Pure slicks.
As I thought , the slicks did make me go faster. Smoother road as compared to my previous Panaracer T-serv 1.75. This 1.5 Xenith made me go faster, and when I did chiong , I felt that the rolling resistance became smoother , as though the bike was urging me to chioing more
As you might have guessed , this tire should not be intended on use on wet grounds, though Sheldon Brown says differently.
Bicycle tires for on-road use have no need of any sort of tread features; in fact, the best road tires are perfectly smooth, with no tread at all!
Unfortunately, most people assume that a smooth tire will be slippery, so this type of tire is difficult to sell to unsophisticated cyclists. Most tire makers cater to this by putting a very fine pattern on their tires, mainly for cosmetic and marketing reasons. If you examine a section of asphalt or concrete, you'll see that the texture of the road itself is much "knobbier" than the tread features of a good quality road tire. Since the tire is flexible, even a slick tire deforms as it comes into contact with the pavement, acquiring the shape of the pavement texture, only while incontact with the road.
People ask, "But don't slick tires get slippery on wet roads, or worse yet, wet metal features such as expansion joints, paint stripes, or railroad tracks?" The answer is, yes, they do. So do tires with tread. All tires are slippery in these conditions. Tread features make no improvement in this.
Taken from:http://www.sheldonbrown.com/tires.html#hydroplaningMaxxis wording on the tires are prolly tread indicators. So far , this is the 2nd day I have used it for my commute to school. The tires does collect dirt easily and make the tire seem old. Yet a reasonable inference can be taken from the centre line rubber thread that the tires have not worn out yet.
However sadly , science cannot seem to work on certain people who choose to put their education lying around instead of bringing it with them.
Great tires! 76 bucks a pair and certainly a decent upgrade for anyone with the need for speed.