The tightening action occurs under braking. Most cars on the road cannot spin their wheels on dry pavement but the spinning wheel assembly can be stopped in less than two seconds no matter what the speed. The rotating lug nuts want to continue to rotate, thus tightening may take place. This is the reason most trucks use right and left lug nuts. When a wheel assembly leaves a moving truck it can easily become a lethal weapon. Marshall ________________________________________________________________ Sign Up for Juno Platinum Internet Access Today Only $9.95 per month! Visit www.juno.com