Alignment question

They were from JBA instructions. You lost me man! What’s positive scrub? Lol new to all this for sure. This will be my sons truck as soon as he starts driving so was wanting to make it nice for him and ended up not going as planned lol.

 

The tire turns on two axis.
Caster is one; SAI(steering axis inlclination) is the other. Both are derived from the UCA and LCA balljoints.
SAI intersects the tire contact patch at just a little bit inboard of center. -12 offset moves that point 1-1/2" further inboard. So you added 1-1/2" of positive scrub. This creates a way larger moment arm within the contact patch, latitudinally(side-to-side).
Basically, if you have 0 toe, your tires are toed-out when driven. You can compensate by giving it toe-in so it is zero when driven.
This won't solve the effects of leverage increase, but can help.

 

Running 285/70/17. I did do a cmc. Before my new alignment.

 

So what would be a good all around setting?

 

Here is a good read
https://www.tacomaworld.com/threads/how-to-do-an-alignment-at-home.252256/

 

Depends...
Caster can be subjective or sought for clearance. Toe would depend on offset.

But...you can't really fix 'these things' with an alignment; positive scrub from negative offset, steering linkage geometry from lift, etc.

I will say, I'm not of fan of 3-0-0...
Not so much the 3° caster , but the 0° camber and toe.
It shows the knowledge between a static measured alignment and dynamic alignment is lacking. Nor, am I fan of high caster for the sake of clearance alone. Caster to gain leading trail and mechanical advantage over larger diameter tires, sure.

 

I would advise the OP to take some lift out. This should help a lot with the steering linkages effect on bumpsteer.
Alignment; I would advise +3 caster/+0.5 camber/+0.08 toe.
Less offset would be desirable as well, but that can hurt the wallet.

 

What offset are you running?

 

Tacodog- what offset are you running?

 

What is OP?

 

Original poster
Look next to your screen name [op]

 

Oh! lol newbie lol thx

 

I’m no expert, but that does not look like bump steer. As I understand it, bump steer is caused by a suspension geometry that causes the wheel to steer as the wheel follows its range of motion. To feel it’s effect, you would need a larger suspension range of motion than shown in your video

What you appear to have is a stability problem. The wheels can’t figure out which direction they want to go. I think the post about scrub radius and toe-in is probably your best advice so far.

https://m.youtube.com/watch?v=SUDMEd1bMZI

 

So it’s probably my wheel offset? I know there’s others running the same offset but not claiming and steering issues. Maybe they are just dealing with it?

 

I've helped several like yourself in private messaging.
I don't think you've posted your alignment numbers.

 

As @splitbolt said, it's possibly a combination of wheel offset and toe alignment. I've never encountered this myself, but it makes intuitive sense to me.

Watch the video I linked and pay close attention to the part about zero scrub radius.

EDIT: never mind the part about 0 scrub radius. That was a brain fart.

 

-12

 

What is your lift? Shocks, springs, perch setting, etc front and rear. What tires and what pressures are you running? Do you still have the sway bar on? Did you add spacers for the sway bar. We need more info on what you're running. I'm lifted same height on 33s and factory uca. My caster is 1.8 and have no bump steer or clearance issues with 0 offset.

 

3/2 supreme suspension, factory struts, Bilstein 5100 rear, JBA uppers, 285/70/17 nitto graps, after two sets of KO2s, method 301 17x9 -12 offset. Sway bar is connected no drop installed