Just wanted to post, if it is of help to anyone else, that a good place to get bicycles and/or stroller tires repaired is on the corner of Nationalestraat and Sint-Antoniusstraat (not far from fashion designer Dries Van Noten's Antwerp boutique!). I can't tell you what it's called, but the man who runs the shop has helped me twice now, first with the right kind of pump for The Stroller's tires, and today he put a new inner tube on the front left wheel for 15 euro and we are back in business. He is very nice, and between our broken English and Dutch and hand gestures, we understood one another just fine.
If you have time, take Sint-Antoniusstraat east, follow it as it becomes Oudaan, and then turn left/north on the pedestrian street Korte Gasthuisstraat. What a great little pedestrian district! People were waiting in a line out the door from one scrumptious looking bakery, and there were lots of other great boutiques, a tea house, snack shops, and at the center of this sort of starfish of streets, a sweet little plaza with a few of those riding toys for kids, animals on giant springs (what are they called??) which the girls of course had to try.
The tram, it should be noted, is not the greatest solution when we can't use The Stroller. Today and yesterday the girls were late to school though we left earlier than we would if we walked! The trams get caught in traffic and we waited at a transfer between the 7 and 8 lines this morning for a good 15 minutes before the 8 came. Still, it beats walking in the rain or snow.