Hhmmmmm. You can just about get a D-lock from the front wheel-bracket to a frame on a diamond-frame setup, but the bracket itself isn't as solid as those I've seen on other double-deck racks. I don't know if I'd use it if I had the rear seat fitted as it would feel too top-heavy waggly. The sliding section only pivots down when fully extended and conversely only starts to slide forward when the bike is fully lifted. You don't need to lift the full weight but I found I needed one hand to stop the bike falling off sideways and one to lift. The rear wheel-catch didn't have full control of the rear wheel (think mine's 35mm just now) and it wouldn't take much of a shift or slip for it to jump out. The deck starts to slide back when loaded unless it's all the way forward and you'd need a long cable lock to go all the way to your back wheel AND around the bar at the front to stop the mechanism being slid out whilst the bike was still locked. I would recommend that those amongst us able to use these use these when we can if we have a long-enough lock to leave the easier Sheffield stands for those less into heaving things about.