Never thought we would need this west of the mountains but today I built some homemade studded snowtires for my mountain bike. I found the info through a link on Bike Forums. It's pretty easy. Don't know how long they will last but they probably won't get a lot of use around here.
Home made studded snow tires:
1 pair of old 26" knobbies
Box of 100 ea. #8 x 1/2" lg. pan head sheet metal screws, ~$4.00 for steel. Stainless would last longer.
1 pair of worn out 27" x 1-1/4" tires
sharp spike like an icepick
power screw driver
Poke holes in the tire at the center of the selected row of knobs with the spike. I used every 3rd knob on the third row from the center on each side of the tire.
Install the screws from the inside with the screw driver
Use the knife to cut the beads off of the 27" tires.
Install cut tires inside the knobbies so that the screw heads are covered
Trim the liners to length
Coat the inside of the liner with baby powder to reduce friction on the tube
Mount, inflate, and ride.
Fuzzy seat not included.