Jerky steering wheel over bumps

Bump steer will always be present to some degree in a lifted truck. The tie rod angle from the lift will knock the rack to one direction and cause the bump steer. Adding larger tires and offset will multiply the effect.

 

Agreed, and this was present to a minor degree on my previous F150s, however 75lb 35"s on a Tacoma has presented a bit more deflection than I expected. Time to correct it!

 

Tie rods level to minimise bump steer at ride height. Part of any racecar alignment. No it's not a racecar and I have no idea how to do it on a lifted truck. Should be other parts available to compensate and the lift maker should have the solution a required part of their kit. GTS Bruce

 

Get some JBA Standard High Caster Arms be done with it.

 

Not Necessarily true. This is still a decent amount of caster, and well within acceptable parameters. My first thought is caster as well but he looks to be ok. When people just throw caster at it it can also very negatively impact wheel travel capabilities if the wheel is moved too far rear word.

How are people offering solutions without even knowing the wheel/tire specs, the answer might be much easier than we think.

OP, what are your wheel/tire specs?

 

Also...
What does the top of that sheet say? Year/model?
Camber should be; 0.50-0.58, +/- 0.75.
These trucks require positive camber to compensate for suspension squat/bushing deflection while underway. You're at the far end of negative. It will also have an affect on how caster is measured.

 

what would you recommend

 

They are 285/70/17. Wheels are 17x8 +0 4.5 backspacing I think

 

these do make it easier, as long as you find an alignment tech willing to listen.

 

Bumpsteer is not correctable with caster!

Reducing rack length, dropping the rack or moving the tie rods up at the spindle will.
Now, whether parts are available or clearances will allow, are a whole other matter.

 

What he said or you could spend a whole lot of money on arms and alignments but never fix the problem.

 

Well it depends on what’s causing the negative caster, short upper control arms will cause this exact problem. When he puts his light racing upper control arms on and adds castor and corrects the a arm angle the bump steer will be gone and then how will you explain that ?

 

Negative caster? Not tracking...

 

The tie rod needs to be at the same angle as the a-arm, if your drop bracket lift did not either raise the outer tie rod or lower the rack then you will get bump steer. With the proper geometry there should be nearly no bump steer.

 

Another smart guy, too bad no one listens.

 

E range tires?

this is subjective and likely a combination of things.

my thoughts are:
- caster can help a bit when very low, but these caster readings are not extremely low. too low for me and many here, but not a total mess.
- bump steer is exacerbated by a lack of compliance, usually coming from overly stiff tires. they are too firm and don't mold to the road surface enough, thus transferring that force up through the linkage. that's why reducing psi can help by allowing more tire deformation/compliance. but, for some, E range tires take this too far... mostly folks not used to driving E tires.

but there still may be a bit more to it with a given setup.

i actually have setup my truck to increase these factors because I'm a handling and responsiveness addict, and can accommodate only so much compliance.

 

Niko,

Did you get a chance to install uca's to resolve your bump steer issue? I just put in a 2.5" Bilstein lift and I have the same issue.

Thx

 

I went and talked to the alignment shop yesterday and they said it’s the bushings or ball joint on the lower control arms

 

I have similar issues, toytec boss lift at 2 inches. 265/70/17 c rated ko2s on 0mm rims, spc UCA. Tracks straight on the hwy no problem. It's the slower speeds on crappy side streets that gives the bump steer from potholes, raised and dipped portions of the street etc.

Still have yet to find a solution.

 

Wow. Everyone that said tie rod angle is correct. Bumpsteer is caused by the tie rod angling down at rest. There used to be a kit to flip the tie rod over at the spindle so it raised the end up to be nearly level coming out of the rack. You had to drill the taper out and insert a bushing.
4" of lift is big change to the steering geometry and there will be tradeoffs that need to be either accepted or corrected.