Sensitive to Alignment?

[roblaw]

I have a 2012 3.8. I got my winter tires changed to summer tires (OEM Michelin) and had a 4 wheel alignment at the dealer. After the changeover I noticed that the car seemed to take bumps differently, a bit more harshly but it felt like the tires were losing contact with the road more often on moderate bumps. I dropped the tire pressure a bit because they were over inflated to see if it helped. It did not.

I had always felt the car, despite the ride, was stable and the tires followed the road contour well without that disconnected feeling. This was different and noticeable. Yesterday we had some heavy rain and some gusty wind. I was on the highway and the car was all over the road. I had always been able to drive in comfort at 70mph+ in the rain with this car before and no issues with safety. I had to pull into the right lane and crawl. When I reached my destination I looked to see if there was something amiss. There appeared to be nothing wrong. And then I looked and noticed one rear tire seemed very slightly off camber, the bottom very, very slightly tilted outward.

Is it possible that this camber issue (and I am guessing, I am not an engineer here) could have so affected the stability of the car because the tire is having less contact with the road. The highway instability yesterday was extremely scary, the car just did not feel unstable, it was actually moved several feet on the road from (I guess) a combination of wind and rain, from the center of one lane to another lane.

Is anyone aware of the 1st Gen Genesis being so sensitive to alignment.

 

[Mark_888]

I would take it back to the dealer. I think they did some seriously wrong during the alignment.

 

[mikec]

The tires that were just installed: were they new tires or were they tires on this car last summer? If the latter, I wonder if they got swapped left-right from where they were last summer. Rotating radial tires front wheels to back wheels is good... moving a tire from the left side of the vehicle to the right or vise-verse is generally not recommended. Radial tires take a "set" in the direction they roll; moving a tire to the other side of the vehicle reverses the rotation direction. Not all radial tires have this issue but many (most?) do.

Camber does cause a lateral force to be developed by a tire. Ideally that force is neutralized by the camber from the tire's twin on the other side of the vehicle. And if the camber is excessive, especially when the camber is positive (top of tire is further outboard than bottom of tire - like the old VW bugs), side forces try to torque the tire+wheel+axle such that the axle tries to lift the rear of the vehicle. Old VWs, MGs, Corvairs, and many other cars with "swing axle" suspension (i.e. cars where the axle itself pivoted near the center of the vehicle and acted as the sole horizontal member, aka lateral link, of the suspension) would jack the rear of the vehicle into the air during hard cornering. This changed the camber even more, making the tire run on the outer edge of the tread... leading to a loss of grip/traction. And not very stable feeling for the driver. But it takes a fair bit of camber to have these problems; what the OP described on his car sounds like a small bit of negative camber... and nowhere near enough to create handling issues.

What the OP describes sounds like horrible toe-out angles on either end of the vehicle. Toe-out is unstable and makes the vehicle want to wander. That wouldn't affect how the car felt on bumps however... just steering and wandering. To affect bump harshness, something in the springs or dampers has to be screwed up - stuff not touched by alignments. Or lug nuts on the wheels not tightened at all. A loose wheel - besides being very dangerous - causes rapid wear to the rim (bolt holes) and the wheel studs which the dealer should just replace even if they look okay or serviceable.

One thing about alignments: they really should be done by rolling the car onto the alignment rack. If the vehicle had been jacked up - to replace tires - the geometry of the suspension means the wheels need to move inboard or outboard (generally outboard) when the jacks are lowered. They can't do that much though - once the tires are touching & gripping the pavement so stresses get trapped in the tires & suspension. (that's what causes the skidding squeak sounds you hear as the jacks are lowered - before there is enough weight on the tire to keep it from skidding.) Rolling the vehicle a couple car lengths lets these forces relax and should be done before the vehicle is moved to the alignment machine.

mike c.

 

[Gunkk]

If the tires are directional and were put on backwards, bad things like this could also happen. Not sure if the OEM Michelins are directional tho.

 

[darrell]

The OP's alignment issue begs the question of when should a vehicle have an alignment adjustment?
The tires on my 2010 were replaced around 28,000 miles. The tire dealer suggested I have an alignment be caused alignment was slightly out of spec according to his alignment machine readings.
I refused the alignment because I was not having any issues. Tire wear was even all 4 tires were within 1/64 inch across the tread, vehicle tracked straight and steering wheel was straight. Now at 37,000+ miles wear is still even.
I'm of the opinion if all is well leave alignment alone, don't risk screwing things up.
New tires the dealer will almost always suggest an alignment be preformed for the full tire wear warranty to apply.
Am I missing a valid reason the alignment should be preformed if not having issues?

 

[Gunkk]

If it ain't broke...

 

[GenesisCaptain]

If it ain't broke...

"It doesn't have enough features yet..." said the engineer.