Originally Posted by
szewczykm
So, I completely understand I could take a poop and lose 100 grams of weight. When I find out that all something gets me is less weight I tune that out. But if a component is stronger and will last me longer or will make my ride smoother somehow, I'm interested.
There are two problems with this idea. First, you're thinking about things in isolation. Suppose you remove 100 grams from a seatpost, 200 by changing to a different crank set, 100 with a saddle, 100 more with a different cassette, 80 on skewers, and 800 on wheels. Now we're talking about three pounds. Nobody "shaves" 40 grams from one part and expects it to mean they'll finally manage to climb some mountain that's turned them away every time until now, it's part of a bigger strategy.
Second, how much your poop weighs has little bearing on your bike. Imagine you're out enjoying a good ride, and there's a hill coming up, so you stop to take a poop. Hopefully there's a bathroom for you to use!
What happens at the second hill? I've heard other people say "I can just leave my water bottles at home to save weight," well, water is kind of nice to have when you're exerting yourself in the sun. If a light weight bike doesn't appeal to you, that's fine and good.
Originally Posted by
szewczykm
If I broke or bent a tiagra crank, and the 105 is $100 more, I might spend the $100 if it's a stronger crank. If it's just as strong but lighter, then I wouldn't.
I can't compare those two, but I've had a few FSA cranks, and I have a pair of Ultegra ones (6700 on one bike, 6500 on another) now. The Ultegra cranks shift much, much better than the FSA ones. Also, chains last me much longer, but I don't think it's the cranks alone. They're also stiffer and I believe they weigh less.