Bumpsteer Help

[91yotaprerunner]

Im finally taking the time to sit down and reduce the bumpsteer on my truck as much as possible, cause as you can see in the pictures, its pretty bad.

My questions are

My truck toes in at full bump, and toes out at full droop, obviously the problem is really bad at bump, but not so bad at droop. What would be a ball park idea to start from as far as making changes in the steering

Moving Steering arm down?
Moving Tire Rod Inner pivots Inward, or Down?

I use stocked mounting locations for control arm pivots, but the steering has been moved foward an 1.5 inch to accomadate for the 1.5 inch that the arms move the wheel base foward.

Its a stock modified spindle, but it has been changed into a lift spindle, and the spindle was made taller than OEM.

Here are some pictures, one shows the massive amount of bumpsteer at full bump, another is the best picture i have of the moment to give you an idea of the tie rod placement with respect to the upper/lower arm, and the last one is a pic of the spindle.

Any help would be appreciated, im pretty sure that the steering arm on the spindle needs to be lowered, but if i am wrong please correct me.

Matthew

[Fourstroker]

A few things to think about. Unless you are running near equal length A-Arms and a tie rod that is the same length pivot to pivot as the A-arm you will always have to compromise. I have a few suggestions that may or may not work since I don't know that much about Toyotas but I do know a bit about steering.

Assuming that you don't have tie rods as long as your a-arms and you can't make the tie rods any longer mount your steering box, inner pivots and spindle steering arm so that the tie rod is level at the midpoint of your travel. ie if you have 20" of front travel mount all components so the tie rods are level at 10" from full droop.

Once you get it all mounted(I would mock it up and cycle it before welding anything solid) run it up to that 10" point and set the toe as dead straight or even 1/16" toed in. When you cycle up or cycle down from that point your wheels will always toe-in(believe it or not this is what you want). A toe-out condition will want to rip stuff off.

This should reduce your bumpsteer number considerably. The tie rod is making an arc as the suspension travels through the cycle so any way to make the tie rod longer will reduce the sharpness of the arc andthe bumpsteer number.

By looking at your truck it appears that the steering or inner pivot is mounted too low.

Good luck

PS Did I see your name entered in the SNORE Midnight Special...See ya there

[91yotaprerunner]

ok thanx, i can see what you are saying, the centerlink is at stock hieght, so i dont know about it being too low, but who knows.

And yes, i am entered for the SNORE Midnight Special, being i live in vegas now, and they are trying to make the 1450 class grow there, figured i would run the race.

See you there

[hoeker]

make a flat board in the area of the inner pivot, unhook the tie rod and make a "dummy" tie rod that has up to 3" of length adjustment. at ride height make the wheel straight and using a marker and your tie rod make arcs on your board adjusting the length of the rod in 1/2" increments, noting every length at the arc. now do this at 80 or 90 % compression and 80 or 90% droop. looking at the way the 3 arcs intersect will give you your best starting point for your inner pivot. i bolted 7' long angle iron to my hubs to make sure they were straight when i did this on my truck.

now, after the inner pivot is handled you need to see what the steering does as you turn the wheel, the same angle iron can be used to see if the tires stay parrallel or toe in or out as you turn. if you're way off move the outer pivot then start over on the inner location, checking in the same range of length as your best initial result.

it's a lot of work, but if you're carefull you can get perfect results!

off to crandon!

[curt]

As a quick fix, I thought the centerline of the outer tie rod needed to be on the same plane as the upper and lower ball joints when looking at the assembly from the front. Your's looks like an inch or so outside that line so it is pivoting on a different arc than the upper and lower- or at least it's not splitting the difference between the 2 arcs...Curt