Question - do the semi-hooked rims keep older tubeless tires on the rim after a blowout at 40+ mph when you hit that rock you didn't see? I raced back in the days when we used glue made from the guts of dinosaurs to stick our tires onto the rim. (Well not really how they made it but that glue really was that sticky.) Had as I recall a couple of blowouts on fast descents. Rolled to a stop even using that brake lightly. No big deal. Changed the tire and rode on. That usually happened with old tires but the glue simply didn't care how beat to s*** the tire was. Those blowouts were enough of a non-issue that how many, where they happened and whether front or rear simply didn't get recorded on my hard drive. Now my blowout on a tired clincher at 25 mph 10 years ago? That crash I will never forget. I've gone back to the old glued on tires for all my good bikes simply for that peace of mind. And downhills got fun again!