"The Hurdy Gurdy Man" wrote in message
...
In rec.crafts.metalworking Josh Fowler
wrote:

4130 is no lighter than mild steel, their density's differ by only
.02 g/cc.

Oh I'm fully aware of that... my understanding is that due to the
increased strength of the material, you can get away with using a thinner
wall for the part and thereby decrease weight, hence chromoly's use in
weight critical situations. But I do realize that for a dimensionally
similar component there is no weight savings by using chromoly.
Otherwise,
things like bicycle frames wouldn't be made out of tubing with such thin
walls... they'd have regular old thick walls, and have some sort of
magical
weight loss associated with them. That, however, is what aluminum is for!

Actually, a lot of custom bicycles are made with thin-wall 4130 today. If
you really want to see thin-wall tubing on a bicycle, saw through the frame
of an old, high-quality bike made with double-butted Reynolds 531 or
Columbus tubing. They're very darned thin.

Aluminum is a mixed bag. I had an aluminum Allegro track bike when I raced
bicycles in high school. It was 'way too flexible. Some types of bikes
benefit from the flex, but not ones that are raced on roads or flat tracks
by well-tuned athletes.

That was 40 years ago, BTW. I'm far from being well-tuned today. g

Ed Huntress