Michelin HydroEdge Tires
I just got back from a trip to San Francisco. Drove out on the freeways and then back on the Pacific Coast Highway.
I've got about 2,000 miles on the new HydroEdges, and they are great road tires with a few reservations. The larger size created a speedometer error of only about 1-2 mph at 75, but you can feel a noticeable difference in the gear ratio. The prius feels a little sluggish coming off the line, but you quickly adjust and it is soon unnoticeable.
One big disappointment is the reduction in gas mileage, though I need to run a couple of tanks of gas through the car around town to make sure. I think I am getting about 2-5 mpg less. There wasn't much variation at highway speeds, but you can tell a definite difference in how fast the car decelerates in town when coasting. It seems to slow down at about twice the rate as with the OEM Bridgestones. So much so that it seems like something is dragging.
The tires run quiet at highway speeds, but are a little loud around town -- a minor inconvenience, if they run 85,000 miles on the set. Like all Michelins, they seem well made and are extremely round. No lumps or irregularities like you see with some segmented molded radials, and they run very smooth. They have only one ply in the sidewalls, but have an extra Arimid belt over the steel belts on the tread. I think this is what makes the tread so rigid, giving the tread wear rating of 760.
They grip well on wet and dry pavement, and I am pleased with the performance. I just hope the fuel mileage doesn't suffer too much. By the way, I have heard that the unidirectional "V" tread pattern works well in the wet, but may not grip very good on ice and snow. Anybody have any input on this?