard a couple of guy have had the weld on the rear shackles start to tear...I'd double check those...

[Monsterdood]

If you are looking from the side of the truck, where do the traction bars attach to the rear axle? In the middle, below, or above? I am guessing abive where the shocks mount, but just want to double check....

[Monsterdood]

Okay, after some back to back driving in the Landcruiser and the Titan, I've decided that the front end and the steering on the Titan is 10 times better than the Landcruiser and that difference is really what gives me the feeling.

In the landcruiser, there is a lot more play in the steering wheel so minor left right inputs don't do much of anything. Larger inputs have to be exagerated to really do a little weave on the freeway and with an input large enough to steer the front like the Titan, the rear of the Landcruiser feels about the same with a time lag before the rear wheels want to follow the fronts.

So in conclusion, the tight steering, the IFS, and likely the difference in weight over the front and rear between the two give that feeling I initially was worried about in the Titan. I'm sure a rear sway bar would help the feeling, but would cause poor front to rear traction balance when unloaded so I think I'll just get used to the Titan a while longer.

But I do need to do something about one wheel spinning when leaving a driveway and needing to accelerate.... True-trac on the wish list.....