Not possible for the medium + large cases.
All the hard sided cabin bags I've looked at recently have been no more than 2.5kg at most. Even the large form factor of those cabin bags have been under 5kg. Are you sure there wasn't some contraband stashed away in a hidden section of your bag?
Have got the 4 wheel roller. Problem is it takes away just under 5kg from weight allowance at the outset. By using cloth bags + 2 wheels can easily save 2kg or even get full luggage allowance by using cloth bags without wheels.
The smaller bag has really bad reviews because of terrible quality.
Looks like a good price for the pair. Anyone have these?