Im Getting Bumpsteer Now.

[Jamescad04]

So I'm getting bump steer and haven't really realized it till i got everything dialed in and lubed up. Whats the easy fix, I'm assuming a drop pit man arm but how do I know how much to drop it?

I have an adjustable trackbar from Andy at iron man as well and I'm roughly 4 to 5 inches of lift Its a bastard lift, with 33's and Andy's adjustable arms as well.

 

[bigalpha]

You shouldn't use a drop pitman arm at only 4-5" of lift.

 

[shaggybob]

You shouldn't use a drop pitman arm at only 4-5" of lift.

Correct, if the steering is stock.

If the steering isn't stock it may be needed, may not.

Ideally the drag link and track bar will have the same angle.

 

[bigalpha]

What do you mean? At 4-5", the lift shouldnt be high enough to warrant a drop pitman arm.

 

[Jamescad04]

also running zj tierods. So how do i fix the bumpsteer? is't the drop pitman arm to change the angle of the drag link? Maybe a picture would help... I can get one after work.

 

[ChiXJeff]

What do you mean? At 4-5", the lift shouldnt be high enough to warrant a drop pitman arm.

Lift height has nothing to do with it, at least, not directly. Shaggybob is right, trackbar and draglink need to be parallel, and ideally, the same length as well. Taller lifts generally require trackbar modification, and that's what may require changes in the steering. Blindly throwing in a drop pitman arm without looking at the rest of the geometry isn't going to help him.

James, are you using the stock trackbar mounting locations?

 

[Jamescad04]

James, are you using the stock trackbar mounting locations?

Yes they are the stock mount locations.

 

[shaggybob]

What do you mean? At 4-5", the lift shouldnt be high enough to warrant a drop pitman arm.

Bump steer occurs for 2 reasons
1. When the track bar and drag link aren't at the same angle and length
2. With the stock inverted Y steering as the suspension moves the toe changes.

If the steering has been changed so that the tie rod goes from knuckle to knuckle, instead of intersecting with the drag link, then the #2 reason above is gone.

If the steering is still basically a stock set up where the tie rod attaches to the drag link, the #2 reason for bump steer above will still exist, but lowering the pitman arm to allow the drag link and track bar to follow the same angle will eliminate the #1 reason above.

The only way to entirely rid yourself of bump steer is to completely:
1. Modify your steering so that the tie rod goes between both knuckles. This will have the most dramatic improvement.
2. Match the angles and length of the track bar and drag link.

 

[Jamescad04]

These were the best I could get with my phone I don't have a regular camera.

 

[wingnutooa]

why is there a hose wrapped in your spring?

i like the track bar but i'm thinking you have the same problem i do for steering.

i'm at about 5 to 5.5 inches of lift and stock steering but my track bar relocation bracket that came with my lift actually LOWERS the axle end of the track bar.

sure it allows for more down travel but ultimately screws up the steering geometry.

i just don't have the means motive or opportunity to do anything with it right now.

 

[shaggybob]

I drew a couple of lines in photoshop to show the angles in relation to each other.

The angle is pretty close as it appears but there is an obvious difference in the length of the drag link and the track bar.

Also it's basically stock steering so as one side or the other travels up or down, the toe is going to change.

Bottom line, it's going to bump steer in this configuration every time.

Convert to a crossover style steering and most of it will go away.

Go to crossover with equal length drag link and track bar on the same angle... almost, if not all of it will go away.

I'm at work right now and don't have a drawing off hand that shows how the toe changes when the suspension moves but can post something this evening.

 

[Jamescad04]

I'm at work right now and don't have a drawing off hand that shows how the toe changes when the suspension moves but can post something this evening.

Thanks man I appreciate It, looking forward to checking that out.

 

[shaggybob]

Ok so this is a crude drawing but it gets the point across

In the top picture, A, the axle is level and both the drag link and tie rod extend to the end of the axle tubes, leaving both tires pointing straight.

In B, the Passengers side is compressed and the drag link extends to the end of the tube leaving the passenger tire straight, but the tie rod no longer reaches the end of the axle tube which will cause the drivers knuckle to turn in towards the center of the vehicle, and then of course points the drivers tire inward.

While it's more of a situation where the toe is no longer correct, it does create the bump steer problem.

In a stock style steering set up it is nearly impossible to have a drag link and track bar that are the same length since the drag link and track bar are relatively close where they mount on the frame end, but the drag link is significantly longer having to extend all the way out to the wheel.

While I didn't illustrate crossover steering, it's easy to see from this example that if the tie rod extends from knuckle to knuckle, then the relationship of the tires to each other remains constant, regardless of the position of the axle.

Bump steer can still occur in crossover steering if the track bar and drag link aren't the same length and aren't on the same angle. This happens because as the passenger side swings upward, it causes the tire to want to naturally turn towards the passenger side as the axles changes it's lateral position relative to the body. However, in crossover, it doesn't cause a change of toe but will cause both tires to follow the same path when the bump steer occurs, so if one turns to the right the other does as well, and they don't turns towards each other. If both the track bar and drag link are the same length, the axle tends not to change it's lateral relationship to the body and the drag link follows the same path track bar, which removes the bump steer, and allows the tires to remain pointed straight as the axle compresses on one side or the other.

My apologies if this seems all run together, I'm working from memory.

 

[Jamescad04]

Nope it makes sense, guess I just needed the illustration and explanation. I wasnt understanding the tie-rod part of it but I get it now. Thanks man I appreciate your time and explanation.

 

[katuah]

THANK YOU shaggybob, for the diagrams. I am one of those people who you can talk at all day and I won't get it, but show me a picture and it's all clear. A knuckle-to-knuckle tie rod setup - what you mean by "crossover"- I think that may be what I need.

Lord, more money.

 

[shaggybob]

Glad I could help

 

[49erRider]

So for somebody who is stock up front except for a new track bar, what would be the best way to go about upgrading steering, product wise? Don't want to buy twice kind of thing.

3.5" lift

 

[shaggybob]

There are plenty of good solutions out there, but from experience I can say with certainty that there is not a perfect, out of the box product.

Plenty of crossover steering kits to be had, but I'm 99% sure that none of them will leave with you an equal length trackbar and drag link, and probably none of them will leave you those 2 on the same angle, but crossover by itself is a big improvement.

I have experience with 2 systems, and have seen a 3rd in action that appears to be about the best way to go.

The first crossover system I used, and cheapest, was from Rugged Ridge. It uses tie rods ends(not heim joints) DOM tubing. I had 2 problems with it, one it ate the rubber tie rod end cups like crazy, even polyurethane replacements. Second, it left most of the components hanging pretty low and eventually led to a severely bent tie rod.

Currently I'm running the Rock Krawler X Factor Plus steering, not cheap at $399 but if you want heavy duty, this stuff fits the bill. It uses 3 heims and one tie rod end that should be easily converted to a heim if you want. It's solid 4340 not tube and shouldn't bend...ever. At least on my jeep it didn't install without modifications like removing sway bar mounts, and some trimming on the right side spring perch. Also, since it uses heims, you have to drill out the tie rod mounting holes in your knuckles to 5/8" so if you go this route, there is no going back to stock without replacing knuckles. Still doesn't have equal length trackbar and drag link. Other minor draw back is the drag link mounts under the knuckle while the tie rod is on top. It works well but there are tweaks needed.

The best system I've seen on a stock 30 is built by Rock Solid Off Road. It is not a bolt on kit, but a system that is professionally installed and made to custom lengths to match your lift and vehicle. It uses heims and DOM, and is tailor built with a custom track bar and track bar mounting system that leaves everything at the same angle and length as the drag link. This system is a no bumpsteer, zero bind system.

Personally, I'm going to end up in the middle of the last 2 setups. Rock Krawler's 4340 tie rod and drag link with the RSOR track bar and drag link locations.

There are a lot of other ways to go as well. A trip to the modified tech section and searching for steering will leave you with more options than you can imagine.

 

[wingnutooa]

EDIT:

looks like shaggy pretty well covered it...



maybe i'll work on a trackbar/crossover/high steering kit...

 

[shaggybob]

It can be done without a whole lot of trouble.

I'm fairly familiar RSOR's recipe, but I won't give it out. Most of the info is out there as public information anyway, it's all in how you apply it.