Need Help, Bump Steer

Hey guys, I need some help tracking this bump steer down. Here's the story. When I lifted my truck I lifted the front first and got an alignment because I wasn't sure if I would have time to lift the rear before my trip. 3" lift up front with 185/75r16 Duratracs all around. When I drove it home from the alignment it felt great, no steering issues at all. The next day I had time to install my rear Dakar leaf packs (third leaf removed). After lifting the rear I had bump steer. I figured it was the caster so back to the alignment shop. I had them set 3.5 positive caster (from what I've read on here that's what most people recommend) and align everything else. Still have bump steer. Not terrible but I can feel it driving on pavement over small stuff. The wheel always re-centers itself but I can't figure out why I have it. So my question, why did I only get bump steer when I lifted the rear?

Vehicle specs:
2016 SR5
Bilstein 5100 with OME 888s
Dakar leaf pack
Light Racing UCAs
285/75 r16 Duratracs set at 35 psi.

 

Hood skewp?

 

What?

 

We put additional caster on our lifted-larger wheeled trucks to correct/improve the relationship between SAI and the tire.
When you lift the rear, you change this relationship; more so when you deviate from factory rake.
Caster as it relates to bump steer, usually means you have too much. Weight transfer to the front probably didn't help any either.

 

So you're saying I have too much positive caster? Before I had 2.3 after the rear was lifted and now that I have 3.5 it seems like it has less bump steer but it's still there. So if I were to lower the front about .5" it might help correct the rest of the bump steer?

 

Hmmmm....
Would you mind describing what you think is bump steer?
Aftermarket wheels? Specs?

 

Bump steer as in my one of my front tires hitting a quarter on the road and it turns my steering wheel a little lol. It always recenters but the steering wheel still pulls to one side then centers going over bumps that you wouldn't even feel in any other truck. Wheels are procomp 8" with 4.5" back spacing to make it center. Tires 285/75/r16 Duratracs at 35 psi. Someone with a 2nd gen said that he had bump steer with the duratracs until he aired down to 35 from 42. Should I try running 30 psi and see what happens?

 

I think you're on to something...
Bigger tires don't require as much psi to attain their load rating.

The converted tire placard pressure for your new tire type and size, is 30 psi.
You're ideal pressure might be even lower.
You might want to do a chalk test.

 

shhhh.... there are a few members who think all E tires needs 60psi+ and other tires need 40+

 

Well I dropped it to 30 and still have it. I think it's the fact that I still have camber. The alignment shop wouldn't give me 0 camber even though most guys are running it with lifts. Hopefully I can find someone that will set my alignment the way I want and see if that helps

 

What did they set camber at?

Do you have those bilsteins preloaded at all?

 

The bilstein 5100s are on the 1 setting. If I remember right they set camber at 1.9 degrees

 

That's a lot of camber. Bilsteins need to be on the lowest setting with 888's

 

Well with the 6112s on the 0 setting it is about the same as the 5100s on the 1 setting. And yes, you can see the camber on it, top of the tires are out more than the bottom

 

Problem I think is, you are making an already stiff spring even stiffer. Basically getting a pogo effect when you hit bumps.

 

Umm.. Thats generally not good.

 

Well I had the bump steer on the 6112s at the 0 setting. I swapped to 5100s because I had one of the 6112s go out

 

Stock Tacoma's have positive camber. Look next time you pass one. Looks ignorant and handles like crap. I set mine to -0.4

 

Exactly, I think that's why I have the bump steer.

 

Just giving my opinion. Take it for what it's worth.