Ole Jackpiner wanted to know what you have to have to race. They won't let you use screw's coming from the inside of the tire most places. If you just put screws into the knobs they will pull out. All racers run their screw's into an inner-liner. It is much easier that you would imagine to very carefully cut a steet bike front tire right along the edge of the tread, it will leave you with a band around 3-4" wide, you will need to make a good cut to butt the 2 end's togathern to fit snugly in your tire. Most everyone starts with new knobbies. You run the screws in with a drill from the outside. There are all sort's of completed products available, including complete tires.
If you arn't going to race just throw screws and your tire and go, it is amazing how good they go. Just get screw's you know won't go all the way through the tire.
Swarty