I am an engineer, though only a chemical and electrical one, but I believe that is essentially correct. What does happen is that old frames become misaligned over time. A realignment by a competent framebuilder can make a "tired" frame ride like new. And with production bikes, the original alignment may have been poor, so the bike may actually ride better than new.
Of course, theoretically, to become misaligned, the frame had to have been stressed beyond its elastic limit in the areas where the misalignment occured, as a frame which was originally in alignment can only become misaligned if it deforms in places. However, with steel, the fact that the structure had been deformed at a given point does not necessarily make it highly susceptible to failure at that point. If this were not the case, virtually every steel fork would be a "death fork", as the classic way of producing the fork rack is to bend them, i.e. produce plastic deformation, in a mandrel.
It is the ability of steel to be deformed without compromising its subsequent integrity that makes it the best material yet devised for classic bikes. To become "classic" a bike must by definition survive many years, and if it is heavily used this often involves realignments, repairs, and restorations. All these processes work much better with steel than with aluminum, carbon fibre or titanium.
Regards,
Jerry Moos Houston, TX
Kurt Sperry <haxixe@gmail.com> wrote:
> So, do old bike frames lose their sharpness? Maybe this has already
> been beat to death in the archive.
>
> =====
> Chuck Kichline
I'm no engineer, but my understanding is that as long as the frame is never taken to its yield point (permanently deformed) most well made and designed steel frames essentially will last forever, rust permitting. I doubt the modulus of elasticity, which would determine the "feel" of the frame all else being equal would change to any significant degree.
Kurt Sperry
Bellingham WA