A number of years ago we looked into these tires for use on rear of trials bicycle. I actually bought a couple, to find out:
I don’t remember the weight exactly, but the figure 4 or 5 pounds sounds right.
The compound was not grippy, in fact for cycling (or UNI) application they would not be very grabby. They might be fine on moto-trials, but there you have to ad 150 pounds+ for the weight of the bike… making harder compounds necessary.
The size. If it is the same tire I played with a few years ago (and it looks like it), they were too big.
Sorry for the negetives, just thought I would save some one a few bucks before they made the effort to learn what I did.