I used them years ago, the 80's, when I couldn't go for a ride in the woods behind my house without getting flats from the large thorns there. They are heavy, and can cause flats if they aren't installed properly, and even if they are, after some time, though I never had that issue. I used them on that bike until 2006 when I started to commute with the bike. The bike felt much better without them. If you are on the road, don't bother with them. Get a good tire.