I put 20x2.0 Big Apples on my wife's Dahon and they measure more like 1.75, so I don't think you'll have a problem with your rim (especially if 19mm is the internal width). They work great for the type of riding you describe. Mine are the old style Big Apples (HS338), so I can't be sure if Schwalbe changed the sizing with the new version (HS430).