Just a (somewhat) educated guess, no.............

 

The ride height sensors have nothing to do with actual "height" - they send data on body attitude to the stability and suspension control systems. Height is adjustable by spring changes. IF the car uses the additional Electronic Level Control (rear only) that compensates for weight changes in the rear seat and trunk and does not change suspension height settings.

About the only difference a slightly larger tire outside diameter would make is to offset the speedo readings - a larger OD tire than original rolls less revolutions per mile so the speedo reads slow for actual vehicle speed.

Alignment may be the cause of the lane wandering.

 

Than you Submariner409 ¡
You are right. The height sensors detect relative wheel-to-body so, nothing to do with tire height.
So, I did a bit of research and the MagnaRide suspension really helps getting the car close to the ground. Found this excellent note on it (2003 !) 2003-corvette-technical-article-magnetic-ride-star-wars-meets-the-50th-car
The magnetic ride detects pitch, heave and body roll. In my case Heave is what is causing my problems.
Of course, before al this, I made sure the car is properly aligned, so I discard that source of failure. Furthermore, up to some 40 mph the car behaves perfectly… And the problem surfaced only immediately after the rin/Tire change… so…
As I mentioned, I don’t believe the dealership is capable of such diagnosis, so, I will check the correct connection of

the sensors, alignment and do more tests….

 

In addition to the alignment suggested by Submariner, here are a few other things to consider. Firstly, most roads are crowned in the center to allow for water/rainfall drainage, consequently all vehicles tend to pull to the right or left depending on which side of the crown you are driving. Secondly, you mention variations in asphalt and this could be a contributing factor because when large, loaded semi trucks travel these same roads in many instances after many years those trucks end up making depressions in the asphalt where the tires roll over and when you change lanes and your car tires enter one of those depressions it's like driving in a rut which makes your car wander. In many instances the road depressions are not noticeable but they are there and will affect the attitude of your vehicle.

 

Thank you for your comments HUmmer5. While you are right on your considerations, my problem is that these are the same roads I always drive and the feeling after bouncing (heave) are almost scary.... I do believe something has changed in the electronics.... the feeling os somewhat simmilar to the feedback I get whith the "lane daparture" reaction of the car....

Will do more tests, and keep posting resutls here...

 

Have you tried experimenting with different tire pressures?

 

The mistery was solved. @Submariner409 was absolutelly right.

The dealership did a "by the book" allignment and problem solved. It is curious that the car had an alligment (not in the dealership) and was behaving correcly, didn´t lean to either side, but, evidently something was wrong, and it was corrected at the dealership.

 

This is good to know.I have had sort of this problem from day 1 swapping to 20's. Mostly the bouncing in the right rear. I have had an alignment but not the dealer. I also have a new wheel in the rear and new tires. It still does it. I'm going to bring it to the dealer for an alignment. But with the small snow tires and factory wheels everything rides normal.