Handling problems after service - opinions please.

[Rash]

I'll provide all details and let you guys decide what is pertinent.

2006 Mustang GT 22,000 miles - almost all highway, so suspension is in great shape - no worn parts. Stock 18" tires, stock suspension - not lowered.

Took the car in for oil/tire rotation/alignment. No problems at all before the visit - alignment was just preventative maintenance.

Afterwards, it didn't want to track straight - constantly fighting to keep it from drifting left and right. Took it back to recheck the alignment - they said everything was good. So, I checked the tire pressure (Accu-gauge dial type gauge) and it read 24 all around! So I filled to 32. thought that would do it.

It actually seemed worse - felt like driving in heavy wind with no wind. Took it back again - again everything in spec (this time I got the printout), BUT, they said tire pressure was at 45! Long story short, my "Accu"gauge was off by about 12 PSI.

However, I'm still having issues. Car tracks straight and steady now, but I'm getting significant tramlining (tendency for the car to pull in the direction of a longitudinal rut or crease in the road). Never did that before. Tire pressure is definitely correct now. No bumpsteer at all.

Here's the alignment results:

Camber: Right -.06 Left -1.0 Total -.03 Factory Range: -.08 to +.08
Caster: Right +6.5 Left +7.0 Total +.05 Factory Range: -.08 to +.08
Toe: Right +.05 Left +.08 Total +.12 Factory Range: -.10 to +.30

So, questions:

- Is it possible for the alignment to be incorrect even if the print out says all is within spec?
- Could the tire rotation have brought on the tramlining (i.e the tread wear on the front wheels is different than the ones that were there before the rotation)?
- Is tramlining usually due to tires or suspension/alignment?
- If it is in alignment, could they have messed with something else that could cause tramlining?
- What do you suggest I do next?

Thanks in advance.

 

[SoundGuyDave]

With a fully stock suspension, the ONLY adjustable paramater is toe. Camber and Caster are both fixed, and not adjustable without adding parts. It is possible for toe-out to create a "darty" feeling, but since you are toed-in, and well within spec, I would bet it's in your tires. Try "un-rotating" them and see if the issue goes away. Also, take a look at your former front tires. I don't know if they rotated front to back, or crossed them, but try to find out. Run your hand back and forth across the top of the tire, from inside to out and back, and see if you feel any ridges, that might indicate a saw-tooth wear profile. This would indicate a toe issue. Next, look at the inside edge of the tread and compare it to the outside edge, and see if it looks like it's worn more heavily on either edge. That would indicate a camber-wear issue. Finally, take a look and see if you can see certain spots on the tires that are more worn than others (cupping), as this would indicate a balance issue (tramping) or failed dampers. Sometimes you can have issues with a rear tire that you don't notice until you get it up front... The rear axle has a lot more mass to damp out a minor imbalance that would become quite evident on the lower-mass front. If you "unrotate" the tires, and the problem dissapears, then I would start shopping for tires. Also a good excuse to pick up some nicer wheels, while you're at it!

 

[Rash]

With a fully stock suspension, the ONLY adjustable paramater is toe. Camber and Caster are both fixed, and not adjustable without adding parts. It is possible for toe-out to create a "darty" feeling, but since you are toed-in, and well within spec, I would bet it's in your tires. Try "un-rotating" them and see if the issue goes away. Also, take a look at your former front tires. I don't know if they rotated front to back, or crossed them, but try to find out. Run your hand back and forth across the top of the tire, from inside to out and back, and see if you feel any ridges, that might indicate a saw-tooth wear profile. This would indicate a toe issue. Next, look at the inside edge of the tread and compare it to the outside edge, and see if it looks like it's worn more heavily on either edge. That would indicate a camber-wear issue. Finally, take a look and see if you can see certain spots on the tires that are more worn than others (cupping), as this would indicate a balance issue (tramping) or failed dampers. Sometimes you can have issues with a rear tire that you don't notice until you get it up front... The rear axle has a lot more mass to damp out a minor imbalance that would become quite evident on the lower-mass front. If you "unrotate" the tires, and the problem dissapears, then I would start shopping for tires. Also a good excuse to pick up some nicer wheels, while you're at it!

Great reply - thank you for taking the time to respond. I was planning on un-rotating - I'll try that this weekend. I don't know which way they rotated - they use their Quick Lane thingy for that, and I'm sure I won't get a reliable response from anyone over there. I'll try though. I know they usually just do front to back, so I thought if maybe they did the cross thing this time it could affect handling.

Question - would the printout indicating that it's in spec be enough for you to conclude that it's definitely not the alignment, or do you think it's worth checking the alignment again elsewhere?

 

[SoundGuyDave]

Question - would the printout indicating that it's in spec be enough for you to conclude that it's definitely not the alignment, or do you think it's worth checking the alignment again elsewhere?

The print is computer generated, so GIGO applies. If the tech screwed the pooch setting up the sensor heads, it could be off, but you had it rechecked, and screwing up EXACTLY the same way twice is vanishingly improbable. If your steering wheel is straight, then you're most likely okay. If you un-rotate, and the problem still exists, then by all means take it to another shop, but I'm betting the tire swap will reveal the culprit...

 

[Rash]

Thanks again for your help.

 

[Hawgman]

From what you have said my money would be on the tire rotation being the culpret. But I will say... in my opinion something sounds a little odd. Don't think I have ever heard of someone having 22k miles on their car and getting an alignment just for preventative maintenance. Most people are either a little more frugle, or subscribe to the if it isn't broke don't fuck with it theory.


Just one more reason that I run different size tires on the rear than the front. Tire rotations? We don't need no stinkin' tire rotations.

 

[Buzzystang]

If the tech was worth his salt, he would also have provided you a printout of the alignment readings before he started, so you can see what changes were made.

If you still have problems after rotating the tires back, then see if you can get your original alignment readings and have the tech set it back to what they were. Some alignment machines can save the customer settings in the computer, but most of the time the techs don't bother to do that - they just issue the printout. They may have put a printout in with the original service record. It's a longshot, but probably your only hope.

 

[Rash]

Don't think I have ever heard of someone having 22k miles on their car and getting an alignment just for preventative maintenance. Most people are either a little more frugle, or subscribe to the if it isn't broke don't fuck with it theory.

Well, I usually get a good 40,000 miles or more out of my tires (mostly highway), so I figured for $55 might as well make sure I aint causing any uneven tire wear with an alignment that's off. I think from now on i'll stick with the IIIBDFWI theory you mentioned.