It depends how the bike folds.
If when the bike is folded the discs are on the outer side or not.
If you look at Helix, the rear disc is between the wheels and protected, the front not.
On the Birdy, both discs are on the two outer sides.
Note that besides the discs, the other fragile element is the rear derailleur.
On the Birdy, its protected (when Birdy was designed, there were no disc brakes, protecting them wasn't an issue but protecting the rear derailleur was).
On the Helix not.
Its always better (if possible) to store a folding bike vertical.
Last edited by Jipe; 07-02-21 at 12:08 AM.