Alignment Help: Cross Steering Angle Inclination

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DirtDawg

DirtDawg

"It'd be alot cooler if you did"
10 Year
Joined
Jun 28, 2013
Threads
31
Messages
2,099
Location
The 405
So I have been battling an issue with steering wheel feedback almost the whole life of my ownership. It was even noticeable at stock height. I have almost completely remedied the situation by replacing sway bar bushings, r&r'd the AHC suspension, and this previous weekend replacing the rack & pinion thinking it was the issue. While it did help the issue tremendously, it still remains.

After getting the rack installed, I took it to the local tire shop to get the toe set correctly again. Well after probably 10 alignments on this vehicle I heard something I haven't heard yet: "something is bent in the suspension". Im kind of taken aback, but when I ask him why he thinks that, he takes me to the alignment rack. Heres what he shows me:
full

Sorry for the bad photography, as I cut off what each reading is. Here it is explained:
Camber
Cross Camber
Caster
Cross Caster
Included Angle
Cross SAI
Toe

He explained that the Cross SAI should be zero, and the fact that it was not zero, meant something was bent. "Well why didn't someone show me this before?" He then says that most alignment techs don't even go to the page displaying the cross SAI value, but looked there after feeling the way my cruiser drove. He too felt there was too much "bump steer".

As far as I know my cruiser has never been in a wreck. Ive spent countless hours underneath it and have never seen any damage or any parts that don't appear to align. So I am kind of baffled. If theres one thing I'm not familiar with it's alignment tech so I need some help here.

Can something be adjusted to get cross SAI back to zero? He also mentioned it could be from lifting with the t bars, but why is no one else experiencing this issue?

full
 
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@DirtDawg where did you go for alignment and how old is this clown explaining this to you? SAI or IA is not really adjustable on almost any vehicle, try to max out the the right caster and keep the split between caster reading less than 1* if possible keep the camber close to zero and towards negative. I don't see a real problem in this reading IMO, how did he come up with bump steer on an IFS vehicle unless it is extremely lifted. I know it's been a couple years since I used an alignment machine but it's not something you forget after 25 years. I suggest you show him the explanation of SAI and other alignment terms on YouTube.

Just notice the screen with the specs and you can go as high 3.8* on the caster, I would set the caster 3.5 on the right and 3.0 on the left if your adjustment will allow. Caster is a non wearing angle but could cause steering issues.
 
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Out of recently overcome ignorance, I agree with vipergrhd.

I really never understood caster until I saw this video:

BTW: this guys video series does a great job of explaining complex auto engineering into easy to understand concepts. Highly recommended.
 
vipergrhd said:
@DirtDawg where did you go for alignment and how old is this clown explaining this to you? SAI or IA is not really adjustable on almost any vehicle, try to max out the the right caster and keep the split between caster reading less than 1* if possible keep the camber close to zero and towards negative. I don't see a real problem in this reading IMO, how did he come up with bump steer on an IFS vehicle unless it is extremely lifted. I know it's been a couple years since I used an alignment machine but it's not something you forget after 25 years. I suggest you show him the explanation of SAI and other alignment terms on YouTube.

Just notice the screen with the specs and you can go as high 3.8* on the caster, I would set the caster 3.5 on the right and 3.0 on the left if your adjustment will allow. Caster is a non wearing angle but could cause steering issues.
Click to expand...
Live to Ski said:
Out of recently overcome ignorance, I agree with vipergrhd.
BTW: this guys video series does a great job of explaining complex auto engineering into easy to understand concepts. Highly recommended.
Click to expand...
Thanks guys, I have been watching youtube videos and reading multiple alignment technical sheets and I totally understand all the alignment basics, I guess the part I'm having trouble understanding is what can be adjusted to bring that Cross SAI reading back to zero?

I'm honestly shocked I saw that caster setting yesterday and didn't realize how far off they were. Will getting that caster within 1* bring my cross SAI back in?

Ive been using hibdon because I have a year of free alignments from them and honestly don't have a quality shop around me that I know of. I'm starting to get a little annoyed though. I had three techs standing around my vehicle looking puzzled, then talked to the "master alignment tech" who told me what I stated above. The fella was only in his 30's I presume. But I do agree with him after owning multiple solid axle rigs, what I'm experiencing is close to solid axle bump steer, almost worse because I will feel every tiny bump on the highway and at low speeds. FWIW I am sitting just a hare over 20" in the front and 21" in the back.
 
Ask when was the last time the machine was calibrated, it doesn't take much to knock out calibration specially when the heads are dropped on occasion. Find a shop that has a newer alignment machine to get a different reading. Do u you have aftermarket wheels? Excessive wheel offset could mess with your steering, try swapping a differe6 set of wheels and tires if someone could loan it to you.
 
vipergrhd said:
Ask when was the last time the machine was calibrated, it doesn't take much to knock out calibration specially when the heads are dropped on occasion. Find a shop that has a newer alignment machine to get a different reading. Do u you have aftermarket wheels? Excessive wheel offset could mess with your steering, try swapping a differe6 set of wheels and tires if someone could loan it to you.
Click to expand...
I have asked that before and the answer I got was "Hunter brand machine, we calibrate it every morning". I do have aftermarket wheels, but nothing too crazy. They're method NV's with offset/spacing of 25/6, several others have run this exact wheel.
 
Calibration of the alignment heads are done by Hunter technicians and not by the shop techs. They must run a test to make sure the heads are not bent or out of calibration. I no longer familiar with the newer machines but it doesn't take much to damage or bend the alignment heads if dropped. When I used to do alignments and if I drop the head I request for a calibration check and most often it can be out by a few degrees. Your best bet would be another shop to get a 2nd reading.
 
Sounds good, I wish alignments weren't so expensive.. I might try hibdon one more time and ask them to perform a calibration check before they start. But I'm pretty sure every time I have brought it in they have only touched the toe...
 
Ask if he could raise your caster reading near max and see if that would make any difference. Most guys think just because the the reading is in the green it's ok very few really knows how to do a proper alignment these days. Hope you get this thing fixed soon.
 
So after searching the forum for days I finally found another thread that mentions cross SAI. And they say that the reading is usually inaccurate due to not performing a specific test procedure. I wonder if this is my case.

Alignment results--question:

Its still just hard to believe that my off alignment can be exhibiting this much bad behavior. I can tell that my outer tie rods may still have a little play, but nothing that should be causing this much input. Maybe its just me not being used to an AWD vehicle but my moms Audi doesn't feel anything like this, though different system. If I can't fix this with an alignment I may just consider installing a part time kit.
 
Out of curiosity have you checked your rear axle position <-> Is it pulled further to one side-slightly? Measure the distance from the frame to the inside edge of the rim on both sides and compare.
 
abuck99 said:
Out of curiosity have you checked your rear axle position <-> Is it pulled further to one side-slightly? Measure the distance from the frame to the inside edge of the rim on both sides and compare.
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I'm sure I am partially misaligned in the rear due to being lifted 2", but minuscule if anything. Could this affect my alignment numbers? And if that is the issue, why is no-one else seeing this being lifted?
 
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vipergrhd said:
Just notice the screen with the specs and you can go as high 3.8* on the caster, I would set the caster 3.5 on the right and 3.0 on the left if your adjustment will allow. Caster is a non wearing angle but could cause steering issues.
Click to expand...
I've been running 4.6 and 4.1 degrees of caster as an experiment for the past year. It drives/tracks great at freeway speeds. Any reason, not to run this much caster? I'm running SPC UCA's and so binding is not an issue.
 
My cross SAI is -.4 acceptable range is -.5 to +.5

Re: Axle position: it depends on the age- and how worn the bushings in the panhard, and link arms are. They will soften and compress and allow the axle to pull to one side: (with lift). Even 5mm offset will induce a slight steering correction-was in my case anyway.

Can't say if that affects your cross SAI directly- but it's maybe worth ruling out.
 
abuck99 said:
My cross SAI is -.4 acceptable range is -.5 to +.5

Re: Axle position: it depends on the age- and how worn the bushings in the panhard, and link arms are. They will soften and compress and allow the axle to pull to one side: (with lift). Even 5mm offset will induce a slight steering correction-was in my case anyway.

Can't say if that affects your cross SAI directly- but it's maybe worth ruling out.
Click to expand...
Will check, but at 130k, i don't think the wear is too bad.. May look into the adjustable panhard bar sold through Trail Tailor.
 
Yep I've been having troubles chasing the wheel alignment following a front torsion bar tweak. I raised the front a little as I put heavier spings in the rear to accommodate the rear bar and spare wheel carrier weight, but this lifted the rear end up quite a bit - rides nice though.

Installed the SPC adjustable ball joint UCA, this certainly helped, but I can't get the feel of the steering I had previously, it feels light and a little twitchy, on a full lock turn I find the front end skips a little and a heap more scrub on the tyres, tends to understeer more as well.

My aligment details are:

Caster
Left +3.41
Right +3.11

Camber
Left -.14
Right -.37

Toe
+.5 for both.

I might try and get the right caster a little closer to the left, and other advice would be welcome.
 
Batlowboy said:
Yep I've been having troubles chasing the wheel alignment following a front torsion bar tweak. I raised the front a little as I put heavier spings in the rear to accommodate the rear bar and spare wheel carrier weight, but this lifted the rear end up quite a bit - rides nice though.

Installed the SPC adjustable ball joint UCA, this certainly helped, but I can't get the feel of the steering I had previously, it feels light and a little twitchy, on a full lock turn I find the front end skips a little and a heap more scrub on the tyres, tends to understeer more as well.

My aligment details are:

Caster
Left +3.41
Right +3.11

Camber
Left -.14
Right -.37

Toe
+.5 for both.

I might try and get the right caster a little closer to the left, and other advice would be welcome.
Click to expand...
Im no alignment expert, so somebody definitely correct me, but the +.5 toe on both sides while in spec seems like it would cause some tire chirping issues when turning.
 
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