New steering arm = bumpsteer

[MITCH_89']

As the old saying goes, "if it ain't broke, don't fix it". Well, Ive had a 3" Tough Country suspension under my Blazer for a while now and used my factory steering arm. The angle of my draglink was way off as you can imagine. I have never experienced ANY bumpsteer running it this way. My alignment got off a little so I was going to take it to Big 10, but first I installed raised steering arm. Now the draglink is perfectly horizontal, the truck drives straight again, but MAJOR BUMPSTEER!! I dont get it. I have an ORD steering brace, steering stabilizer. Now Im thinking Im going to have to put my old steering arm back on. Ive done a search for bumpsteer, and everyone seems to think the swaybar relocating kit fixes this. But why was it fine before???????

BLAZE IT UP!!

 

[michaelm]

how much taller is this new steering arm?
3" lift is fairly minimal
a 2" drop pitman would be closer to what i would have tried
swaybar correction suggestions are throwing good money after bad, go back to square one

 

[MITCH_89']

Im not sure what size lift the steering arm was made for, but it got my draglink straight. I asume that is how it is suposed to be.

BLAZE IT UP!!

 

[Jersey]

Mitch - if you figure this one out, let me know. I'm having the same major bumpsteer. I just installed 4" rancho lift, all new shocks, stabilizer, axles, wheels, 35's....and installed a skyjacker raised steering arm that made my draglink level and damn....she wobbles back and forth sometimes i think it's going to yank the front axle right off the ubolts! I just got it aligned and all the tie-rods and balljoints that were questionable replaced so all is good with that. I'm ordering the ORD brace and hoping that will help and was considering adding a second stabilizer but i don't want to hide the real problem. I was thinking crossover steering to because they said this also helps but that's $ and my wallets pretty thin right now with all the stuff i just did. Hope you find the answer, and it works for me also.

- Jersey

'91K5 - 350, 700R4, NP241, 14BFF/Dana44, FlowMasters, 4" & 35x14.50's on Welds
<a target="_blank" href=http://community.webshots.com/user/len1313>[/b]PICS[/b]</a>

 

[michaelm]

but you found out that is not true
I get flak for not being nicy nice on here, but i dont think blowing sunshine up your ass will get your truck working
so
what causes bump steer
- a lift spring is usually curved like a U
- when it compresses it elongates
- if the draglink it parallel to the ground at normal ride hieght, its effective length shortens when it travels either up or down
- so when the spring elongates during compression, the effective length of the draglink gets shorter, the exact opposite of what you need
-with springs that are U shaped the draglink should slope down towards the rear of the vehicle, how much is the tricky part

= now with flat or reverse curved spring like the factory ones
= as the spring compresses it shortens...you should have the idea to figure out the rest

bumpsteer is a tricky thing to reduce
as noone wants to move the box or spend any real money on it
crossover is the easiest answer

perhaps someone here knows how to do the math to make a push pull system work wityh minimal bumpsteer without moving the steering box, I have never seen the math posted anywhere but would love to see it. even race car books tell you it is a trial and error procedure on each individual chassis

 

[MITCH_89']

I think in my original post I answered my own question. I guess I need to put the factory one back on since it caused me no problems. The draglink angle is crazy, but hey, if it works then it works, right. The only thing I hope Ill have to do is adjust the dragling again to get my steering wheel straight.

BLAZE IT UP!!

 

[Triaged]

The reason people (including me) suggest a sway bar disconnect/correction is because the swaybar won't be sitting flat after the truck is lifted (it will be pointing down towards the front). Because of the angle it sits at when the suspension is compressed it forces the axle forward (causing it to bind and have the bumpsteer). You can see what kind of difference the swaybar disconnects/correction will make by disconnecting the swaybar and seeing if it still has the bumpsteer (yes it will roll more...I'm talking on stuff like dips etc...). If that helps either ditch the swaybar or get the disconnects. If that does not help try putting on the stock steering arm like 77 said.

To me the disconnects aren't throwing good money after bad, but are less work than doing a steering arm (time is what I am short on) and a upgrade that I would do sometime any way (I don't have a swaybar any way but if my truck was a daily driver I would install one).


'71 Blazer CST w/ a 400sbc, 4" lift, 36" Supper Swampers, and alot of rust
<a target="_blank" href=http://community.webshots.com/user/triaged>See it Here </a>

 

[michaelm]

adding links to the sway bar is an excellent idea
the stock method of attaching it to the axle is assinine and can only bind, never thought it would add to the bumpsteer equation though. adding another arc for the axle to try to follow certainly cant help matters
almost every sway bar needs end links to take the bind out of the equation
chevs method there helps you when you break the centre pins though
anyone that can weld could make a set of end links in a few minutes for a lifted truck, my springs are so stiff that i didnt notice a difference without the bar

 

[Triaged]

That is a good point about the swaybar helping the center pins. On 1st gen blazers there was a recall to add a plate in front of the driver side spring eye in case that bolt should break you would still have some semblance of steering. Maybe the swaybar was added in '73 to solve this (along with many other reasons).

'71 Blazer CST w/ a 400sbc, 4" lift, 36" Supper Swampers, and alot of rust
<a target="_blank" href=http://community.webshots.com/user/triaged>See it Here </a>