Had and alignment - skittish?

[Coaster]

I bought new rear tires and had an alignment recently. The numbers look in spec but I know there's a lot to the set up and impact of wear and performance. Mine's a DD right now. After the alignment the car feels, well, kinda skittish. I drive a lot at 80+ mph on a pretty flat concrete toll road (and have since I got the car). It feels like it could dart off one direction or the other but it never has. The back end kind of scoots sometimes, just a little left or right. Is it because something is kinda wacky or is the set up good and I'm just not use to the responsiveness?

[san rensho]

Your alignment numbers look very good. This leads me to believe the problem might be a mismatch between old front and new rear tires. Are the tires exactly the same front to rear? Also new tires can be very squirm for t he first couple of hundred miles.

[Coaster]

Thank you. No, the front and back are not exactly the same, I'm planning on replacing the fronts very soon. I never had a car where I had to worry about the squirmy tires in the first few hundred miles .

[JayG]

I just had new tires put on all around (Hancook Ventus V12 evo2) and alignment done

Mine handles great and sticks like glue

Here are the settings I had them use

Front
Camber -.2 on both
Toe 0.0 on both

Rear
Camber -1.6 on both
Toe +0.05 on both

[Ebell914]

What tires did you put in back? Are they up to spec? If the sidewall is not as stiff as the fronts, it may cause this (speed rating same?).

[thstone]

I am going to guess that the new toe settings might be part of the cause. Your car went from having very high toe in to nearly zero toe.

Zero toe tends to free up the car and can feel skittish or darty and require almost constant corrections to keep the car driving in a straight line. On the positive side, zero toe also reduces understeer and greatly improves corner turn in.

[Coaster]

Originally Posted by Ebell914

What tires did you put in back? Are they up to spec? If the sidewall is not as stiff as the fronts, it may cause this (speed rating same?).

Went with Michelin Pilots A/S 3 in the back. Pilot SS in the front. I believe they are up to spec.

[Coaster]

Originally Posted by thstone

I am going to guess that the new toe settings might be part of the cause. Your car went from having very high toe in to nearly zero toe.

Zero toe tends to free up the car and can feel skittish or darty and require almost constant corrections to keep the car driving in a straight line. On the positive side, zero toe also reduces understeer and greatly improves corner turn in.

Which toe are you referring too, front or back? It does feel like it requires more constant correction, especially since I drive in a (relatively) straight line most of the time.

[opus69]

I did not see any mention of tire pressure. Tire shops frequently inflate to a higher limit for better tire wear. It would not be improbable that they inflated from and rear equally. Over inflated fronts will give a bouncy ride. Mine are 29 psi front and 35 psi rear.

[Coaster]

Originally Posted by opus69

I did not see any mention of tire pressure. Tire shops frequently inflate to a higher limit for better tire wear. It would not be improbable that they inflated from and rear equally. Over inflated fronts will give a bouncy ride. Mine are 29 psi front and 35 psi rear.

Good point I'll fill up today and check them when I do.

[thstone]

Originally Posted by Coaster

Which toe are you referring too, front or back? It does feel like it requires more constant correction, especially since I drive in a (relatively) straight line most of the time.

Both front and rear toe were reduced. Front to zero and rear to nearly zero. That was the biggest change that saw in your alignment numbers and so I am not surprised that you notice it.

[jrj3rd]

Originally Posted by thstone

Both front and rear toe were reduced. Front to zero and rear to nearly zero. That was the biggest change that saw in your alignment numbers and so I am not surprised that you notice it.

This. 12 degrees toe would have required effort to turn that car. Dialing it back makes it respond like a Porsche and not a econo appliance....

[JayG]

Maybe some bump steer?

[healthservices]

When I used to do alignments. Zero toe was a no no unless the car was a track car. If I had to guess... about 70 percent of abnormal tire wear is due to incorrect toe in followed by camber.

You have to realize that toe is set in a rest state. All suspensions have some type of movement even new. as soon as you start moving the toe will try to toe out especially under braking. If your car tends to be more skittish under braking you have too little toe and most likely worn components causing a excessive toe out condition under braking.

[healthservices]

Of course lack of toe will also allow the car to change direction easier at the cost of tire wear.

[LAP1DOUG]

Personally, I would not have accepted that left rear toe number. It should be changed to match the right rear toe.

I just had my alignment re-checked today at zero toe in front, and 0.03 toe in on each side in the rear, and it is dead on steady as a rock on the highway.

Your front camber sucks, but that is another thing entirely.

Good luck.

[Coaster]

Originally Posted by healthservices

If your car tends to be more skittish under braking you have too little toe and most likely worn components causing a excessive toe out condition under braking.

Which components are candidates? I'm considering putting a M030 suspension on and wondering what else to replace while in there.

[Coaster]

Originally Posted by LAP1DOUG

Your front camber sucks, but that is another thing entirely.

Good luck.

I assume that's because it is at the limit? Tell me more, I'm looking into doing some suspension work.

[MaxD]

I'm in agreement with Lap1Doug that you should have never walked out of the shop with that much difference from side to side in rear toe. They should have been spot on both sides.

Aside from that - You have gone from a more straight line friendly street set up to something more track suited. Perfectly acceptable for many on the street but it definitely requires more attention.

If it really bugs you take it back and get a little more toe in on both ends. This time with exact measures on each side.

Unless you have aspirations of driving on a track don't worry about camber. Your tires will last longer. You didn't give us any mileage on your car. It is possible the rear toe links are worn, but I would attribute your new found "twitchiness" to the alignment.

[Coaster]

Originally Posted by MaxD

Unless you have aspirations of driving on a track don't worry about camber. Your tires will last longer. You didn't give us any mileage on your car. It is possible the rear toe links are worn, but I would attribute your new found "twitchiness" to the alignment.

Thanks. No track plans at the moment. 102k on original parts I believe.