Originally Posted by Jipe

Yes, all Brompton are not great on cobblestones.

But I am afraid that with its very rigid frame, fork and rear triangle + no suspension + almost same width of tires than the Brompton, the Helix will also be poor on cobblestones. The titanium frame + bigger wheels do not mean it will be comfortable on cobblestones, I own a titanium frame road bike with even bigger ETRTO622 wheels on which I can put 32x622 tires and its also not great on cobblestones.

For cobblestones and unpaved paths, the best folding bike is the Birdy with 50x355 tires and full suspension.