Metzeler Z-1 and Z-3
Z1 to Z4 tires are getting "old" by now, but you will still find them
for sale. Z1 and Z3 are sold as a pure sports-
tire, while the Z2 and Z4 tires are sold as sport/touring tires. The Z3/Z4 tires is a generation newer than the Z1/Z2 tires, and Metzeler claims that the Z4 tire has approximately the same amount of grip than the Z1 tire, but with 30% more longevity. If you ride many longer trips, and prefer to have plenty of front grip but longevity in the rear, putting on a combination of Z1/Z2 or Z3/Z4 (front/rear) works nicely.
Downsides: The Z2 and Z4 tires are infamous for their lack of grip in the wet. I've had a Z2 spinnin' on the rear while the bike was straight up, just because it was raining. Today, I'd point to the Sportec M-1 and the Rennsport tires - Kai
Metzeler Sportec M-1
The stickiest rubber I have ever tried. All hail M-1! I haven't tried Metzeler's Rennsport, but the M-1's are just awesome. They stick fantastically, and even when they do slide, the let go and grips again in a very confidence inspiring way. I had a nasty experience in August 2002, on the NÃ¼rburgring, where a car put down a spray (fog) of oil in front of me. This gave me some serious sideways action in a tight corner, but the M-1's took this in a completely composed manner: Hmm, I'm going sideways here, and hmmm now I've got traction again. No slapping, no highside, no BS. Just "watch out this could have been dangerous with some other tires". - Kai
I replaced the stock Battleax tires with the M1 front and rear. It was a night and day difference for me. The M1 rolled from left to right and back again with total confidence. The grip the M1’s provided was simply awesome. I found the tire resistant to surface oil and grit and rarely felt it slide even in rough or sandy situations. The tire performed well on grooved roads- a Colorado rider’s nemesis.
I squeezed about 3500 miles out of the M1 before wearing down the center to cords out back. The front is still in excellent health and will probably last for at least one more rear. I intended to get the M1 in 170 to replace my tire, but a sale on the Dunlop 208 steered me toward that tire, which I’ve heard mixed reviews on.
Oh yes indeed. The 208 I just got has some mighty big shoes to fill. - Keith