Originally Posted by
Squeezebox
So if I have this straight 4130 means anything above high tensile to top end 853 and such ?? Kinda makes it hard to know what you're getting.
No. Look at the Reynolds chart in Scooper's post. Only 725 and 525 have carbon amounts that qualify for 4130. 853, 631 and the 900s are much lower carbon alloys.
We are losing sight of what really matters. Tube diameter and wall thickness. These are all steels. If we make two bikes, one from gas pipe and the other from 953 with the identical diameters and tube thicknesses, the will weight the same and ride identically. (Not quite true. Stainless steels are a little different, both in weight and stiffness, but by maybe 2%. Still those judging the frames will have a tough time telling them apart.) Until they jump them off a high jump, then the gas pipe will bend. But 50 miles of racing on halfway decent roads. No difference at all.
The huge advantage of high strength steels is that they allow framebuilders to use much thinner wall tubings. This allows the diameters to get enlarged for stiffness. If you are willing to have a frame that dents easily, you can have the light weight and stiffness made possible by the high end tubes. If you stick with the old smaller diameters to get the wall thickness up and hold the weight to something reasonable so you can have a durable, bump resistant frame, the strength of the tubing and therefor the "whiz-factor" matter far less.
Ben