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Bump Steer

Skeld

By Skeld
in Modifications & Accessories

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Skeld Enthusiast

Skeld

Posted
Posted

I'm leveled with a Cognito kit with upper control arms. I get quite a bit of bump steer now compared to stock. Nature of the beast or what can I do about it?

 

Also I get some clunking if I'm driving over rocks or little bumps while turning at slow speed.

Skeld Enthusiast

Skeld

Posted
  • Author
Posted
Silver16, on 29 Jun 2017 - 4:45 PM, said:

Upper control arm?

 

Cognito offers an aftermarket upper control arm as part of their kit.

Dirtbiker Enthusiast

Dirtbiker

Posted
Posted

I cranked my torsion bars 1 3/4 inches. Got a wheel alignment at kal tire. It had a lot of bump steer and seemed to pull to the rght a little. Got another alignment at the dealer and the bump steer went away. It seems the wheel alignment is critical.

Skeld Enthusiast

Skeld

Posted
  • Author
Posted

I cranked my torsion bars 1 3/4 inches. Got a wheel alignment at kal tire. It had a lot of bump steer and seemed to pull to the rght a little. Got another alignment at the dealer and the bump steer went away. It seems the wheel alignment is critical.

 

Ok, good to know. Maybe I'll give the alignment another run. It was atrocious before the alignment and after the level. Got a lot better after being aligned but still not as good as it originally was.

MW2500HD Enthusiast

MW2500HD

Posted
Posted

I'm leveled with a Cognito kit with upper control arms. I get quite a bit of bump steer now compared to stock. Nature of the beast or what can I do about it?

 

Also I get some clunking if I'm driving over rocks or little bumps while turning at slow speed.

Get another alignment by a good shop that knows what they are doing and not going to factory specs. Depending on the crowns of your roads and where you mainly drive I would do about 4 degrees caster with a 1 degree split. So example would be drivers side 4.0 and passenger side 3.0 as a starting point. Cognito recommends that. PM me if you need more details and specs. Took me four times with a good shop to get a decent alignment. It's trial and error sometimes.
Dale L Enthusiast

Dale L

Posted
Posted

I would do about 4 degrees caster with a 1 degree split. So example would be drivers side 4.0 and passenger side 3.0 as a starting point.

 

 

 

Why the difference between driver and passenger sides?

Skeld Enthusiast

Skeld

Posted
  • Author
Posted

Get another alignment by a good shop that knows what they are doing and not going to factory specs. Depending on the crowns of your roads and where you mainly drive I would do about 4 degrees caster with a 1 degree split. So example would be drivers side 4.0 and passenger side 3.0 as a starting point. Cognito recommends that. PM me if you need more details and specs. Took me four times with a good shop to get a decent alignment. It's trial and error sometimes.

 

I brought it to a Chevy dealer. I assume they are trying to align to the wrong specs then, or will their machine guide them in the right direction even though the suspension is not the same as OEM? I have no idea how alignments work.

SMiller Senior Enthusiast

SMiller

Posted
Posted

 

I brought it to a Chevy dealer. I assume they are trying to align to the wrong specs then, or will their machine guide them in the right direction even though the suspension is not the same as OEM? I have no idea how alignments work.

Fact is it takes a good allingment tech that has leveled and allinged a lot of trucks to do it right, today's idiots can only read a screen and do what the computer tells them. Took me 3 times at pep boys to give up, went to the local GMC dealer and they had a tech that knew his GM trucks and had leveled a ton of HD trucks, knocked it out in 20min. and it's perfect.

MW2500HD Enthusiast

MW2500HD

Posted
Posted

Why the difference between driver and passenger sides?

For road crown, most roads are crowned to the right. The truck will pull to the side with the lower caster. I beilive factory cross caster is .5-1.0 as an example.

MW2500HD Enthusiast

MW2500HD

Posted
Posted

Fact is it takes a good allingment tech that has leveled and allinged a lot of trucks to do it right, today's idiots can only read a screen and do what the computer tells them. Took me 3 times at pep boys to give up, went to the local GMC dealer and they had a tech that knew his GM trucks and had leveled a ton of HD trucks, knocked it out in 20min. and it's perfect.

SMiller is correct that you need a tech that understands what camber and caster do. Most techs at dealerships will just go to factory specs looking a the computer read out screen and put it in the green and call it good. I have a good guy at les schawb that's been doing alignments 25+ years and understands what's going on. I'm no expert myself but understand the affects of toe in caster and camber. Do you have a print out from the dealer for your current alingment specs?

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