What’s all this mean? Alignment specs

[Greg_L]

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.

Define "moderately". Different sized tires L vs R will absolutely affect steering, feel, alignment, etc. The car will pull to the side with the smaller tire. Different tire sizes is never a good idea. I don't know what the limit is. I guess that would depend on lots of variables.

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

A directional tire rolling in the wrong direction won't necessarily affect a vehicle "pulling" one side or the other. It can but not usually. It will definitely affect the tread pattern's designed effectiveness at pumping away water and/or snow.

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

I suppose anything is possible but caster usually keeps things tracking correctly. You'd need a major malfunction is those systems to make a vehicle steer or track erratically.

A good example of caster at work is think of a bicycle or motorcycle. It's very hard to balance a cycle at a dead stop, right? You need to put a foot down. Maybe two feet! But start rolling even just barely a little and you can easily stay upright. The bike does it on it's own. The force of the ground pushing against the front wheel coupled with the caster in the front forks pushes the bike upright. It just works on it's own with little to no input from the rider. That's caster, and that's how positive caster keeps you tracking straight in your Jeep, monster truck, Ferrari, Schwinn, anything.

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[Commodus]

Define "moderately". Different sized tires L vs R will absolutely affect steering, feel, alignment, etc. The car will pull to the side with the smaller tire. Different tire sizes is never a good idea. I don't know what the limit is. I guess that would depend on lots of variables.


A directional tire rolling in the wrong direction won't necessarily affect a vehicle "pulling" one side or the other. It can but not usually. It will definitely affect the tread pattern's designed effectiveness at pumping away water and/or snow.


I suppose anything is possible but caster usually keeps things tracking correctly. You'd need a major malfunction is those systems to make a vehicle steer or track erratically.

A good example of caster at work is think of a bicycle or motorcycle. It's very hard to balance a cycle at a dead stop, right? You need to put a foot down. Maybe two feet! But start rolling even just barely a little and you can easily stay upright. The bike does it on it's own. The force of the ground pushing against the front wheel coupled with the caster in the front forks pushes the bike upright. It just works on it's own with little to no input from the rider. That's caster, and that's how positive caster keeps you tracking straight in your Jeep, monster truck, Ferrari, Schwinn, anything.

One needs to know that different manufacturers have different heights for the same size tire and it is not a good idea to run different manufacturers on a 4WD. You can run a tire that is up to 30percent different in height for short periods as a spare but can't use your lockers and best used on the front axle in 2 wheel drive

 

[Greg_L]

One needs to know that different manufacturers have different heights for the same size tire and it is not a good idea to run different manufacturers on a 4WD. You can run a tire that is up to 30percent different in height for short periods as a spare but can't use your lockers and best used on the front axle in 2 wheel drive

Yup, exactly. Differentials generally do not like wheels spinning at different speeds unless it's an open diff.

Tire manufacturers generally are not that far off with their sizing. But as we know with big offroad LT tires there can be more variance than one might expect. Best to keep everything similar and sized correctly.

 

[Minty JL]

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.

I concur, based on the Toe measurements, you should be good. I know with my JL and JT it's the crown in the roads that cause it to "pull" persae.

I've spent plenty of time working with Hunter Alignment racks and everything looks normal for a Jeep

 

[Deleted member 51947]

I had a similar issue, after installing a lift on my JTR, it pulled to the right (would change lanes in under 10 seconds). I have had it aligned 8 times. I did some more research and found that after a lift install, you need to go to the dealer to have the 'Pull Compensation' recalibrated in the Electronic Power Steering Control Module ( EPS Clear Pull Compensation ). I attempted to do this with AlfaOBD, and got hung up at the the Longitudinal and Lateral sensor calibration (ABS Module). Because it failed to complete that calibration it went into Plant Mode, and I had to go to the dealer to have them complete the calibration. Long story, short, It no longer pulls.

 

[ShadowsPapa]

I have had it aligned 8 times.

There's nothing to align. A lift changes nothing. So the second time on the rack was a total waste of time since they can't change anything other than toe or steering wheel centering.

My bet - some ELSE changed.
You misunderstand how a lift works or what it doesn't effect if you think going through an "alignment" 8 times could change anything. All they can do is look at it - you can't change alignment on these other than toe - or if you have adjustable control arms installed, caster, but even that's limited in what can be done.

I question your "source" on that bit about needing to make any changes after a lift - thousands of lifts get done with nothing else changed, especially not going to a dealer to have something done.

Did you also change wheels and/or tires? What else changed at the time of the lift?
Did you move the tires around to try to change the pull? Left to right and right to left, or front to rear, and so on?
Alignments were a total waste of time.

 

[Deleted member 51947]

There's nothing to align. A lift changes nothing. So the second time on the rack was a total waste of time since they can't change anything other than toe or steering wheel centering.

My bet - some ELSE changed.
You misunderstand how a lift works or what it doesn't effect if you think going through an "alignment" 8 times could change anything. All they can do is look at it - you can't change alignment on these other than toe - or if you have adjustable control arms installed, caster, but even that's limited in what can be done.

I question your "source" on that bit about needing to make any changes after a lift - thousands of lifts get done with nothing else changed, especially not going to a dealer to have something done.

Did you also change wheels and/or tires? What else changed at the time of the lift?
Did you move the tires around to try to change the pull? Left to right and right to left, or front to rear, and so on?
Alignments were a total waste of time.

To clarify, it pulled when I picked it up after having the lift installed. The caster was less than 5 degrees, so the shop that did the lift suggested to do inserts to correct caster and camber...it still pulled. The rear axle wasn't square, so I corrected that. Still pulled. Took it to another shop, they found that all measurements (caster, camber, toe, SAI, etc.) were within spec and that it was pulling because of the tires. I cross switched all the tires, and it still pulled. I put the factory tires and wheels back on, and it still pulled. Took it back for another alignment check at a different shop, and they also confirmed the measurements and couldn't explain the pull. Eventually I found out about the pull compensation and it corrected the pull.

 

[ShadowsPapa]

To clarify, it pulled when I picked it up after having the lift installed. The caster was less than 5 degrees, so the shop that did the lift suggested to do inserts to correct caster and camber...it still pulled. The rear axle wasn't square, so I corrected that. Still pulled. Took it to another shop, they found that all measurements (caster, camber, toe, SAI, etc.) were within spec and that it was pulling because of the tires. I cross switched all the tires, and it still pulled. I put the factory tires and wheels back on, and it still pulled. Took it back for another alignment check at a different shop, and they also confirmed the measurements and couldn't explain the pull. Eventually I found out about the pull compensation and it corrected the pull.

But the lift itself didn't do that, something the shop did wrong or some other factor.
A lift won't change any need for "compensation" unless it's done incorrectly.

So where/how did you hear about that compensation (which should not ever be needed with any lift)

Inserts to correct caster and camber? A lift can't change camber - it's impossible, so if it needed correcting it was off from the factory.

Something still is fishy here.............

 

[Deleted member 51947]

But the lift itself didn't do that, something the shop did wrong or some other factor.
A lift won't change any need for "compensation" unless it's done incorrectly.

So where/how did you hear about that compensation (which should not ever be needed with any lift)

Inserts to correct caster and camber? A lift can't change camber - it's impossible, so if it needed correcting it was off from the factory.

Something still is fishy here.............

I understand that the lift didn't make it pull, sorry if the post title is misleading. The only thing fishy is the shop that did the install. I had even called and talked to Clayton Off-Road about this issue. I sent them a picture of the alignment sheet, and they couldn't see anything to make it pull either.

In the end, it was a poor installation that caused the issue. But, again, I figured if someone else had a similar issue, I would pass it on. I found out about the pull compensation from AI. After an exhaustive internet search, I put the symptoms into Chat GPT and asked for analysis. It asked if the pull compensation had been recalibrated. I then checked it on Alfa OBD...

 

[ShadowsPapa]

Relying on AI, not really good. It doesn't take all factors into consideration. lt grabs stuff from forum posts, and can't consider all of the other things that are in play.
The steering wheel centering should have shown up on an alignment printout. If toe isn't the same on each side with the steering wheel straight, there's the problem, however, those doing the alignment likely weren't doing even that bit correctly, either.

Chatbots, Chat GPT - horrible sources of information at times - you have to consider where it's taking the info from. Click the reference link and double-check AI's sources.

 

[Sw00per]

Relying on AI, not really good. It doesn't take all factors into consideration. lt grabs stuff from forum posts, and can't consider all of the other things that are in play.
The steering wheel centering should have shown up on an alignment printout. If toe isn't the same on each side with the steering wheel straight, there's the problem, however, those doing the alignment likely weren't doing even that bit correctly, either.

Chatbots, Chat GPT - horrible sources of information at times - you have to consider where it's taking the info from. Click the reference link and double-check AI's sources.

AI can also hallucinate i.e. make stuff up.

 

[ShadowsPapa]

AI can also hallucinate i.e. make stuff up.

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