Thought I would share this with the tire forum... I've got a set of Goodyear F1 GS-D3 17" tires with the Z-rated compound. My brother came into town from Oregon, and I decided to take him for a little spin in the desert; I chose a nice scenic route loop just East of Phoenix, known as the Apache Trail:

http://www.americansouthwest.net/arizona/apache_trail/

About 2/3 of this trip is actually soft sand, small gravel and loose rock, not asphalt; thus, I expected to creep along carefully on my max performance summer tires, spinning my wheels at every touch of the pedal. Much to my surprise, these tires performed amazingly well in the sand and dirt, allowing me to take some truly dangerous curves with ease and prodviding secure enough grip to allow me to do some controlled slides and drifts with no thrashing or fishtailing. Certainly if the ground was wet, it would have been a different story, but I'm gratified to know that I can get around on surfaces other than asphalt (aided by 4WD of course) without flailing about. With about 4800 miles on these tires so far, I just keep falling in love with them -- running 36/34 (front/rear) seems to work best for me; at 38 they really hum on the highway and I don't feel any difference in traction or cornering.

Just thought I'd share that. If any of you find yourselves in the Phoenix area, you have to try this drive; do it on a Monday or Tuesday in the morning, and you'll have the entire place to yourself (I didn't see an RV the entire time).