Ok folks I have a question that is very common terminology in this forum. What do you define bump steer as? What it happens and what it feels like when it does happen. WOL I would love to here from you on this also Planman. Thank All

 

Well, I'm no planman but,

bumpsteer is when the tire direction moves because of the force of hitting a bump. The steering linkage (and tires) should move when you move the steering wheel not from the force of hitting something with the tires.

 

LOL you don't need to be planman to post I would just like to here from the also.

 

Hitting a BUMP makes your STEERing wheel (and your vehicle) move ... that's BUMP STEER.

 

I know you think it's that simple but I got some info from a very reputable lift company saying it's not, I want to know what a bump steer is from an experienced person. Please no smart comment I'm not a idiot I know what my jeep is doing I was just told it's not bump steer!

 

You can also have a bump steer feeling when your jeep is actually doglegging (torsional twisting). This is very evident if you lift your jeep and do not center the axles or use drop brackets. After lifting, the front and rear both are torsioned towards the side of the jeep that the track bar attaches to the frame. As you know the track bars mount points are on different sides of the jeep in the front vs. the rear. I had this bumpsteer feeling after I put on the RC budget boost. It felt like the front and rear of the jeep would go in differing directions on a moderate to severe bump. Althought not technically bump steer, it is a similar feeling except for no real affect in the steering wheel.

To correct, I put on adjustable track bars which recentered the axels and took out most of the torsioning affect. Without brackets to reposition the track bar mount points, you will have more torsion with a lifted jeep due to the different geometry of the track bars vs. stock.

The other, more prominent cause is a lifted jeep having the front track bar and the drag link not on the same basic plane. With much lift at all, the planes are quite different. If the front compresses in a bump, the track bar travels one distance and the drag link travels a different distance. This then forces the drag link to affect the wheels the amount of the differing distance. see image below. Drop brackets on the track bar, drop pitman arm, or both are used to correct this issue.

 

I have experienced it. I tried to run a drop pitman arm without a drop trackbar bracket ... My JK would have Bump Steer running over a Quarter ... and just about any bump would throw it into death wobble.

Bump Steer is caused by bad front suspension Geometry ...

 

Thank you rubired that is a great description of torsional twist! And a very insightful explanation, I have a rear track bar bracket as well as a aftermarket front track bar so I don't have those issues, what I do have is a jerk when I go over bumps in the road or hit a dip. I was told there is no way I have bump steer.

 

Mine doesn't have problems with DW anymore but when I hit a bump it will do what I called bump steer, I was told very adamantly that I can't have bump steer over and over again because I have the right steering geometry. I have a 3.5 inch lift with a front track bar that is adjustable. It is set up the manufactures specks and is tight. What do I have?

 

Do you think maybe your steering damper may have given out and what you feel now used to be masked by the damper. Assuming they are correct about your geometry.
Funny how somebody can tell you what they think you have / should have vs. what you know and are actually experiencing. That would be frustrating!
Just a thought