>Unlike steel or aluminium, carbon fibre doesn’t work harden so, as long as you don’t crash it, it will be MORE durable than steel. Steel is almost perfectly e

>Unlike steel or aluminium, carbon fibre doesn’t work harden so, as long as you don’t crash it, it will be MORE durable than steel. Steel is almost perfectly elastic below its fatigue limit. It never fails for stress underneath this, since the elastic motion doesn't generate new dislocations or anything. It is true that aluminum has no lower fatigue limit, but outside of crashes, this occurs so slowly as to be meaningless on human timescales. >Also because carbon frames are layed up by hand, you can can have different properties vertically vs laterally. So stiff side to side but with vertical flex at the bottom bracket ...or anything else you want. That is 100% not true. Bike frames are all highly stiff vertically because of the diamond tube shape. There is no practical bikeframe of any material that has non-negligible vertical compliance. That is just marketing fluff.