trackbar angles? what did i do wrong

Okay from all that i know and have read, the trackbar and draglink should be as close to parallel as possible to eliminate bumpsteer, so having very little when i started this project i was hoping to eliminate all the bumpsteer. It got worse. the following pic is the new setup. the major problem at this point acts more like torque steer, i hit the gas the Jeep goes left, hit the brakes the Jeep goes right. the previous setup was running a RE trackbar in the RE HD bracket and the stock location on the axle. anyway here's the new setup.



Any ideas?

Dingo

At the frame end they don't appear parallel. A drop pitman arm might cure it.

Lawn Cher' said:

At the frame end they don't appear parallel. A drop pitman arm might cure it.

Click to expand...

Or lower the trac bar frame mount about an inch.

Dirk Pitt said:

Or lower the trac bar frame mount about an inch.

Click to expand...

Frame end? or the axle end. i was thinking about drilling a new hole to lower the axle end of the trackbar, but i want to make sure before i drill.

something else had to have changed -- as close as those angles are, you shouldn't be able to notice any bumpsteer. depending on how much your front end lifts and dives, what you're describing wouldn't be bumpsteer anyway though.

Dingo509 said:

Frame end? or the axle end. i was thinking about drilling a new hole to lower the axle end of the trackbar, but i want to make sure before i drill.

Click to expand...

Axle end.

The angles are close enough that it shouldn't matter.
I'd say that your problem is due the the fact that your DL is now way longer than your TB.

Paul

Paul S said:

The angles are close enough that it shouldn't matter.
I'd say that your problem is due the the fact that your DL is now way longer than your TB.

Paul

Click to expand...

What? Are you looking at the same picture as the rest of us?

Lawn Cher' said:

What? Are you looking at the same picture as the rest of us?

Click to expand...

Yes, why?

Paul

Do you still have the OEM short arm frame mounts?

I ask, because anything over about 4.5" on OEM frame mounts and the associated steep control arm angles, induce axle steer. In other words, when the Jeep leans one way or the other from cornering or from engine torque, the steep control arm angles force one side of the axle forward, and the other side backward. causing the axle to steer the vehicle without you turnign the wheel.

Does that make sense?

CRASH

Paul S said:

Yes, why?

Paul

Click to expand...

I must be losing my mind... when I first read your response I thought you said the DL was way shorter than the TB.

Lawn Cher' said:

I must be losing my mind... when I first read your response I thought you said the DL was way shorter than the TB.

Click to expand...

No, you're just dumb.

Commonly confused with insanity.

CRASH

Lawn Cher' said:

I must be losing my mind...

Click to expand...

how do you lose something you don't have ?

red91inWA said:

how do you lose something you don't have ?

Click to expand...

If you don't have it, it is lost. If you never had it to begin with, then you can't lose it.

Lawn Cher' said:

I must be losing my mind... when I first read your response I thought you said the DL was way shorter than the TB.

Click to expand...

Had you quoted my post, you might not look as nuts as you now appear to be, I'll leave it at that :laugh3:

Paul

CRASH said:

Do you still have the OEM short arm frame mounts?

I ask, because anything over about 4.5" on OEM frame mounts and the associated steep control arm angles, induce axle steer. In other words, when the Jeep leans one way or the other from cornering or from engine torque, the steep control arm angles force one side of the axle forward, and the other side backward. causing the axle to steer the vehicle without you turnign the wheel.

Does that make sense?

CRASH

Click to expand...

Make sense, And no. I just completed the 4-link long arm. Basically copied the FT kit, however my upper arms almost parallel to the ground. I think this is because the brackets on the axle are 2" higher and im running some very soft 6" coils. so i don't think that im at a true 6" of lift as far as the geometry is concerned. also you can see in the pic the axle is kinda tilted back/ pinion down. im not sure if this make alot of difference or not. I have a camera here so if anywant needs more pics of anything just let me know and i can get them.

Also this is not will all the weight on the front yet. i need to attach the header panel, grill guard (custom 4x4 fab) and the winch. im in the process of putting the front end on it now.

Dingo

Lawn Cher' said:

If you don't have it, it is lost. If you never had it to begin with, then you can't lose it.

Click to expand...

gotcha

CRASH said:

Do you still have the OEM short arm frame mounts?

I ask, because anything over about 4.5" on OEM frame mounts and the associated steep control arm angles, induce axle steer. In other words, when the Jeep leans one way or the other from cornering or from engine torque, the steep control arm angles force one side of the axle forward, and the other side backward. causing the axle to steer the vehicle without you turnign the wheel.

Does that make sense?
CRASH

Click to expand...

Dingo509 said:

Make sense, And no. I just completed the 4-link long arm. Basically copied the FT kit, however my upper arms almost parallel to the ground. I think this is because the brackets on the axle are 2" higher and im running some very soft 6" coils. so i don't think that im at a true 6" of lift as far as the geometry is concerned. also you can see in the pic the axle is kinda tilted back/ pinion down. im not sure if this make alot of difference or not. I have a camera here so if anywant needs more pics of anything just let me know and i can get them.

Also this is not will all the weight on the front yet. i need to attach the header panel, grill guard (custom 4x4 fab) and the winch. im in the process of putting the front end on it now.

Dingo

Click to expand...

Steep control arm angles can contribute axle steer, but only if there is body roll involved. Braking and accelerating in a straight line shouldn't induce enough body roll to make a difference. Plus, you have replaced the steep arms of the stock design with your longer and more horizontal Full Traction copy.

Your bump steer is coming from the difference in length between the track bar and the drag link. Keeping these parallel makes sense when they are the same length, but with your setup, the Jeep would steer better (reduced bump steer) if your track bar was at a steeper angle than the drag link. In your case, it's just the opposite.

Try lowering the track bar mount on the axle end by around an inch or so. The steeper angle on the track bar will increase the lateral movement under dive to more closely match the drag link. Added drop at the Pitman arm would have a similar effect, but will also increase the possibility of cracking your frame where the steering box mounts.

Adding to this, the change in your control arm angles lessens the anti-dive percentage. Lowering the anti-dive improves ride and may help to keep the front end from unloading on steep climbs, but it allows more dive under braking. This plus the soft springs are increasing the vertical suspension movement under braking, exagerating the bump steer even more. Therefore, some stiffer springs will also help.