I don't have a sprung saddle right now. The SR saddle on my bike is pretty padded, though, and not that light. I don't really have a sense of what the extra weight of a sprung saddle would translate to in terms of effort/speed? I just started carrying my giant Krypto U-lock on my back rack (thanks bungie net!!) instead of my backpack, which adds a bunch of weight to the back of the bike obviously, and that's going okay so far. I mean, I feel like I'm never going to be the fastest cyclist anyway.