We recently rented a Ford Fusion with Michelin Energy Saver A/S tires. These tires would follow the rain grooves cut into concrete highways, and the car ould “snake” back and forth. Tire pressure was as recommended. Are these tires softer or do they have thinner sidewalls? What’s the cause of the poor performance?
Probably the tread pattern.
With tire design, everything is a trade-off.
In order to achieve lower rolling resistance for good gas mileage, they had to give up some of the tire’s traction. If you combine that reality with a unique tread design and/or unique road conditions, it is possible to wind up with the situation that you observed.
We bought a new 09 last year with easy rolling tires. When the car had very few miles I could lock the tires in the rain on blacktop a little too easily. With more miles, the tires seem to have gotten better regarding wet traction on blacktop. Give the tires some time to wear in if they were very new when you rented the car. If this is not the case, then there is, as was said, a compromise.
Occasional or rare rain grooves may be an unusual situation and not a deal breaker. Possibly your highway people should stop cutting parallel grooves.
Tread pattern.
It has to do with tread pattern the engineers picked. It has nothing to do with the fact that they are branded as “more MPG” tires.
When too many of the grooves in the tire line up with the grooves in the pavement, then the tires tend to follow the grooves. This is called “Groove Wander” or “Tramling” (I don’t like the last term!).
Obvious it would be nice if the tire designer spaced his grooves so that wouldn’t happen, but the folks that groove pavement don’t have a standardized spacing, so sometimes this is going to happen.
It has nothing whatsoever to do with rolling resistance or fuel economy. However, overinflation tends to aggravate this condition.