I tried to catch a SEMI tire rolling down a hill without a rim, and I can assure you, a tire, going fast enough, could easily kill you. I know I got the fuck knocked outta me..
.........hell yeah it killed him i couldnt even see the rim and tire coming till it hits him..who ever lost that tire had to be doing a gr8 amount of speed..a air'ed up rim and tire weighs a good 40 or 50 lbs.depending on the weight of the car thats just a examle of a small car tire.