Art Harris <[email protected]
> "Richard Ney" wrote:
> A. Muzi wrote:
> > > Titanium rail failures are common yet steel failures, even among a vastly larger sample with
> > > vast quality differences, are not common.
> > What's the failure mode? A bend, kink, or something catastrophic?
> Shear failure. The reason for my question is that most current saddles are not available with
> solid steel rails. I'm looking for the next strongest type. It gets confusing when you start
> seeing terms like Vanadium and Manganese.
Marketing speak. Vanadium and manganese are alloying elements in steel (ever buy a "chrome vanadium"
screwdriver?). For example, Reynolds 531 is manganese-molybdenum steel (as opposed to Cr-Mo which is
chromium-molybdenum). I have a Selle Italia Sphere with "FeC alloy" rails. Duh, every decent steel
has iron and carbon in it.
> A booklet that came with my Rolls Classic saddle shows the labeling that Selle San Marco uses.
> They use "C" for steel, "M" for Cr-Mo (not manganese), and "T" for titanium. Since Cr-Mo IS steel
> this is very confusing. I THINK they use "M" to mean tubular Cr-Mo, and "C" to mean solid steel.
As with bikes, Cr-Mo probably indicates stronger than generic steel, but then they can make the
tubing walls thinner. I don't know that the "C" ones are solid - solid steel rails would be
> I had a hollow Manganese rail fail once, so I would definitely avoid that. I'm trying to
> determine the relative strength of hollow Cr-Mo vs. solid Ti since those seem to be the most
> available types.
I think you can assume that reasonable steels will be stronger than Ti but what you don't know is
the relative quality of design/manufacture. Anything can fail once. Did it really just shear right
off, no bending first? Could there have been a stress riser from the seatpost clamp?
I hear from this thread that Ti rail failures are common. That's a bit worrisome. Any common
features among the failures (mountain bikes, large riders, poorly designed seatpost clamps, seat all
the way back on the rails)?