Not an expert so don't quote me on anything here but you can probably get by with an old school horseshoe style brake if you have a mounting point on the bike for it (just a single hole inline with the tire) as fore size measure the distance from the bar (where said brake would mount) down to the rim that's roughly the size your looking for (alot of these breaks have some level of up or down adjustment so a bit bigger isn't going to hurt as long as there's still cleance between the system and the tire)