The winter here in WV is killing me. My new 450F needs to be ridden but I need some advice on getting traction in the snow, ice, and frozen ground. I tried some 5/16" hex-head slotted screws which worked pretty well until the ones that I had angled into the rear knobbies pulled out. I angled them slightly so that I would have less chance of them pushing through into my tube. It worked well on the front but the rear screws in the center knobs pulled out in one ride. Has anyone had a a similiar experience? What kind of screws (preferably from Lowe's) work best for this? Also what type of pattern,number of screws yeilds the most traction?