Bump Steer

[TheBigSgt]

Working for Dodge as I have, I've noticed a little bump steer in the front. OK I call it bump steer, hit a bump and the front shakes a little, on some 4x4's. Now mine was OK, but when I put a BDS 2 inch puck in it, I got some bad bump steer and even death wopple, this is when the front end starts to shake uncontrolably. This really made me mad. At the same time, we were working on this at the dealership for another customer. For him we had ordered a Super Lift Dual steering stabilizer. This cost us $200 at our cost. I thought that was alott for a couple of shocks and some clamps! Plus you had to cut grind and drill to put it on. The tech that got stuck with the job thought is was bad and so did I. I called around to several manufactures I know and to some 4x4 shops to see if there was anything out there. Basicly, nothing but Super Lift and Sky Jacker. Skyjacker also is a sponser of UROC which I announce for. Anyway, I talked with the techs there and they said they have one and it was easy to put on. I thing we only had to drill one hole for it. Looks good and the easiest to put on that I was able to find. Now I don't have any shake in the fron and it drives better than new. I'mm now running TOYO Open Country ATs 325 70 17s on HALO wheels. And it rides great. Thanks Toyo!

 

[JHardwick]

Working for Dodge as I have, I've noticed a little bump steer in the front. OK I call it bump steer, hit a bump and the front shakes a little, on some 4x4's.

bump steer is the amount on toe in/out change during the full travel in bump and rebound

 

[BStoecker]

I am getting bump steer and deathwobble on a STOCK truck. The dealer just says that this is "the normal ride for a a pickup" and that "there is no problem to correct. " This is 2-3 days after I almost put the truck in the ditch after a case of deathwobble. If I air the tires up to max pressure, they seem to do better, but lower the air pressure and watch out. I think it's time to go to an alignment shop that knows what they are talking about...

 

[DPelletier]

I am getting bump steer and deathwobble on a STOCK truck. The dealer just says that this is "the normal ride for a a pickup" and that "there is no problem to correct. " This is 2-3 days after I almost put the truck in the ditch after a case of deathwobble. If I air the tires up to max pressure, they seem to do better, but lower the air pressure and watch out. I think it's time to go to an alignment shop that knows what they are talking about...

Your exactly right. No steering stabilizer, new front end components, high end tires, shocks or a change in air pressure is going to solve the ROOT problem of DW. It is a geometric problem and is related to improper (likely not enough positive) caster adjustment. Way too many people post that thier new tires, or ball joints or whatever have "fixed" thier DW and the poor people reading this don't get the right information. Those fixes are only temporary bandaids on the underlying causes of DW and it WILL rear its ugly head as soon as something else changes or wears out.

The VAST MAJORITY of trucks that experience DW have a lift kit; 2" front leveling kit and/or larger tires. Coincidence? I don't think so.



I think the best advice is to go to an experienced alignment shop and have the settings set to a proper setting (not the 2 - 3 deg. variance recommended by DC). Most dealerships are simply not set up (and don't have the personnel with the appropriate training) to properly align vehicles. My local dealer sends all thier alignments to a local specialty shop.



Dave



ps. the Jeep guys have been dealing with this since the introduction of the TJ.

 

[BStoecker]

Your exactly right. No steering stabilizer, new front end components, high end tires, shocks or a change in air pressure is going to solve the ROOT problem of DW. It is a geometric problem and is related to improper (likely not enough positive) caster adjustment. Way too many people post that thier new tires, or ball joints or whatever have "fixed" thier DW and the poor people reading this don't get the right information. Those fixes are only temporary bandaids on the underlying causes of DW and it WILL rear its ugly head as soon as something else changes or wears out.

The VAST MAJORITY of trucks that experience DW have a lift kit; 2" front leveling kit and/or larger tires. Coincidence? I don't think so.



I think the best advice is to go to an experienced alignment shop and have the settings set to a proper setting (not the 2 - 3 deg. variance recommended by DC). Most dealerships are simply not set up (and don't have the personnel with the appropriate training) to properly align vehicles. My local dealer sends all thier alignments to a local specialty shop.



Dave



ps. the Jeep guys have been dealing with this since the introduction of the TJ.

Right on the money. Most dealers do not understand or won't admit that something is wrong if you experience deathwobble. I have been big into Jeeps for about 4 years now and this is very common on lifted or older Jeeps with a lot of worn suspension components. The dealer will almost always just say it needs a new steering stabilizer to "fix" the issue. That doesn't fix anything. If everything is set properly, a steering stabilizer is not even needed. All it does is mask the problem until it causes major problems at really bad times. I hate to go pay for something at a specialty shop that is covered under warranty, but at least it will actually get fixed there. At least it is the same shop that my dealer sends their alignment work to as well.



I had DW on a stock '98 5. 9 Grand Cherokee that turned out to be nothing more than a tire out of balance. It would hit a pothole and just go apesh*t all over the road.

 

[Punkineater]

Steering stabilizers only hide the problem... ... it's still there. Even a mild 2" leveling kit is going to move things out of their proper alignment and the axle is aligned side to side by the track bar. By going up 2" you have effectively pulled the axle to the side fractionally. If you experience bumpsteer on a stock truck I would attribute it to alignment issues, but if you experience it with a leveling kit or higher I would lean more towards the position of the axle itself.

 

[BStoecker]

Steering stabilizers only hide the problem... ... it's still there. Even a mild 2" leveling kit is going to move things out of their proper alignment and the axle is aligned side to side by the track bar. By going up 2" you have effectively pulled the axle to the side fractionally. If you experience bumpsteer on a stock truck I would attribute it to alignment issues, but if you experience it with a leveling kit or higher I would lean more towards the position of the axle itself.

I learned very quickly that whenever I changed any suspension geometry on my Jeep the next step was a trip to the alignment guys. Always worth the $65 I paid them every time. Even at 8" of lift now it still drives straight...

 

[realsquash]

Bump steer on a straight front axle truck like these (the 4x4, which is what we're talking about here) is nil stock. The higher you lift the truck the more bump steer there will be but it's negligible even at 2" over stock. Bump steer is when you go over a bump and the wheels steer with no input from the steering wheel.



As others have said it's the caster that's causing your death wobble and you can't fix it without having adjustable-length control arms. At least on mine they are stamped steel and can't be adjusted.



A steering alignment will do nothing but recenter your steering wheel after lifting the Dodge.



Andy

EDIT: I just went out and looked again and it looks like the LCA's *are* adjustable. There are indexing marks on there but it's frigging cold out so I didn't figure out how to adjust it. It's an "eccentric" looking deal and it has indexing marks and all. The service manual surely tells. I bet it's adjustable enough for a 2" lift but probably not much more.

 

[JeepinDoug]

Agreed with Punkineater, a stabilizer is a bandaid. Just like motorcyles, dirt or street, if your steering geometery is not set properly all hell will break loose and a stabilizer is just waiting to fail or be overcome.

Bumpsteer is when the draglink is at such a severe angle that when the suspension cycles upward the steering turns right/left depending on the tire cycling up, the opposite when cycling down. Bumpsteer could be just annoying or down rght deadly depending on the spring rate and draglink angle.

Death wobble could be numberous things but to fix it you need to start with the most obvious, proper geometery. When you change the lift your changing the caster angle, the biggest DW culprit. Toe in, and camber angle will not change alot from a small lift. Worn ball-studs and ball-joints would be the next things to check after wheel balance.

In the Jeep world I've set quite a few front axles, age of the rig never meant anything. As long as you know your geometery angles and have a good way to check them you should have no problems.

 

[muchsnow]

I am getting bump steer and deathwobble on a STOCK truck. The dealer just says that this is "the normal ride for a a pickup" and that "there is no problem to correct. " This is 2-3 days after I almost put the truck in the ditch after a case of deathwobble. If I air the tires up to max pressure, they seem to do better, but lower the air pressure and watch out. I think it's time to go to an alignment shop that knows what they are talking about...

https://www.turbodieselregister.com/forums/showthread.php?t=114584

 

[y-knot]

I like the Skyjacker dual In-line steering stabilizer, it sells in the low one hundreds and bolts right up without any drilling or modifications. The In-line configuration seems to result in a better feel and control, compared to the conventional dual steering stabilizer where the shocks are stacked on top each other and to the one side.