Frustration. I've been riding with some kind of persistence and regularity for six months or so. Bought a modern lightweight road bike with fancy components and a bunch of spandex. I ride at least 100 miles every week, usually 20 miles or so at a time but sometimes more. I find my natural pace to be around 18 mph in this level country and I maintain that pace most of the time... so I should be getting strong, no? No. I go out with a bunch of riders for a 30 miler and I'm left in the dirt by 75 year olds and 260 pounders. What's up with this? I'm 53, thought I was fit, not carrying extra weight... Am I just a weak weenie?