531 stays vs. RC2
 

Last year I set out to replace the damaged rear end on my 531 frame with RC2 tubes and report any differences. I have already posted about the difference in adding 1cm of length to the chain stays, and now I am letting you know about changes in stiffness. Well, at least perceived changes in the stiffness of the rear end.

There isn't any.

I'm not seeing the ratings on Reynolds 531, but
https://www.strongframes.com/bicycle...ormation-1999/

The True Temper RC2 appears to be pretty much an average 4130 based tubing. I wouldn't expect huge differences between it and 531.

What about some of the new(er) super-alloys?

True Temper OX/RCX2/OXRC, Reynolds 853, Reynolds 953, Columbus Life, etc.

Of course, there is a trade-off. With stronger steels, builders are using thinner tubing. :foo:

It may also depend a bit on how you're measuring the flex. Have you noticed problems in the past? I have issues with heavy loads on my rear rack on my old Colnago. I can't say it is just the tubes. It could be the rack mounts, or something else.

My Tricross and Jamis Coda just don't feel the same wag the tail effect. I'm still planning some 853 experiments.

And there shouldn't be much at all. People forget that a rear end of a frame is a triangulated structure when a wheel is mounted. So bending stiffness of a single tube isn't really what's going on (but x4 w/ 4 stays).

Even with the super steels the stiffness of a tube with the same dimensional specs, as a normalized 4130 one, is not different. The strength , or point of failure, is. But since we don't stress our frames to the point of failure due to our strength only, w/o a crash, the tubing strength isn't the big factor that it is touted as. But it, strength, is a number that does change thus it's referenced as being important. Andy

it could be the rack swaying.

It's really difficult to influence stiffness with chain stays. They are all roughly the same shape. Thickness isn't as big of an influence as shape. And stronger steel doesn't change how stiff they are absent thickness or shape changes, just makes them less likely to break. So a thinner chain stay made out of stronger steel is going to flex more.