I have an S type Brompton and although I have to adjust the brakes a bit can use a folding basket bag with it, and use it for trips to the grocery store. I was pleasantly surprised by how much it could hold and how that weight actually improved the handling. On another occasion I had to deliver brochures to houses which were fairly far apart and it worked well since I could reach over the bars and grab a brochure after cycling door to door. The downside was heading into the wind as the bag adds a lot of drag, being so large.