Bump Steer Issues

[Skeld]

Ever since I did a leveling kit a year ago on my truck, I've had a lot of bump steer issues.  Or at least that's what I call it.  Basically whenever the front end hits a bump the steering wheel wobbles back and forth.  I've had the truck on stock wheels and aftermarket wheels, and two different sets of tires.  I've had it aligned twice.  It's lifted about 2" in the front by the Cognito leveling kit, and I have the Cognito UCA's.  I think it rides better than a stock truck, I just hate the steering feel at this point.  Particularly right now where I just put on my XD Buck +18 offset wheels and 275/65R20 KO2 tires.  It's really bad.  See attached video which isn't the best example but you get the idea.  On a rough road basically I can hold the wheel straight but I can feel it oscillating all the time fighting to bounce left and right. 

 

I've been told perhaps aligning with positive caster would help this, but I haven't tried it yet.

 

 

[SierraHD17]

I am tossing the BDS steering stabilizer on mine as it's not the same as stock.  It tracks a bit more than anything with my 295/60/20s.   Getting the guy that's doing the gears to install the bracket while he is under there lol.

[Skeld]

There is no frame bracket on the later trucks for a stablizer?  Do you think a stablizer would help with this more high speed wobble?

[SierraHD17]

No it went away in 2015.  It can't hurt.. puts more resistance in the centerlink 

[Grumpy Bear]

 

He has film on bump steer as well. It will make you rethink tire choices. 

[sdeeter19555]

Isn't bump steer caused by poor steering geometry and/or worn components?

The more angle components have from a lift, the more pronounced the bump steer...one reason they go to a crossover steering setup in lifted SAS trucks.

When my Dodge had this, it was a worn steering box...tires can just amplify an underlying issue.

2012 2500hd 6.0l CCSB 4wd

[Skeld]

Poor geometry I would agree with.  Just curious if all the guys in here that are leveled also can't hold on to their wheel and think it's ok.  Because there would be nothing different that way between mine and all the others.

 

Worn out, I'm skeptical.  Truck has 28,000 miles on it.  The tires look ok but hard to say, maybe these tires amplify it and the snow tires I was running it do not for whatever reason.

[SierraHD17]

Well I'm cranked on stock keys and a arms and my truck just tracks a bit different but doesn't jerk back and forth like that.  Buddies 14 is aftermarket keys and stock a arms... drives normal... my employees 16 is the same as yours with keys and a arms... also drives normal lol. So no they dont all drive like that.  

 

Mine isn't even bad enough to worry about and honestly it's just the bigger rubber causing it for me.  When I had it cranked with the factory tires on it it drove completely normal. 

[Chebbyfan]

I have the Cognito kit on my 15, with the +18 Buck wheels and 295/55/20 tires and I don't have any bumpsteer like that.  I DO have a Bilstein steering stabilizer on mine, as they didn't go away until the 16 model year trucks, but I leveled mine and did tires and wheels and alignment all in one shot.  I never drove it leveled without these tires and alignment.  The only problem I have is, mine feels really heavy on the front, but I just figure its from the tire and wheel package.

[Silverado4x4]

Bump steer is very common on larger tires as to more leverage on the steering components while hitting bumps or groves in the road.

 

When I ran 42" Super Swamper tires I had to run duel steering stabilizers or the steering wheel would jerk out of your hand hitting bumps, running duels knocked it down about 80%.

 

With the tires I had that big I was only running a single stabilizer and blew a power steering hose once due to kick back then had to go to the duel.

 

As far as your steering wheel jerking real quick like that that's not bump steer, you have something else going on there with that front end of course its hard to tell from the video of what kind of road it is without riding in your truck. Real quick bumps can do that but bump steer is say hitting a bump with the left side of the truck and the wheel wants to jerk left and so on.

[4wdriver]

When I first put +18 20in wheels and 34in mud tires mine did that as well. Not continually but for a couple seconds after hitting a bump. When I first rotated them It stopped for the most part. I just rotated back and they aren’t bad. When my tires arrived from custom offsets there was a couple weights lying in the bottom of the skid so I believe I have one wheel unbalanced. I believe a steering stabilizer would help. I wonder why they did away with it. Maybe because of steering assist not sure. I wouldn’t disagree if an alignment pro said the alignment was a factor. I can add that the steering on my 16 never has felt as good as my 02 hd that had a factory stabilizer in fact the 16 has always had a little bumpsteer and some groove tracking too. 

[Skeld]

Perhaps calling it a shimmy is a better term.  I can feel it fighting to turn the wheel back and forth even when I hold it tight to stop the wobble.  It's not a full on death wobble, though, as I have read you have to slow down to get that under control on the Super Duty trucks.

 

Thanks all for the input.

[GMC4Zee]

My truck did not have a bump steer issue till i went with larger tires (285-60-20). Now when you hit a bump it will try to jerk the wheel out of your hands. Will be going with a stabilizer soon. As for your wobble, have not experienced that but I do have to take back to dealer as the 2" of play is back. Maybe that soaks up the wobble..???

[newdude]

HD trucks haven't had a steering stabilizer since 2011. 

 

Quote

 

#PIT5052F: Steering Wheel Vibration Or Customers Looking To Add Steering Stabilizer - (Jun 14, 2016)

 

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern

Steering wheel vibration or customers looking to add steering stabilizer for the Chevrolet Silverado and GMC Sierra HD 2500/3500 models.

Note: On 2011 trucks with a vibrations felt in the steering wheel, follow published SI diagnostics. The latest version of PI0650 may be helpful in diagnosing this condition. 

Recommendation/Instructions

The 2500/3500 HD trucks are not built with a steering stabilizer. 

 

A steering stabilizer is listed in the parts catalog group 6.865 (steering linkage shock absorber) and is available, but is not intended to address vibrations or brake pulsations.

This part can be added, but is not intended to be used for a warranty repair.

 

Additional information: The 2500/3500 HD's are specifically built without a Steering Dampener Shock.

 

The explanation below can be used to give a more detailed description of how the 2500/3500 HD steering system functions, with respect to road input.

 

Steering damper's predominate influence is on large heavy impacts encountered during more extreme off road events.

 

For smaller chatter/bump surfaces, the steering damper does not see high enough rod velocity to generate resistance force. 

 

For these situations, there is more mounting bushing compression than anything else.

 

The 2011-14 model year 2500/3500 HD steering gear system features the same knuckle steering arm to pitman arm length ratio as the previous (2010 and older) HD model, but the steering gear piston diameter is larger and capable of higher pressure, which creates more viscous damping in the 2011-14 model year 2500/3500 HD steering gear than the previous (2010 and older) HD model steering gears.

 

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

 

 

[Dirtbiker]

When I first cranked my keys and added bigger tires, i got a wheel alignment at the tire shop. I had some bump steer. I took it to the dealership and they did another alignment and the bump steer disappeared. So based on my experience I believe the alignment can have an effect.