Alignment issues or something else?

[linuxgod]

I'll measure again today and see what the difference is side to side, but I believe it was only .5" and maybe 1-1.5" front to back. I hope you're right about the rear height being an issue, but I would assume when I tow it would correct since the rear sags making the rig level front to rear. But the only changes that directly corelate to when this issue became noticeable was the rear trim packers to give me some rake back and replacing my beat up coil isolators.. otherwise my mods had been there and there wasn't an issue.

When I had this similar issue on my daily, the root cause of that ended up being steering stabilizer bushings. I haven't seen anything on here about someone replacing KDSS bushings to fix an issue like this, but maybe that's a place to start?

I'm mostly thinking severe rear height might be pushing your rear end off, and perhaps a rear panhard rod would correct it. But it's my understanding that the shift should be straight and just offset (like a crab walk), not directional, so I'm not sure that's it. Which is why with my truck I was leaning towards slightly different CV angles due to a lean causing my torque steer. I actually put a 1" diff drop kit in to get the CVs back to their original angle, which did seem to reduce my torque steer further, though not completely eliminate it.

Trailer makes it worse because weight applied to the rear (no matter the height) results in the front rising up. Go measure your front height before and after hitching (even with WD properly set) and you'll see what I mean. The extra 1/2" or 1" of lift you get up front when the trailer is hitched in the rear is effectively a taller lift, which means your CVs are at a steeper angle and all of your alignment specs (which were done when you were unhitched) are "wrong". It's like you aligned for a 2" lift but then swapped it for a 3" lift. So yes the trailer helps squat the rear, but the opposing impact on the steer axle is why you're squirrelly.

When the tech did my alignment he actually jacked the front of the vehicle up by the frame to similar a ~3/4" additional front "lift", as if I was towing. It's a marginal improvement at that point though.

Sway bar or other bushings could be worn and causing issues, for sure. My sway bar end links are tight but the bushings definitely have a bit of old rubber cracking going on. If you're not confident in the condition of your suspension components, I'd put it on a lift and check everything out. Worn tie rods for instance might lead to wandering and loose steering, though if it's only on hard acceleration and not also when cruising I'd be suspect in my own diagnosis there.

 

[linuxgod]

On the face, it may not seem like it is. But it's a contributor, or arguably one of the root issues. Can you work around it to minimize it's effects, yes. Fundamentally, offset and scrub radius geometry problems can create opportunities for other issues to magnify steering pull/push.

@linuxgod - you're on +25 and 34" tires (optimal is +40 offset, or 15mm diff). If I'm not mistaken, @afgman786 is on +18 and 32.7" tires (optimal is +40 offset, or 22mm diff). It's a a more aggressive setup and geometry disparity, which has more vulnerability to these types of issues. Yeah, it's possible to isolate and minimize if he can pinpoint other causal issues.

Anecdotally, I noticed mild scrub radius pull/push on +35 offset and 33.2" tires (optimal +43, or 8mm diff) in extreme uphill full throttle pulls. Now with 34.5" tires and +35offset, which puts it perfectly on point, there is no pulling to speak of.

Yeah he's more aggressive, but he's also saying things were fine with his tire/wheel combo before. The issue seems to have come up recently. That makes me think scrub radius is only a small part of the equation, if anything at all, particularly if heavy braking isn't causing any squirreliness.

My experience with my rear springs swapped and causing a >1" lean is anecdotal and atypical. However what I experienced when towing like that was exactly what @afgman786 described - hard pull under heavy acceleration, letting off the accelerator pulls back to the other side, but hard braking has no impact on handling. Fixing my lean made it better, diff drop helped a bit, fine tuning the alignment helped a small bit. Granted while the alignment shop I used specializes in only alignments and does a lot of track cars and lifted trucks, my alignment specs are not what others run around here, and it's entirely possible my additional caster or low camber adds highway stability at a cost of also adding some small torque steer under full throttle acceleration.

I do think adjusting the SPCs and adding +1 or+2 degrees of caster at the ball joint, then realigning, would be wise. If you're running at max caster on the LCA cams and only at 3 degrees, you're getting less when your trailer is hooked up and effectively lifting the front of the truck. IMO add +1 degree and then back the cams off slightly to try and max out caster, though I think that will be another small improvement but not the underlying cause.

For me, +25 offset will just be my excuse to eventually go to 35s

 

[afgman786]

@linuxgod axle doesn't seem to be misaligned left to right from looks, but I plan on measuring when I get home from the office. I get your point on whether I give it rake or not the trailer lifts the front a bit and lowers the weight on the front axles. What stumps me is why did I not have this issue towing same trailer and rig and had rear squat, then added a small amount of rake and replaced broken rubber pieces and then all of a sudden on a mild climb with the same trailer and rig I've got the wheel turned to 10 o'clock to track straight.

@TeCKis300 yea my offset isn't optimal so it walked a bit with my MTs, nothing I didn't expect. The "winter tires" are Goodyear ATs that are very street biased and they don't wander on the road at all the way my MTs did. As @linuxgod mentioned that isn't what I'm complaining about. Also the 200 looked silly without spacers when lifted, plus I plan on going to big meats. I'll still be to low on offset but closer.

@linuxgod are you saying push my caster to 4 since I'm at 3, putting me outside of factory specs? If that's the case I'll have to go to a specialty shop since the dealer doesn't know how to adjust SPCs and as simple as it looks I'd rather have a specialty shop do that if it comes to that.

 

[TeCKis300]

Yeah he's more aggressive, but he's also saying things were fine with his tire/wheel combo before. The issue seems to have come up recently. That makes me think scrub radius is only a small part of the equation, if anything at all, particularly if heavy braking isn't causing any squirreliness.

My experience with my rear springs swapped and causing a >1" lean is anecdotal and atypical. However what I experienced when towing like that was exactly what @afgman786 described - hard pull under heavy acceleration, letting off the accelerator pulls back to the other side, but hard braking has no impact on handling. Fixing my lean made it better, diff drop helped a bit, fine tuning the alignment helped a small bit. Granted while the alignment shop I used specializes in only alignments and does a lot of track cars and lifted trucks, my alignment specs are not what others run around here, and it's entirely possible my additional caster or low camber adds highway stability at a cost of also adding some small torque steer under full throttle acceleration.

I do think adjusting the SPCs and adding +1 or+2 degrees of caster at the ball joint, then realigning, would be wise. If you're running at max caster on the LCA cams and only at 3 degrees, you're getting less when your trailer is hooked up and effectively lifting the front of the truck. IMO add +1 degree and then back the cams off slightly to try and max out caster, though I think that will be another small improvement but not the underlying cause.

For me, +25 offset will just be my excuse to eventually go to 35s

I'm with you and I'm sure the OP is trying to find a solution outside of scrub radius, because he's made it work before. There is something else going on that we haven't pinpointed that is related to alignment/lean/axle what have you.

I'm just trying to convey that everything is magnified with aggressive scrub radius. As you mentioned yourself, alignments are touchy, and towing can change the attitude of the vehicle, seemingly minor things exacerbate symptoms. This is what suspension geometry is about, because great suspension geometry makes other minor discrepancies less symptomatic, with less toe steer or alignment changes as the suspension moves. If I can relate this to a domain you're familiar with - software: trying to address a bug due to fundamental architectural issue, solving the bug can alleviate the immediate issue, but there's larger issues at play. The architecture is a not so small part of the equation.

 

[afgman786]

Height measurements, all fender to center of hub roughly.
Front driver: 23"
Front passenger: 22.5"
Both rear: 24"

Also pictures of KDSS bushings and LCA bushings, the LCA bushing don't look like they are bound up to me just dry which I'd expect for an 08 with 186k.

 

[TeCKis300]

Height measurements, all fender to center of hub roughly.
Front driver: 23"
Front passenger: 22.5"
Both rear: 24"

Also pictures of KDSS bushings and LCA bushings, the LCA bushing don't look like they are bound up to me just dry which I'd expect for an 08 with 186k.

This is helpful. I'm realizing your lift is pretty aggressive. I do believe your latest issues are attributable to the 20mm spacers you installed, as that puts you way up there at 24" wheel center to hub, which is roughly a 3"+ lift.

The panhard will pull the rear axle towards the driver side of the centerline notably at that height. Additionally because of the displacement, the trailing arm geometry will change the thrust angle again towards driver (as we can see in the alignment). The rear axle is putting power down offset of center, and is thrusting towards driver causing the overall vehicle to pull to the right. Combine that with aggressive offsets, and I can understand why.

@linuxgod is on the right path with recommending an aftermarket panhard to re-center the rear axle. Toe steer will still be an issue when the suspension cycles, but at least in steady state ahead, should really help with the pull.

 

[afgman786]

This is helpful. I'm realizing your lift is pretty aggressive. I do believe your latest issues are attributable to the 20mm spacers you installed, as that puts you way up there at 24" wheel center to hub, which is roughly a 3"+ lift.

The panhard will pull the rear axle towards the driver side of the centerline notably at that height. Additionally because of the displacement, the trailing arm geometry will change the thrust angle again towards driver (as we can see in the alignment). The rear axle is putting power down offset of center, and is thrusting towards driver causing the overall vehicle to pull to the right. Combine that with aggressive offsets, and I can understand why.

@linuxgod is on the right path with recommending an aftermarket panhard to re-center the rear axle. Toe steer will still be an issue when the suspension cycles, but at least in steady state ahead, should really help with the pull.

So I'm pulling the trailer and rig this weekend and will get measurements when I load up and see what it drops to. Also depending on how much rake I still have after loading up now that I have the front bumper I might take out 10mm of spacer and see if it helps. I'll be towing the same setup again the following weekend as well.

Figure its easier and cheaper to see if removing the trim packers fixes the issue or at least lessens it to a level I'm fine dealing with before spending money on panhard and adjustable trailing arms.

 

[duggy]

Not sure if this helps but here is my recent alignment on my ‘10 with a Bilstein 6112/5169 lift (with SPC UCAs and OME rear coils) performed by a Land Cruiser knowlegable shop. Tracks good with these numbers. I measure 23” at the rear. 21.5” at the front

View attachment 2614946

This is a great alignment. I'm proud to have these numbers posted

To answer the OP's question, your pull is being caused by the caster. The drivers side should be offset .2* or .3* less than the passenger side to offset for any crowns in the road. I would try this and report back to us. The rear suspension most likely has nothing to do with your pull.

 

[afgman786]

This is a great alignment. I'm proud to have these numbers posted

To answer the OP's question, your pull is being caused by the caster. The drivers side should be offset .2* or .3* less than the passenger side to offset for any crowns in the road. I would try this and report back to us. The rear suspension most likely has nothing to do with your pull.

Thanks for the input. I'll reach back out to my service advisor and see what they normally recommend for our crowning. I do believe normally it is higher on passenger side in the past for me, but since I mentioned getting them around 3 I think they were doing exactly what I said and not also throwing in what should be done.

As silly as the rear height might sound that is 1 of 2 things I did that directly made this issue apparent. So I'm not discounting it, especially with how easy that is to do.

 

[PhuckItImDone]

I'll be watching this, as my truck is headed for an alignment tomorrow to cure a pull to the right. Ill report back with results.

 

[Hoosier Daddy]

I'm the dumbest guy in the room here, so forgive me if this is just obvious to everyone else.

But why aren't those cracked/broken LCA bushings high on the list of suspects (and wondering what the rear control arm bushings look like)?

I thought rule #2 (after rule #1, tires) when looking into a pull under load is to rule out worn/torn bushings.

 

[afgman786]

I'm the dumbest guy in the room here, so forgive me if this is just obvious to everyone else.

But why aren't those cracked/broken LCA bushings high on the list of suspects (and wondering what the rear control arm bushings look like)?

I thought rule #2 (after rule #1, tires) when looking into a pull under load is to rule out worn/torn bushings.

That's why I posted the pic of bushing since I know they can play a factor. But then again these bushing have been like this before I had the issue too.. and having 2 known changes then issue rise I can see why people are suggesting I looking at that first.

 

[linuxgod]

@Hoosier Daddy, it depends a bit on how quickly the problem arose, what the symptoms are, etc.

@afgman786 I think you're on the right track, or at least following the right troubleshooting path. Being an IT guy and routinely troubleshooting broken crap, the first rule when a problem arises is to look at the last thing(s) you did and try to undo them (or at least rule them out). From there just make one change at a time. And if you can make one change which will help rule in/out a portion of the potential causes, I typically focus on those first to help narrow down the potential scope. (Not sure that applies in this case, but it's always part of the consideration).

 

[afgman786]

Did the same trip towing this weekend that I did in October, and glad to say this time went way better. I had pull to the right but there was slight pull the entire time, same as when I picked it up after alignment beginning of the week. This time around it wasn't white knuckle when getting on the throttle, there was a little bit of torque steer but in the passing lane I was fine and think getting alignment fixed this week should be all I need. With OBD Fusion I got up to 60% absolute throttle position and I only had to correct a little bit more than I was when cruising which I am willing to accept if it can't get better. I was able to drive 1 handed comfortably the whole time.

October Trip​

March Trip​

- Crazy amounts of torque steer, requiring 2 hands and inducing sway when I would get off throttle from amount of steering correction required - RW on 285/70/17 KM3 (spacers) - 7" drop hitch with trailer not flat when hooked up (not enough drop) - Didn't have many links used on WD hitch because rear axle tires were stuffing into the fenders, the more chains I would add the worse it got. I believe I only used 2 chains worth of tension.

- Small amount of pull to right but was there whether on throttle or not, passing lane made it less noticeable - Stock on 275/70/18 Goodyear AT (spacers) - New larger drop hitch making empty trailer almost flat when hooked up - 4th link on WD hitch, trailer had small amount of lean to the back

Hub to Fender measurements w/ trailer and rig - WD on 4th link: front and rear both roughly 23"
Hub to Fender measurements of trailer and rig w/ NO WD: Front - 23.5" Rear - 22.5"

Plans:
My goal is that going back to the dealership to adjust the alignment again to get rid of the slight right hand pull that I have since having them try and push my caster above 3*. This pull was there after leaving the dealership so I know the trailer did not cause this, this time around. I don't think I will remove a trim packer out the rear since the issue wasn't as bad this time around and manageable, also the fact that I will definitely have rear squat if I do.

I am also planning on running 3 links on WD for the first tank of gas this coming weekend to see if the pull becomes bad again, if so I will crank back to 4th chain. My reasoning is the hopes that the trailer will stay more level so I'm not stuffing the rear trailer tire into the fender on bumps/expansion gaps on the highway. Also looking forward to what the you guys think of my process and provide your input.

 

[afgman786]

Had the alignment worked on again this morning, and I think they squared me away. If anything under real hard throttle I'm getting slight pull to the left instead now. I'll see how towing goes on Thursday but seems like I'll be good to go. Cruising and moderate acceleration she was tracking straight. They spent quite a bit of time on the alignment, taking it for a drive, tweaking, even checked other things to make sure nothing was dragging and so on before handing the keys back over.

 

[TLC2013]

Happy to hear you are working through this with positive results. Here are my numbers from two different alignments for reference. I do notice a slight pull to the right at full throttle that lasts a split second, torque steer, and then disappears. Anything less then full throttle it tracks dead straight.

I’ll double check these Measurements but I think these were my most recent hub to fender numbers:

FD-21 3/4”
FP-21 1/2”

RD-23”
RP-23 1/4”

 

[TLC2013]

Here is an alignment from when I was all stock, and before the 2” tough dog lift. Interesting to see the rear alignment specs change once the lift and larger tires were installed.