I realize the flanges are there to add strength, and that alloy is softer, my question was asking whether or not the extra strength was necessary with modern alloys and rim designs. As far as I have found the flanges are not in fact needed; just look at Motocross, none of those bikes have flanged rims. Not to say alloy is as strong as steel, but flanges aren't the only way to achieve a stiff rim (alloy composition, rim profile/ rim thickness can all be used to create a stronger rim as well), and if I don't need the flanges I would prefer not to have them for aesthetics and ease of cleaning (however small that cleaning advantage may be I'll take it).