Not so much dangerous to people on the road so much as they have the potential to be dangerous to the person working on them, especially if they aren't paying attention to what they are doing. The main hazaed comes during airing up the tires to seat the beads. If the retaining ring isn't properly seated in the gutter, it can come out with extreme force. These type rims should be inflated in a cage (actually, an OSHA requirement) for this very reason. The problem these days is that many trucks that used to run that type rim are no longer using them. They are going to the single peice rims, so manay shops (especially newer ones) simply won't service them and may not even have the proper equpment to service them.
If you have one nearby, check out the local truck stops or tire shops that do actually handle large OTR/construction trucks.
