Originally Posted by
aprieto28
So if i understand rude bob. there may not bee much difference between this 4130 tubing and the 725 tubing?
The numbers are in the comparison between Reynolds 525 and 725 in my first reply. 525 is not heat treated 4130 chromoly while 725 is heat treated chromoly. 725 is stronger, so the tubes may be drawn with thinner walls, making them lighter. The downside of thinner walled tubing is that it's not as stiff as thicker walled tubing of the same diameter and is at greater risk of getting dented in use.
Most builders prefer to use heat treated tubing rather than post heat treat a frame built of annealed tubing because of the high risk of warping the completed frame out of alignment during the heating process and the difficulty of cold setting heat treated tubing back into alignment.
So no, they're not the same. 725 (heat treated) is different from non-heat treated 525 chromoly. It's similar to comparing heat treated 853 to non-heat treated 631 even though they have the same chemistry.