Setting toe-in (tell me my theory is wrong)

skrelnik said:
did you measure your old drag link and track bar vs the new equipment? How did they compare.

Mine was like spot on but after the install the alignment was slightly off so I corrected it. Now I think that is the reason my track bar failed when I turned the steering wheel to the far right, while leaving a parking space.

I am going to remeasure everything tomorrow and try to figure this out. But I do agree with your theory, but my agreement isn't worth jack-sh!t since I am a beginner in this topic.
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1. Check out the Firestone Lifetime Alignment. I've used it for many years. Tire guys say to realign every 10,000 miles.
2. Does the manufacturer of your modifications have the alignment specs, which should not be needed if all you did was raise the body.
Raising a body on independent suspension will change the geometry but you have solid axles so it seems to me things ought to stay the same.
Changing tires and wheels is what will change things.
 
Toe does not cause a pull. Camber and caster causes a pull.
Either in or out they will center and wear the tire surface. Caster and camber are affected by a suspension lift.
Also measure from center of rear wheel to center of front on each side. This is a thrust angle.
Or post your actual alignment rack printout.
Somebody here will tell you what is causing it.
 
Jerry Bransford said:
So is toe-in. Install a suspension lift and you'll end up with more toe-in.
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Is this because of the negative camber, and that the "top" of the tire has now been rotated forward due to the axle's new position as a result of the lift? My explanation of the question sounds a bit convoluted, but I'll bet you can figure out what I mean enough to tell me if I'm correct, or not. ;)
 
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Squatch said:
Is this because of the negative camber, and that the "top" of the tire has now been rotated forward due to the axle's new position as a result of the lift? My explanation of the question sounds a bit convoluted, but I'll bet you can figure out what I mean enough to tell me if I'm correct, or not. ;)
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I think you nailed it. Axels move ya ? Bigger the lift
 
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Squatch said:
Is this because of the negative camber, and that the "top" of the tire has now been rotated forward due to the axle's new position as a result of the lift? My explanation of the question sounds a bit convoluted, but I'll bet you can figure out what I mean enough to tell me if I'm correct, or not. ;)
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Toe increases because of the inverse Y steering. Lift the Jeep and the drag link and tie rod angles both increase, pulling the wheels together. Toe does change if the caster changes, but not as much as a change in ride height. It is also worth noting that the toe will change a bit if you adjust the track bar and drag link. Basically, any change to the front suspension and steering requires adjusting the toe. And the toe fluctuates slightly as the suspension cycles.
 
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jjvw said:
Toe increases because of the inverse Y steering. Lift the Jeep and the drag link and tie rod angles both increase, pulling the wheels together. Toe does change if the caster changes, but not as much as a change in ride height. It is also worth noting that the toe will change a bit if you adjust the track bar and drag link. Basically, any change to the front suspension and steering requires adjusting the toe. And the toe fluctuates slightly as the suspension cycles.
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Okay, that makes sense. Thanks, @jjvw.
 
CodaMan said:
Last question, I hope, before I try your suggestion. My total toe-in is OK right now, but when it's on the rack it shows that everything is shifted to the left (right at .20, left at 0). So, wouldn't holding the steering in center position and adjusting the drag link longer move both wheels to the right equally where the total toe can be split between both sides without affecting the .20 of total.
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If everything is truly shifted left, then the front axle may not be square with the rear. As mentioned already - the total toe is set by the length of the tie rod. The drag link centers the steering wheel. Only an alignment shop will be able to tell you if one side has more toe than the other, and that's only because they can compare to the rear wheels.
 
Squatch said:
Is this because of the negative camber, and that the "top" of the tire has now been rotated forward due to the axle's new position as a result of the lift? My explanation of the question sounds a bit convoluted, but I'll bet you can figure out what I mean enough to tell me if I'm correct, or not. ;)
Click to expand...
Squatch said:
Is this because of the negative camber, and that the "top" of the tire has now been rotated forward due to the axle's new position as a result of the lift? My explanation of the question sounds a bit convoluted, but I'll bet you can figure out what I mean enough to tell me if I'm correct, or not. ;)
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Taller coil springs pull on the control arms which slightly rotates the axle which reduces the caster angle which pulls on the drag link which pulls on the inverted-Y tie-rod which pulls the fronts of the tires closer together which gives more toe-in.
 
Jerry Bransford said:
Taller coil springs pull on the control arms which slightly rotates the axle which reduces the caster angle which pulls on the drag link which pulls on the inverted-Y tie-rod which pulls the fronts of the tires closer together which gives more toe-in.
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So if I've got this right, the hip bone's connected to the thigh bone. The thigh bone's connected to the knee bone. The knee bone... :D

Thanks for the detailed 'splanation, Jerry!
 
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Squatch said:
So if I've got this right, the hip bone's connected to the thigh bone. The thigh bone's connected to the knee bone. The knee bone... :D

Thanks for the detailed 'splanation, Jerry!
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Ha your 'hip bone's connected....' response is essentially the same as were made in previous responses to that explanation. :D
 
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Jerry Bransford said:
They aren't separately adjustable like they are with an IFS. One tie-rod adjusts them both simultaneously. .30 total is what you want, or .15 per side. They would only be different if the steering was turned a little to one side.
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Ηey Jerry! Just to be clear, I have to:

Adjust (Tie-rod) the front side of my front wheels to be 1/8-1/16 closer than the rear side of my front wheels. Then re-center (drag link) my steering wheel.

If I do that the degrees of the toe are the same in each wheel, and not more on one side than the other.

Correct?
 
TJim said:
Ηey Jerry! Just to be clear, I have to:

Adjust (Tie-rod) the front side of my front wheels to be 1/8-1/16 closer than the rear side of my front wheels. Then re-center (drag link) my steering wheel.

If I do that the degrees of the toe are the same in each wheel, and not more on one side than the other.

Correct?
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Correct. They could only be unequal with separate tie rods for the left and right sides.
 
TJim said:
Ηey Jerry! Just to be clear, I have to:

Adjust (Tie-rod) the front side of my front wheels to be 1/8-1/16 closer than the rear side of my front wheels. Then re-center (drag link) my steering wheel.

If I do that the degrees of the toe are the same in each wheel, and not more on one side than the other.

Correct?
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The 1/16”-1/8” suggestion is subjective without knowing how far in front of the steering axis you are measuring. What matters is the angle, which you can still find while using this method if you know how far from the steering axis you measure, using a little bit of trigonometry.
 
SecondChanceTJ said:
The 1/16”-1/8” suggestion is subjective without knowing how far in front of the steering axis you are measuring. What matters is the angle, which you can still find while using this method if you know how far from the steering axis you measure, using a little bit of trigonometry.
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It works fine for a TJ Dana 30 or front Dana 44 that is reasonably still close to the original axle design with the factory geometry for the steering.
 
I hope that i am not stepping on Mr. Bransford's toes (and please correct me sir if i am in error in this method) what i do in my shop to check the toe-in in a "real world" scenario that takes into account the lift and any suspension geometry change is to put the jeep on level ground and place two equal height jack stands under the axle that are just high enough to permit the wheels to spin. With the wheel spinning i take a can of primer and spray a line down the centre lug of the tire on both tires and let it dry. After it is dry , i measure exactly the center height of the tire and place either a third jack stand shimmed to the centre height and spin the wheel and using a scriber braced against the jack stand, i scribe a thin line in the primer . i do this on both tires and then measure at the centre height to get my toe in numbers exactly as they would be on the road. The primer wears off very quickly . I feel this gives me my most accurate measurement without getting the alignment rack gear out of the cabinet.
 
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