Darting front end, suicide straight axle

[21willys]

My front seams to be real darty at times on uneven roads. Do I need to adjust the front of the tires closer together or further apart? Or am I thinking completly wrong? I have the front end set at real close to 7 degrees.

I tried the search but it won't work with my iPhone for some reason.

 

[dmw56]

Sounds like bump steer. Do you have a traditional side steer set up?

 

[21willys]

I don't believe it's bump steer. Bumps don't bother it. It's when the road is uneven it will dart around without the suspension even moving. I can see the whole drivers side of the suspension.

It is traditional steering. I will get a pic as soon as I make it to the garage.

 

[Bonehead]

Post a picture of what you are running, and how it is set up.

 

[Sam_Fear]

Sure it you have the toe right? Toed out will make it do that.

 

[21willys]

Sure it you have the toe right? Toed out will make it do that.

That's what I was asking. I knew one way or the other would make it do that. Didn't know witch way tho.

 

[Torch]

i usuall set my toe in at about 1/8" inch. if I have any wear in the front end i try to compensate. the tires will always toe out when driving to take up the slack so you want to measure your toe with slight pressure between the fronts of the tires to take up any slack.

if your caster is set right then a line drawn through your kingpin intersects the ground in front of the center of the tires contact patch.
by the friction of the road the tires are drawn to follow the kingpin. if your caster is set with the kingpins tilted backwards then the contact patch will be out ahead of the kingpin centerline/road intersection. this makes the steering easier because the kingpin is now pushing the tire not dragging it behind and any irregularities in the road help to power the steering but makes it twitchy.

toe out causes one tire to run true and the other to grab the road at an angle in front of the kingpin, excessive toe in grabs the road behind the kingpin and doesnt feel as twitchy but eats the tires just the same

 

[Sam_Fear]

I thought you meant your caster was set at 7 degrees.

Measure 1/2 way up your tire tread in the front, rotate the tires 1/2 turn and measure the same marks in the back - should be about 1/8" shorter in the front. Go from there. If it's twitchy, give it a little more toe in, and check again.

Like T-mann said, caster angle can affect it too. Even changing your front or rear ride height a lot can change caster enough to make it noticeable in the steering.

 

[21willys]

Yes caster is at 7 degrees. The toe is what I believe where my problem started. I adjusted the toe inward by one and a half turns on the hiem joint and drove it. This time I got some wobble at a low speed. But the darting around wasn't near as bad. I will take some measurements and report back.

Photo bucket won't load for some reason. I will load pictures as soon as it does.

 

[21willys]

I will add that everything on the front end is new.

 

[donsrods]

The pictures are really important, otherwise all you will get are guesses.

Don

 

[21willys]

Hope that helps. And the help is appreciated!

 

[dmw56]

Not much travel on the shocks.

 

[21willys]

No the shock and headlight mounts need redone.

 

[donsrods]

I see a few things. The shocks, as mentioned, are useless. Not only too long but too far away from the axle to have any effect at all on the ride. Just the way it is sometimes with a suicide front end.

The caster looks ok, but since you have the ability to change it with those clevis ends, start experimenting. Go down to 4 and see what happens, then try going up to maybe 9 and see if there is any change.

Toe in sometimes needs to be toe out. Try setting an 1/8 or so of toe out and go for a ride.

Finally, add a SoCal $39.99 steering stabilizer to the spot I marked in red. It will make a totally different car out of it in the way it handles.

Don

 

[Dirtyrat]

Yea I thought the starting point was 1/8" out as well...

 

[Sam_Fear]

They might be onto something. Watch to see if your shocks bottom out. That would make the outside tire take sudden increased weight transfer in a turn or on uneven surface.

 

[Old Iron]

Aren't bias ply tires bad about that anyway [S

 

[Old Iron]

Looks like you have bias ply on front and radials on the rear.
Not a good combo

 

[21willys]

Thanks for the replys guys!
I will check the toe in/out tomorrow morning and try as suggested.

Don I ran the car for a few real short trips without the shocks and they do make a difference. I am going to mount them different or switch to torsion shocks tho.
I will invest in the stabilizer shock. I was considering it anyways.

Ive heard people say to not use both bias and radials before but never heard the science behind it. Anybody know? Is it just the different flex rates?

Thanks again.