Front end sag with snow plow

[Supercharged111]

Here's the expectation: EVERY truck is gonna be nose low when carrying a snow plow. You cant have it any other way.

Cranking the torsion bars will affect caster mainly. Caster does not affect tire wear. Yes, too is affected, depending on how much drop you encounter.
So how heavy is your plow, and how much of the winter do you have the plow on?
If you put on 3k miles all winter long, and 200 with the plow on, then set to factory spec.
If you put on 3k miles all winter long, and 2000 with the plow on, then set it to the positive (toe-in) end of the spec.

Here's my experience: 3/4 ton bars on my Yukon Denali. Western Unimount is already on, and will be till March. I cranked the bars, I leave them cranked. Caster is set as high as I can.
Camber is factory spec.
Lastly, I'm toed-out from spec (should be .24, I'm at .10)

Tires seem to wear well and that's what means most to me.

Ride height absolutely affects toe, I know you've heard of bump steer.

 

[Nad_Yvalhosert]

Ride height absolutely affects toe, I know you've heard of bump steer.

Bump steer is not affected because you dont change the mounting position of the steering arms on the knuckle, or the position of the centerlink (thus the mounting point of the inner tie rod)

Having the mounting points in their OE locations, and going through the factory range of travel, regardless of ride height, WILL NOT cause bump steer

 

[Supercharged111]

Bump steer is not affected because you dont change the mounting position of the steering arms on the knuckle, or the position of the centerlink (thus the mounting point of the inner tie rod)

Having the mounting points in their OE locations, and going through the factory range of travel, regardless of ride height, WILL NOT cause bump steer

Bull fvkk!ng ****. Measure toe, jack up your truck, and measure again. Report back with your findings. I have mine.

 

[Nad_Yvalhosert]

Toe-in and Toe-out doesnt cause bump steer.

Edit: let me rephrase. If its aligned and is in symmetry, the equal amounts of toe-in or toe-out wont cause bump steer

 

[Nad_Yvalhosert]

Bull fvkk!ng ****. Measure toe, jack up your truck, and measure again. Report back with your findings. I have mine.

It's impossible to drive my truck when Im jacked up. I would never do that. Besides, I think that's illegal in at least 38 states, and a few Canadian provinces. Dont know about Mexico though...

 

[Nad_Yvalhosert]

What are the knock outs?

When you remove the upper control arm cam bolts, the hole in the frame pockets are perforated. There's a tool to remove metal on either side of the hole, making it into a slot. Then, during alignment, the tech can rotate the cam bolt, adjusting the UCA into proper position.
That's how all GMT 400s

(except for the C3500HD, in case Mr Supercharger11 wants to fact check me)

are aligned. If "one and only alignment shop in town" didnt do this, they dont know how to align your, or anyone else's truck. And likely hasnt performed a proper alignment on one since 1988...
Go somewhere else, and never look back

 

[evilunclegrimace]

Bump steer is not affected because you dont change the mounting position of the steering arms on the knuckle, or the position of the centerlink (thus the mounting point of the inner tie rod)

Having the mounting points in their OE locations, and going through the factory range of travel, regardless of ride height, WILL NOT cause bump steer

Here is some light reading on the subject,

What is bump steer and how does it affect you? | Auto-Bits LLC

You're enjoying a spirited drive through the winding roads of the countryside when suddenly, you've found yourself fighting with the steering wheel to keep the thing on the road. An episode like that will either leave you feeling exhilarated or grappling with the idea that you possibly brushed...

auto-bits.com

 

[evilunclegrimace]

Toe-in and Toe-out doesnt cause bump steer.

Edit: let me rephrase. If its aligned and is in symmetry, the equal amounts of toe-in or toe-out wont cause bump steer

Bump steer is caused when the toe angle is changed by the suspension moving up and down.

 

[Nad_Yvalhosert]

Bump steer is caused when the toe angle is changed by the suspension moving up and down.

And part 2 of that is: and when the cross toe difference is enough to cause a steering direction change not related to steering wheel movement.

Meaning, if the vehicle bounces up or down and the tires move in or out at different rates.
From a poor, non symmetrical alignment.

If the mounting positions of the tie rods do not converge at instant center, bumpsteer occurs. And how does instant center change? Mounting location of the inner tie rod or steering arm on the knuckles is out of position.

Like I said in a previous post, if aligned correctly, going through the factory range of travel over a bump will not cause bump steer. It must be something else.

 

[Erik the Awful]

Like I said in a previous post, if aligned correctly, going through the factory range of travel over a bump will not cause bump steer. It must be something else.

It depends on how well the suspension was designed. Many older factory systems have bump steer, and at the time nobody cared about bumpsteer unless it was really bad. I think it was only with the advent of computer modeling that engineers got a solid handle on what causes it. Our trucks have a bit of bumpsteer, but it's not bad considering when they were built.

Generally speaking, you want the tie rods to be equal length to your control arms (considering that the control arms are equal length), and parallel to them. With unequal arms, you want to be able to draw a line between the control arm mounting points and have that line intersect the tie rod mounting points.

Toe has a minor effect, even if the mounting points are factory. If you're toed too far in, the arc of motion of the tie rod is shorter than the arc of the control arm. If you change the mounting point, you can get some crazy bumpsteer.

My race team used to field a Toyota MR2. We used a "bumpsteer eliminator" kit when we lowered it, but then the team captain also did some other suspension mod to it. The bumpsteer eliminator actually made the bumpsteer worse - it moved the outer tie rod mounting from the bottom of the control arm to the top. Hitting a bump on a straightaway made the car dart a full foot sideways. We figured out what was happening when we jacked the car and watched the wheels toe out as it rose.