Coincidentally I am at a place that really eats up tires (EVOC) but that is not point of this post. I am speaking of tires to flip. I went to a truck/tractor tire place and asked for an old tire that weighed a couple hundred pounds and in my truck it went. I'll probably get another ligher one for the gals and a heavier one for the brutes.
EVOC is the Emergency Vehicle Operations Course which is all that high speed pursuit driving stuff. I'm writing this in between runs on the pursuit course. I can't help but snicker when I realize that I am at work now. Braking Box, Decision Maker, Skid Pan, PIT (Pursuit Interdiction Technique)...should be called IFSTDIAPC...Incredibly Fun Stuff To Do In A Police CAr. Anyway, for all you other cops out there, I hope you get to train like this too.
Anyway, tires are really easy to get trainng tools and they are free. You might want to consider storage issues and check with the Missus before you get 8 tractor tires and you live in an 800 square foot 6th floor apartment.