alignment question

[chewybtc]

[MENTION=67311]chewybtc[/MENTION]

Is it only on the drivers side? Your caster is so far off on that side, yet your passenger side is in spec, even with your lift and stock UCA - Most likely because of your spacer situation

It does rub a little on the passenger side, but way worse on driver side.

It seems fine while driving, it's the slow speed turning when it rubs bad.

The stealership told me the top spacer shouldn't change the number's on the caster even when I get the longer studs and put the spacer back in.

They even said that it won't hurt the tire wear or anything the way it is now.

This is all before I even got to drive it and had no time to go back to them right away when I couldn't back out of the parking spot without bad rubbing!

They had to hear it rub, but didn't say a thing to me.

 

[JayRolla]

It seems like this thread has a great deal of knowledge about alignments so hopefully you guys can chime in.
Info:
I recently completed my frame swap on my '97. (new frame is a '99)
I have OME 3" lift with 881 front and 891 rear
285/70/17 tires on FJ 6 spoke wheels.
I put 1.25" spidertrax all around to solve the tires rubbing badly on the UCA

We couldn't get the 3 top studs of the driver side shock top plate off, so we had to cut them. (not realizing that the original studs were longer than what autozone gave us in the replacement top plate) So I had to reassemble the driver side shock without the 1/4" aluminum spacer at the top of the spring that came with the OME kit.

I took it to the dealer to get aligned and they told me the spacer shouldn't matter ( I am fixing it soon, but have to find the longer studs first)

I had very little rubbing before the frame swap (only at lock really), but after the alignment it is really bad on the limited flares towards the bottom. I can barely back up and turn my wheel at all without it grabbing the flare.

I know nothing about alignment and everything looks good except the caster on left side.

Is this what is causing the rubbing issue?

Would the top spacer not being in there have anything to do with this not being in spec like the right side?

Is this how I want the numbers to be for my lift and wheel tire combo?

Thanks guys!

Before I had my aftermarket UPC's I was only able to get about 2.5* both sides of caster. I never had any rubbing issues.

After installing the LR UCA's I was rubbing like crazy at around 2.5*. They moved the caster to around 5* pretty much as far as the tire would go forward and it helped a lot. I had to still cut the limited flare and hammer the pinch weld. I can wheel pretty well now with some light rubbing.

In your situation you need to try and push that left tire forward. If you cant you might need to get some UCA's with more caster adjustment. All vehicles are different. Someone with matching caster might not rub as where you do.

 

[chewybtc]

Before I had my aftermarket UPC's I was only able to get about 2.5* both sides of caster. I never had any rubbing issues.

After installing the LR UCA's I was rubbing like crazy at around 2.5*. They moved the caster to around 5* pretty much as far as the tire would go forward and it helped a lot. I had to still cut the limited flare and hammer the pinch weld. I can wheel pretty well now with some light rubbing.

In your situation you need to try and push that left tire forward. If you cant you might need to get some UCA's with more caster adjustment. All vehicles are different. Someone with matching caster might not rub as where you do.

Thanks for your input and what worked for you. I guess I am going to wait until I get the top spacer back in on the driver side and see if that does make any difference.

It's just weird that the alignment was great before (i actually had it checked before we started the frame swap) and now they can't get that caster on the driver side any better.

And I am assuming they would have tried at the dealership, ya know?

When you say "move the tire forward", is that the caster and should it be a higher positive number?

I also notice that if I hold the wheel so it is straight the truck will steer to the left slowly. They said they made the steering wheel straight but then why would this happen. Could this be because of the top plate missing on the driver side as well?

 

[IBallEngineer]

Thanks for your input and what worked for you. I guess I am going to wait until I get the top spacer back in on the driver side and see if that does make any difference.

It's just weird that the alignment was great before (i actually had it checked before we started the frame swap) and now they can't get that caster on the driver side any better.

And I am assuming they would have tried at the dealership, ya know?

When you say "move the tire forward", is that the caster and should it be a higher positive number?

I also notice that if I hold the wheel so it is straight the truck will steer to the left slowly. They said they made the steering wheel straight but then why would this happen. Could this be because of the top plate missing on the driver side as well?

It's not that weird that the caster changed with the frame swap, despite very close tolerances, we are talking about very small numbers here. Unfortunately it is enough to be significant in the caster angle. Added to the missing spacer, which effectively shortens the distance between the lower ball joint and the frame, and you are where you are.

Centering the steering wheel has no effect on pull or drift. You are drifting the left because a vehicle will always drift to the the side with the "LEAST" positive caster. Since you are almost at 0, i'm surprised it isn't a more significant pull.

When JayRolla says "move the tire forward", he means move the lower ball joint forward, which creates a more positive caster angle as the lower part of the wheel goes forward. For 2 degrees we may be talking 3/16" or 1/4" at the center point, certainly not an inch. This may be all you need.

Don't assume the dealership tried all that hard, get your spacer in, have it checked and stress the importance of getting the caster right!

:rain:

 

[chewybtc]

Finally got the left side fixed

I ended up getting new OME 883 heavy coils (for the new AOR bumper) and taking my spacers out.

What a difference! We were able to get everything installed and then my buddy put it on the alignment machine.

He was a little confused what SAI, Included Angle, and Cross SAI were since in his 8 years of working on this machine, he has never seen them come up.

I've attached the print out and I think it looks pretty good. No more rubbing anywhere and it flexes pretty nice!

I have to go back this week to get the steering wheel straight, it's off to the left a little, so when I hold it straight the truck veers to the right a bit. My buddy is going to put it back on the machine and fix it, but I wanted to see if anyone could chime in on what those SAI things are and if we need to worry about it.

Thanks again guys!

 

[chewybtc]

Forgot to put the other pictures

Stainless skid plate is coming, but I think it flexes pretty good!

 

[IBallEngineer]

I ended up getting new OME 883 heavy coils (for the new AOR bumper) and taking my spacers out.

What a difference! We were able to get everything installed and then my buddy put it on the alignment machine.

He was a little confused what SAI, Included Angle, and Cross SAI were since in his 8 years of working on this machine, he has never seen them come up.

I've attached the print out and I think it looks pretty good. No more rubbing anywhere and it flexes pretty nice!

I have to go back this week to get the steering wheel straight, it's off to the left a little, so when I hold it straight the truck veers to the right a bit. My buddy is going to put it back on the machine and fix it, but I wanted to see if anyone could chime in on what those SAI things are and if we need to worry about it.

Thanks again guys!

8 years and he doesn't know what SAI is? OMDog!

OK, so SAI is Steering Axis Inclination. It is measured as the angle of the line drawn between the upper and lower (steering) pivot points. In the case of the 3rd Gen it is the upper and lower ball joints. The same as Caster, only this is LOOKING FROM THE FRONT. Included angle is the same measurement + or - the Camber Angle. Cross measurements are generally the side to side difference. Here is a link to a picture that shows SAI and included Angle.

http://www.grahamhathawayracing.com/assets/images/image9.jpg

The reason your SAI is so much lower is the change in angle with the taller coils, I think. I would think the spindle height would have limited that, never really looked at that. As you push the lower control arm away from the frame the spindle pulls the upper control arm down. This puts the lower pivot point closer to the center of the vehicle, effectively making the angle less.

SAI helps to center your steering and helps to offset the effects of - scrub radius, which I won't go in to here.

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