Alignment w/ 4" lift on TTB

[Maniak]

These recommendations to "just get the biggest camber shims available" are not likely to do much to fix the problem... Those shims adjust the CASTER as well, and if they are not the correct size it could result in improper caster even though you might be able to dial in the camber to where it looks good.

If correctly sized and installed it does not "have to" adjust caster, but yes, you can install them to mess with caster and camber..

The "book" way to do it is to install 0° bushings on the upper balljoints, and THEN take a reading on how far off both the caster & camber are, then select an appropriate degree bushing to correct it

Its amazing how many shops don't find out where you are first.. then adjust...

FWIW, I've done all my alignments at home using fully-adjustable 2-piece bushings that do not need replacing each time a different degree is called for.

How do you check caster at home? I've been trying to figure that out for a while. I was thinking of taking it in to find out what the computer says.. then measure it myself and see what I get...

 

[srknova74]

4x4junkie, that all sound good, especially the two piece shims, however I'm racking it tomorrow to go back at it again. If I don't get good results I'm going to try those shims and doing it at home. My question is: How do you check caster at home?? And where do you get a tool to check camber??

 

[Maniak]

I just noticed, those 2 piece shims don't adjust very far (+3/4° to +1-3/4° on Down Size Trucks) ... I "think" I'm at about 2 degrees right now (4" lift with 2.5" drop brackets)..

srknova74,
When I check my camber at home I use my "husky" brand 3 ft level which is digital. It will tell me how many degrees off 0 it is.. I then use a piece of metal (square tube) that is about 15 long.. That way I can put the level against the rim and not hit the tire. When things are correct, I'm at 0 degrees.

I haven't set my camber at home yet.. Just verified it after I've done suspension work..


For caster, The only thing I could think of is to put a angle finder on the front side of my beam.. But.. I'm coming up with 1 degree.. I'm pretty sure my caster is on the low side, but thats really low which is possible as. I am getting the shopping cart affect now that the tires have a lot of miles on them.

I was thinking of getting it checked and comparing their reading to what I got.. and just adjust accordingly from then on..

~Mark

 

[4x4junkie]

If correctly sized and installed it does not "have to" adjust caster, but yes, you can install them to mess with caster and camber..

That's just it, it needs to be correctly sized. It's not very likely that "the biggest ones available" will be that correct size, which in order to have the proper camber angle, forces you to turn some of their adjustment over toward the caster angle, which may not be the proper amount for the truck to track straight-ahead. The result is the truck wanting to pull right or left while you're trying to keep it in the same lane.

How do you check caster at home? I've been trying to figure that out for a while. I was thinking of taking it in to find out what the computer says.. then measure it myself and see what I get...

I wrote this page not too long ago, I hope it'll be of some help for most people trying to get a grasp on aligning a TTB. It also explains how the geometry of the steering linkage in relation to the axle affects things like handling, and the extreme tire wear problems you sometimes see after lifting these things
http://www.therangerstation.com/Magazine/winter2008/steering_tech.htm

With the truck on level ground, the correct range for caster adjustment should be available by making sure the topside of the axle beam (where the radius arm mounts) is level with the ground. This should give you approx 5° caster angle at the knuckle using a 0° bushing. Then it's just a matter of determining if the truck pulls slightly to one side or the other whether the caster needs to be fine-tuned at all from that point (the purpose of the trip around the block).
Sure, it's not super-precise, but it doesn't need to be. Just as long as both sides are within the correct range, it'll drive fine (caster is the one alignment parameter that does not influence tire wear)


Hope that helps.



P.S., yeah, the 2-piece bushings do have slightly less range than what you can get with fixed single-piece ones. If your suspension's ride height is within limits (explained in the above article), there shouldn't be any issues getting it dialed in.

 

[Maniak]

With the truck on level ground, the correct range for caster adjustment should be available by making sure the topside of the axle beam (where the radius arm mounts) is level with the ground. This should give you approx 5° caster angle at the knuckle using a 0° bushing. Then it's just a matter of determining if the truck pulls slightly to one side or the other whether the caster needs to be fine-tuned at all from that point (the purpose of the trip around the block).
Sure, it's not super-precise, but it doesn't need to be. Just as long as both sides are within the correct range, it'll drive fine (caster is the one alignment parameter that does not influence tire wear)


Hope that helps.

When you have the top level at the ground, can you check what the angle of the front of the beam is? I can easily put an angle finder there. The top of the beam is harder to get the angle finder on. That will give me the relationship of the top to the front numbers to caster.

~Mark

 

[4x4junkie]

It's probably 90°, but I will check it just to make sure.

 

[srknova74]

Allright guys, here's the update. I racked it again on the same machine as before with me in the X and 3/4 tank of gas... I also think the springs have fully settled at this point. It had a 2.7 degree caster split and a 1.3 degree camber split and the toe was a .35 degree split. I got a 2.25 degree shim for the drivers side and played with the axle pivot adjustment on the passenger side. Now I have a 1 degree split in caster and a .4 degree split in camber and a .15 split in toe. Visually it looks like the passenger side has a little more positive camber than the drivers side (probably about 1 degree ). Truck drives nice going the road though and I'm out of time for today. This was a huge step in the right direction!! I just don't know if I want to go back in it again - it's pretty damn close. What do you guys think?? Can I get it any closer or you think that's about as good as it gets?

 

[4x4junkie]

"In spec" is as good as it gets. Unless something's bent under there, (or your suspension is sitting too high or low), having the proper bushings, there should be nothing to prevent you from obtaining the same +0.25° camber on both sides, total caster set to around 4-5° that allow the truck to track straight ahead (with as close to 0° split as will let the truck track straight), and toe set to 0° (tires parallel), to 1/8" toe-in (measured at the tire treads).
I'd get the right bushings for it and adjust it until it's in spec if tire wear is important (the camber being off will affect it).


Maniak, the front face of the beam does appear to be 90° with the top (and bottom as well). You should be at approx 4-5° caster using a 0° bushing with the front face dead-vertical.

 

[Maniak]

Maniak, the front face of the beam does appear to be 90° with the top (and bottom as well). You should be at approx 4-5° caster using a 0° bushing with the front face dead-vertical.

Thank you for getting that info.. Now I can get a better idea of where my caster is.. IIRC, I'm at 91-92 degrees.. so "in theory".. that means I'm 2-3 degrees of caster.. But I'll throw the angle finder back on it to make sure..

~Mark

 

[srknova74]

"In spec" is as good as it gets. Unless something's bent under there, (or your suspension is sitting too high or low), having the proper bushings, there should be nothing to prevent you from obtaining the same +0.25° camber on both sides, total caster set to around 4-5° that allow the truck to track straight ahead (with as close to 0° split as will let the truck track straight), and toe set to 0° (tires parallel), to 1/8" toe-in (measured at the tire treads).
I'd get the right bushings for it and adjust it until it's in spec if tire wear is important (the camber being off will affect it).

Caster - Left: 3.8 Right: 4.8 Split: 1
Camber - Left: .3 Right: .7 Split: .7
Toe - Left: .1 Right: .05 Split: .05

What do you think it should be?? What shims would you use??

 

[4x4junkie]

Caster - Left: 3.8 Right: 4.8 Split: 1
Camber - Left: .3 Right: .7 Split: .7
Toe - Left: .1 Right: .05 Split: .05

What do you think it should be?? What shims would you use??

Well, I'd have both side's camber set around .5° ... And whatever caster settings between 3-6° on each side that allow it to continue tracking straight ahead when you let go of the wheel (both of your figures are between that, if it's tracking straight, then I'd say you're OK there. If it's still pulling at all, then you'll likely need to adjust them closer so there's less split between them).

As for the shims, any of: Ingalls #594, Specialty Products #24180, Moog K8986, and Spicer 6122025 would all work for dialing it in properly (I have the Ingalls on mine).

Thank you for getting that info.. Now I can get a better idea of where my caster is.. IIRC, I'm at 91-92 degrees.. so "in theory".. that means I'm 2-3 degrees of caster.. But I'll throw the angle finder back on it to make sure..

~Mark

Also remember the bushing allows about 2° forward & backward from center, so that gives you some additional leeway for adjustments (like in case one side of your vehicle is a slight tad heavier than the other, etc.).

 

[srknova74]

4x4Junkie - been driving the x all weekend, seems ok - no pull except rutted roads. staright pavement = straight driving with no hands on the wheel.

 

[4x4junkie]

I probably wouldn't worry about it much then if it drives good. Just make sure your toe setting is good, as toe will affect your tires more than anything else.