do I notice? yes. I have 5 bikes and they range from 15.25 pounds to 21 pounds. I also notice the weight of waterbottles, but on a hot day, the water is needed. I also notice the weigh of a heavy seat and seatpost, but I gotta have a comfortable seat. but I don't use a saddlebag.

for 20 minutes of climbing, the extra weight is not a big deal. in fact thats my short training ride, I want my heavy bike. but on long rides with the guys, I gotta have the 15.25 pound bike.