Originally Posted by
icemilkcoffee
If the pro cyclists union is '100 percent against hookless rims' then I am inclined to believe they have valid reasons.
Also, the foam insert is there for a reason.
I suspect the insert is used in case a tyre burps or fails to seal a puncture, so you're not riding on the rim if you lose pressure. I don't think a regular insert is going to aid tyre retention. The defunct Schwalbe Procore system might help to retain a tyre on hookless beads - maybe they'll come back with a lighter version some time.