Anyone knows if there is available in the market any gear kit for the Dahon Pop? I love this bike but it is has no gears. Wish it had al least 2 gears.

You need to tell us more about the bike, like spacing for the rear hub. If it is the same as for the brompton the same hubs can be used. Is the bike steel or alu? Link plse.

The Dahon Pop Uno.

You or a good bike shop should be able to build a new rear wheel for the Pop around a Sturmey-Archer S2 two speed 'back pedal shift' hub.

If you go with a Sturmey AW 3-speed hub, you'll have to rig a mating hand shifter.

In that case a narrow 5 speed hub is also possible, and a wheel for a Dahon Curve.

Anyone know the OLD (over locknut dimension on this bike? Dahon like doesn't seem to have it
https://dahon.com/bikes/pop-uno-2/

This will determine which rear hubs you can get.