What’s all this mean? Alignment specs

[56cbr600rr]

Jeep pulls slightly and slowly to the left. Before and after this alignment. 2.5 Readylift SST and 35” Duratracs.

this in spec?

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[Greg_L]

Camber is the tilt of the tires. Positive camber has the tops of the wheels tilted out further than the bottom. Vehicles pull to the side with more positive camber.

Caster is the imaginary line drawn through the upper and lower ball joints. The tilt forward or back of that line is degrees of caster. Negative caster tilts forward, positive caster tilts rearward. Vehicles pull to the side of more negative caster. Positive caster is what whips the steering wheel back to center after a turn and keeps you tracking in a straight line. We generally want positive caster at all times as drivers.

Toe is how the fronts of the tires point in or out. Like "pigeon toed" people, toe is usually slightly positive, meaning it points inward. Vehicles generally pull to the side of the least toe compared to dead straight 0.

Thrust angle is the imaginary centerline created by the rear end. It's not always the actual vehicle centerline. Vehicles tend to pull opposite the thrust angle.

From your readings I see no reason for a left pull. I'd assume it's a tire issue maybe.

 

[56cbr600rr]

So my concern is these “after” numbers are OK for my set up? And also is the variance in the toe anything to be concerned about?

 

[56cbr600rr]

Camber is the tilt of the tires. Positive camber has the tops of the wheels tilted out further than the bottom. Vehicles pull to the side with more positive camber.

Caster is the imaginary line drawn through the upper and lower ball joints. The tilt forward or back of that line is degrees of caster. Negative caster tilts forward, positive caster tilts rearward. Vehicles pull to the side of more negative caster. Positive caster is what whips the steering wheel back to center after a turn and keeps you tracking in a straight line. We generally want positive caster at all times as drivers.

Toe is how the fronts of the tires point in or out. Like "pigeon toed" people, toe is usually slightly positive, meaning it points inward. Vehicles generally pull to the side of the least toe compared to dead straight 0.

Thrust angle is the imaginary centerline created by the rear end. It's not always the actual vehicle centerline. Vehicles tend to pull opposite the thrust angle.

From your readings I see no reason for a left pull. I'd assume it's a tire issue maybe.

it did pull slightly to the left before, and after the four wheel alignment.

 

[Greg_L]

So my concern is these “after” numbers are OK for my set up? And also is the variance in the toe anything to be concerned about?

Your toe readings are within the range of human variance in how they set up the machine. Nothing to worry about.

 

[Greg_L]

it did pull slightly to the left before, and after the four wheel alignment.

Swap the front tires side to side and see what happens.

A slight left pull on flat ground is ok since it's usually to counter road crown.

 

[Commodus]

If rotating the front tires left to right doesn’t change your pull then you most likely have a problem in the steering gear and or power steering system

 

[Zachanadandy]

It probably won't help your slight pull but I would add either the longer Mopar lcas or adjustable lcas to get the caster closer to 6⁰, it will handle better as a result.

 

[NewGladdyOWNR]

Did you just put the lift on?

 

[Charles 236]

Do not worry about the toe reading on the left and right columns of your printout. The total toe is what matters here, and yours is nearly dead on.

 

[Fabtech Motorsports]

Agree, bump that up a bit for better road feel.

It probably won't help your slight pull but I would add either the longer Mopar lcas or adjustable lcas to get the caster closer to 6⁰, it will handle better as a result.

 

[Deleted member 52902]

This is way out of my knowledge base but, it would seem to me that a rear axle that is either bent or not hung square to the vehicle chassis could be the issue.

Such as the driver side wheel is slightly closer to the front end, or the passenger side is slightly back, closer to the rear of the JEEP.

I am sure your alignment process had all four tires at the appropriate pressure but something in the rear axle alignment, or rear suspension might make the difference. Could be either side or the whole "rear" or even something askew with the in the frame itself that makes a good rear axle and suspension not located the right "track". Factory goof, or some accident during the life of this JEEP.

I haven't had any vehicle aligned in years. Can a 4 wheel alignment system be used with a JEEP, to verify anything about a solid rear axles positioning, including even if parallel is correct, but offset left or right?

Just guessing all of this.

 

[Greg_L]

This is way out of my knowledge base but, it would seem to me that a rear axle that is either bent or not hung square to the vehicle chassis could be the issue.

Such as the driver side wheel is slightly closer to the front end, or the passenger side is slightly back, closer to the rear of the JEEP.

I am sure your alignment process had all four tires at the appropriate pressure but something in the rear axle alignment, or rear suspension might make the difference. Could be either side or the whole "rear" or even something askew with the in the frame itself that makes a good rear axle and suspension not located the right "track". Factory goof, or some accident during the life of this JEEP.

I haven't had any vehicle aligned in years. Can a 4 wheel alignment system be used with a JEEP, to verify anything about a solid rear axles positioning, including even if parallel is correct, but offset left or right?

Just guessing all of this.

The non-adjustable rear end sets the stage for how the front end is aligned. That's where "thrust angle" comes into play. The thrust angle is the imaginary centerline of the rear end, not necessarily the centerline of the vehicle. Thrust angle is the perpendicular longitudinal reading off the rear axle. You can't adjust anything on the rear without major surgery, so you just base the front (mainly toe settings) off what the thrust angle is. You can't do a "four wheel alignment" on a Jeep unless you've done some major modifications. Jeep alignments are front end only, based off thrust angle.

In very extreme cases, a vehicle with a bad thrust angle can still be aligned but it will "crabwalk" or "dog walk". It'll drive straight but the body will be a little off center going down the road.

 

[56cbr600rr]

Did you just put the lift on?

Year and a half ago. Was more centered driving back then.

 

[Deleted member 52902]

Thanks Greg. I imagine this doesn't help the guy with his issue but it certainly is great information for me and I suspect others to know.

Another thought - Lets say a vehicle has a moderately different diameter than the tire on the other side. The revolutions per tire in this case, could lend itself to require compensation in steering. But this scenarios isn't likely with the same brand, type, tread pattern, and labeled size are the same as well as a reasonably identical tread wear.

Wondering what the effect of one snow tire on the front axle not installed with the specified rotation direction installed backwards, might cause.

And finally, is it possible that hydraulic or electrically assisted steering could somehow be unbalanced?

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