SinisterGrin
New member
Anyone having any issues with bump steer? Any solutions?
Thanks!
Thanks!
Bump Steer
- Thread starter SinisterGrin
- Start date
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Are your suspension bushings worn? Are you ball joints worn? If so, that's gonna cause directional control problems.
Are you lifted? Stock height?
If you're lifted, do the following:
Aftermarket front upper control arms by JBA or SPC to correct Caster. Upgraded rear lower and upper arms to make the rear suspension track better. Install Poly steering rack bushings. I'd recommend Whiteline for those. Longer sway bar end links: Put the stock front end links in the rear and buy some 2nd Gen 4Runner rear end links for the front. You could also get poly sway bar bushings as well.
That's my advice.
jross20
New member
Do you know what your caster looks like? If I'm not mistaken, I think a very high caster can cause bump steer. Of course you don't want it to be too low!
shadow247
New member
I have run as high as 4.2 degrees of Caster on my 3rd gen. It was absolutely FANTASTIC for street use, but I lost a bit of turning radius on the trails.
I'm back around 3.2 degrees and its not nearly as tight.. I would like to get up closer to 3.8 to 4.0 degrees of caster.
Rushthezeppelin
New member
Is it clearly coming from the front? I know that lift in the back without a panhard bracket can do odd things with the steering too. Something to think about.
jross20
New member
I don't know the exact amount, but I'm pretty sure the higher the caster the higher the chance for bump-steer due to the geometry.
Also, I've been told by a couple of guys that by running a higher value, it makes the steering more difficult and thus might potentially put too much stress onto the steering rack. No idea if what is "too much" though... I just wanted to share.
More Caster slows down the steering. It reduces bump steer. It's also responsible for the "Return to Center" when you let go of the steering wheel. There is a sweet spot of the amount of Caster for steering ease, straight line stability and overall steering feel.
I have mine set to 3.5*.
You’ve got that backwards. More caster helps diminish bump steer and helps the steering wheel center faster/firmer. More caster increases the effort it takes to turn the steering wheel though so it is a balancing act.
jross20
New member
Actually, now that I've slept on it I think that we're both correct.
Very low caster means that you can get bump steer from the front of the wheel, whereas very high caster causes bump steer from beneath the wheel. So I think you want to be in the middle, now what that middle value is I have no idea... Haha
That's not how that works...
jross20
New member
If your caster is very high (again I don't know the exact amount), bumps from below the wheel will push the wheel "up" and as such turn the steering wheel.
I mean it might be something like crazy high that we would never achieve on our trucks so maybe it doesn't matter.
I could draw it out in MS paint if you wanted, though my art skills suck...haha.
Edit: Thinking about it further it might not actually be referred to as "bump steer" with very high caster but to me it's all the same. Some kind of bump causing the steering wheel to turn unexpectedly.
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A MS paint drawing of your theory won't prove anything. Find some sort of reputable source with evidence if you really want to argue this with me, but until then I'm going to rely on my ASE certification, training, and job experience on this one. I'm not trying to be a dick about it, but you're theorizing false information on the internet.
Edit for spelling.
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Gerdo
New member
Please Explain what you are considering bump steer.
I had a lot of wandering, especially on road undulations. It was due to most of the front control arm bushings being worn out.
I have also has a swimming feeling when I first lifted my 4runner due the the rear panhard bar still being in the stock location. When the vehicle (rear especially) would compress on bumps, the axle would move in an arc side to side (diagonally due to the bar not being flat). Getting the panhard bar flat keeps the axle more centered thru it’s normal travel.
I have also had a loose feeling (and oversteer) from too soft of rear shocks. This too will will cause a swimming feeling in the back as the axle goes up and down thru the arc a few times on bumps.
If you have lifted the vehicle, this changes the geometry in the rear suspension and will increase oversteer.
I had a lot of wandering, especially on road undulations. It was due to most of the front control arm bushings being worn out.
I have also has a swimming feeling when I first lifted my 4runner due the the rear panhard bar still being in the stock location. When the vehicle (rear especially) would compress on bumps, the axle would move in an arc side to side (diagonally due to the bar not being flat). Getting the panhard bar flat keeps the axle more centered thru it’s normal travel.
I have also had a loose feeling (and oversteer) from too soft of rear shocks. This too will will cause a swimming feeling in the back as the axle goes up and down thru the arc a few times on bumps.
If you have lifted the vehicle, this changes the geometry in the rear suspension and will increase oversteer.