just go to some store like rock junction down here in canda were they sell spiked bracelets and dog collars ect.... then buy like there whole inventory of option studs go home take your mountain bike tire assuming it is very knobby.... then using plyers or somehting twist them into the tire were the knobs or whatever are!

its that simply

but it take s a lllllllllllllllllllllllllllllllllllooooooooooooooooooooonnnnnnnnnnnnnnngggggggggggggggggg time!

i liek to do it when watching a movie hehe