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Unread 06-19-2012, 08:41 PM   #1
Agony Wagon
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Bump steer and other questions

When I first installed my 3" lift, I had to constantly steer to keep moving in a straight line. It was recommended to me on here that I do an alignment. I did that, and it now tracks much better. Until I hit a bump. I can manage it alright. Have even gotten to where I can pretty much predict how the steering wheel is going to move before I even hit the bump. But I am pretty weary of it.

Does anything look out of whack with my steering setup? Note that I am using the stock track bar, and a relocation bracket that came with the lift kit. The kit (Skyjacker) also came with fixed LCAs. I don't know the length, but I recall them being longer than stock.

I've held off buying an adjustable track bar. The rear end is pretty stiff over bumps. My shackle angle isn't terrible but could use some improvement. I'm going to get a shackle relocation kit, which will probably add an inch or more to the rear lift height. So I figure I may as well bring it up to 4.5-5" either way, and then level out the front with some spacers.

Does it look like I need an adjustable track bar, or is something else off?
Will the track bars for 3.5-5" lifts be too long if my front is lifted only 3" (until I add the additional lift)?
Does an adjustable track bar require a body-side relocation bracket? I noticed some of them come with one, some don't.

Thanks,

bumpsteer1.jpg  
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Unread 06-19-2012, 09:25 PM   #2
whitexj98
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That relocation bracket is making your track bar unparallel to the drag link creating bump steer. Get an adjustable track bar with double scheer frame bracket and take off that axle end bracket.
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Unread 06-19-2012, 09:53 PM   #3
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The track bar relocation bracket is probably the source of the problem if all your other suspension and steering parts are good. You also need to be sure that you have correct toe-in. 0 to 1/8" toe-in for a smaller lift.

Buy a double shear track bar that comes with a new frame side bracket. Iron Rock Off Road makes a very nice one.
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Unread 06-19-2012, 09:56 PM   #4
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Parallel bars is not entirely correct, though it's often described as such. It's the plane between the mounting points that must be as near parallel as possible.

http://www.jeepforum.com/forum/f9/tr...tions-1356624/
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Unread 06-19-2012, 10:25 PM   #5
Agony Wagon
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I thought they looked mostly parallel. I realized I should have been tracing endpoint-to-endpoint on the track bar.

Quote:
Originally Posted by flying_bosun View Post
Parallel bars is not entirely correct, though it's often described as such. It's the plane between the mounting points that must be as near parallel as possible.
Is making them parallel probably "good enough," at least while on the street?

I've seen some pictures where the tie rod looks parallel to the axle. Does this matter at all? I've noticed the front end lifts/lowers when simply turning the steering wheel.
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Unread 06-20-2012, 08:44 PM   #6
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Bump steer.
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Unread 06-20-2012, 09:12 PM   #7
whitexj98
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Just like has been said, the axle bracket is creating bump steer.... you need a new track bar, anf ditch the lower bracket.
bumpsteer1.jpg  
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Unread 06-20-2012, 09:32 PM   #8
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I got that, but I have a couple other side questions up there. Thank you, though. Your picture confirms what I was thinking about how to verify parallel-ness.
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Unread 06-29-2012, 04:16 PM   #9
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Double-shear

Quote:
Originally Posted by CJ7-Tim View Post
Buy a double shear track bar that comes with a new frame side bracket. Iron Rock Off Road makes a very nice one.
The frame side bracket has 3/4" drop to it. If I get rid of my axle-side bracket when I install the longer track bar and frame-side bracket, then it still won't be parallel, will it? I know the double-shear means more durability, but I'm primarily concerned with fixing how it handles.
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Unread 06-29-2012, 06:54 PM   #10
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My IRO DS Track Bar was installed at 3.5" of lift. The steering was stock, no probelms, no bumpsteer. I now have 5.5" of lift, and still have stock steering, no problems, no bumpsteer.
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Unread 06-29-2012, 07:23 PM   #11
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Quote:
Originally Posted by Agony Wagon
I thought they looked mostly parallel. I realized I should have been tracing endpoint-to-endpoint on the track bar.

Is making them parallel probably "good enough," at least while on the street?

I've seen some pictures where the tie rod looks parallel to the axle. Does this matter at all? I've noticed the front end lifts/lowers when simply turning the steering wheel.
Sorry for the delayed reply. Parallel attachments (assuming shared plane) is what you need.

TR parallel to the axle has ZERO bearing on the issue. If the front end lifts and lowers when turning the wheel, you're not setup correctly.
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Unread 07-10-2012, 09:51 PM   #12
Agony Wagon
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Ordered the IRO 1-5" Double Shear Track Bar Kit

I installed it last night. The steering is pretty tight. Returns to center way better than it has since I got it. No bump steer as far as I can tell now! Drove it about 15 miles through town so far. Handles fine, I think. Haven't made any adjustments yet, and I haven't been able to tell how it's tracking (no smooth, straight, flat roads in these suburbs it seems), but I'm sure I'll find out once I get on the highway. I'll be certain to re-torque all the bolts before I do that, though. I took a quick look after putting it on, and the axle might not be 100% centered, but it's close enough for right now.

Shipping was pretty quick. Everything was packed well. As soon as I pulled it out of the wrapping, I noticed there was a 1" scrape where something cut through the powder coating. I'll probably just hit that with some paint (or cover it up with the manufacturer's logo sticker that came in the box). And one of the two bolts included was too short to use on either end, and just a tad too fat to fit through the axle-side bracket. I would have had to drill or Dremel the hole just a teensy bit larger. I just reused the bolt that was on the old trackbar. It's only a year old, in good shape, and grade 8, IIRC. Other than those two little things, the kit was perfect. Installation was easier than I anticipated. None of the bolts gave me any difficulty getting off, including one I put red threadlocker on last summer to hold that damn Skyjacker relocation bracket...
iro_adj_tb1.jpg  
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Unread 07-10-2012, 10:07 PM   #13
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Good stuff.

I threw a IRO double shear set up in last fall as my stock track bar was knackered, and I wanted to have future proof set up. I was 2" then, and just moved up to 5" now - adjusted it out and still have no bumpsteer and better clearance for the axle and the diff.

Because of the bend, I hung a bit under the axle before and would bang the top of the front diff cover on it off road. Now at 5" the bend is parallel to the axle, and has plenty more clearance over the differential.

Glad you put the money into a very good product. I also threw in an IRO tie rod this spring that I ordered at the same time - it's pure beef and may be getting the over the knuckle treatment soon.
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Unread 07-10-2012, 10:36 PM   #14
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I'm at about 3" or so up front. I'll probably bump that up to about 4.5" to even out when I put shackle relocation boxes in the rear to fix my shackle angle. That should just about do it for me on height, so this track bar is all I need. When shopping for track bars before, I wasn't finding any that would fit both what I had now and what I will have. Glad someone makes one that gives me options.
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Unread 07-11-2012, 08:10 AM   #15
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The reason you get bump steer when the track bar and drag link are not parallel is due to the fact that these two suspension members travel in an arc as the suspension flexes. So as either member moves through its arc, there is a horizontal component to the movement. The steeper the angle of either bar, the more the horizontal component. With the track bar at a steeper angle, when you hit a bump the track bar pushes the axle to the right further than the draglink pushes the steering arm to the right. So you will feel the steering pull to the left a bit as the two bars move up through their arc of travel. I don't understand what any of this has to do with a plane as someone mentioned but even if you have parallel steering members, when one of them is shorter than the other one you can still get bump steer due to the shorter member having a shorter horizontal movement than the longer member. This bump steer effect from unequal length bars is less pronounced than what you get when the two bars are not parallel.
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