Originally Posted by
drlogik
The short of it is that carbon frames, any carbon frame is designed to withstand forces within the test parameters. Normal stress from riding, jumping, sprinting, etc are the norm. Stresses from accidents, falls, or anything that can compromise the carbon fiber are not considered norms. Makers of steel and aluminum bikes also follow this.
Yes, carbon is pound-for-pound stronger than steel within those parameters. Get outside of those parameters and the manufacturers will almost always claim that the bike was "used in a manner that it was not intended". This goes for steel and aluminum bike makers to.
However, the question then arises, in daily real-world use, which material holds up to abuse better? You know, the type of use that the makers do not intend the bike to endure. Well, steel bikes are probably the most durable in general but when you get in to the thin-walled steel or aluminum, that goes out the door.
Still, my money leans toward steel being the most durable material, in the long-run (say 10 to 20 or more years of constant use), for a bicycle.
That's my opinion.
I wouldn't argue the point that a steel bike - especially a stout one (vs. super light weight) - will stand up to abuse and / or high volume, long term utility use. But I wouldn't say I could be sure.
The same could be said for my other favorite sport, cross country skiing. There's no doubt that touring skis, wide and heavy will absolutely stand up better than a lighter weight light touring or racing ski to many years of recreational skiing, loaded touring, the sort of thing some people put skis through like messing around on jumps, etc., or commuting through a bunch of variable conditions including ice, debris, sharp transitions where the ski is flexed highly, etc.
But aside from racing, where the weight and engineered response characteristics really do matter, a recreational fitness skier will also enjoy those same characteristics, and durability and the ability to last 20+ years vs 5+ years doesn't matter, and is not even considered.... and frankly, just like CF bikes, hardly anyone I've ever known ever "wears out" lightweight skis or bikes. It doesn't happen except for internet forums were we all hear about the 1:1,000,000 chance occurrences. The huge, huge majority of cases is the user simply wants new stuff, well before the old, high end, super light stuff actually wears out.
The racing ski performs very well and is super durable withiin it's design parameters, but when the teenagers start building jumps and abuse them in every way their creative and immortal teenaged minds can conceive of, or in a simple, unexpected crash by anyone .... well that's a different story, but still breaking and failing is pretty rare.
But you wouldn't get me to do my recreational fitness skiing on anything but high end, lightweight skis because they're less durable and more subject to damage from accidents. That would just be be dumb. It would be dumb for me to choose a frame material for my recreational fitness bicycling for any reasons other than fun (which in turn is based on ride quality, responsiveness, weight and aesthetics). Durability is not a significant issue for me and most other users because it's, well, rarely a factor at all, because it's a damn durable material.
To think that the best characteristics of a bicycle frame material are durability from abuse and long term hard "normal" use is just silly. It's just as valid to value the ride that is more "fun" whether that be because of aesthetics (traditional vs modern, for example), light weight, engineered ride characteristic or designed purpose - or any combination of the above.
This "steel is real" stuff is dumb. Steel is just a material which may or may not make a 'better' bike than anything else. I own aluminum, steel and CF. None is inherently better than another. I could care less if a unexpected hit would damage either more than the other. It's highly unlikely to happen, and that's the way life is.