Interesting, but one abbreviation seems to elude my comprehension. CF? what is that?

thanks.
In my experience, All my bikes are steel and I've never had any problem with frame breaking, or any parts of it.
Even my current bike is 17 years old, steel, front shocks, and I took it up in the rocky Mountains and rode the heck out of it. damaged my tire, but overall, still running smoothly. had to replace the crank set, but that was due to wear and tear, not because of that trail I rode on, considering the crank set was the original one I had since I bought it in 1999. So I guess if we took really good care of the bike, ie: tune up annually, proper lube and adjustment semi annually. the bike will pretty much last a long time.

W