weight... ha, thats funny truggy... the things weigh next to nothing...
but, yes i would cut them off running anything less that a 40" tire. they are quite brittle and crack if hit just right. when the crack, they create sharp edges that will cut a tire.
when i ran my 39.5" boggers, i kept about 5 psi in them and every once in a while on a hard hit, i would feel it hit. Don't think i ever cracked one, but never had them apart to check either, so who knows.
I am cutting my current ones, and i'm gonna be running 44's. Bette safe than sorry i guess. They will cut fairly easy with a sawzall blade. Just get you some super long Milwaukee "torch blades" and it will roll thru it pretty easy. you will have to use a grinder as well to get them down close.
here is a shot of some shaved runflats for inspiration...
