I came back to bike touring after years of extensive ultralight backpacking. I dropped more than half the weight I used to carry on the bike (that was over 40 pounds), but it was still nearly double what I carried on my UL hiking trips (eight pounds for three-season trips). I had to pack for two--me and the bike. The bike needs tools and spares, and the packs themselves are necessarily more durable and heavy. So if you're getting in to biking from hiking, and are being weight conscious, be aware of those issues.