This is Grant Petersen's contribution to an RBW thread titled "are Rivendell tubesets proprietary?" from a few weeks ago. Sounds like Silver tubes are newer than your Sam.
"Nothing's proprietary here. Related to that, about 25 years ago the Eddy Merckx brochure listed specs for everything on the frames except head tube angle, which was "proprietary." The same era Gios frames listed frame sizes 48 thru 64, and every head and seat tube angle was 75 degrees.
A while back we showed the new SILVER tube specs on cardboard. Tubing wall thicknesses matter at some level--if they're too thin, that's bad. It's really hard to derive anything useful from them. How much less does a 100mm length of 0.7 weigh than 0.8? Not much, and when you look at the meager gains in weight savings and the significant (I'd say, not everybody would) gains in strength, it's a good argument to go to 1.0, even.
The new SILVER tubeset, which I haven't said much about because bragging about it makes it sound like I don't like normal butted tubes, and that's far, far off---but the SILVER is a single-butted tube. The downtube is 1.1 at the top end, has a long 70mm taper, and has an 0.8mm belly and no but (is 0.8) at the oppo-end.
Somebody who doesn't get tubes would say single-butting is a short-cut. To my way of thinking, it's super smart and better (but not dramatically). You get 1.1 in the stressed area behind the head tube. The belly is 0.8, to resist twisting (talking about it overemphasizes it) and dents (more important if the bike falls over). THe 0.8 at the bb end is on the thin side, but this is a super low-stress area.
The long butt on a long tube allows us to spec butt length according to frame size. This is a theoretical plus but a practical big nothing--- It would be easy to say, "We leave the butt long on big frames, cut it short on smallies," but that doesn't account for light tallies or short stockies. The controversial 2TT is a better way to upstrength the big frames, far more effective than a thicker tube. More heavy too, but another 7oz or so, I don't care.
I looked at the weight savings of long vs short butts, and it was like--a fraction of an OUNCE. At that point, forget it. Leave 'em long.
Sometimes people ask what BRAND of tube we use, and if I'm in a bad mood (twice only in many years), I replied with "Tell me what you know about Columbus SL vs Reynolds 531 vs Tange Prestige." Usually people know labels, not metallurgy. All the tube makers make good tubes, but a good tube is no guarantee of a good joint or frame.
Years ago I'd have spend time on the spreadsheets, but I don't see the point now. It's not laziness or close-to-the vestness, as much as supplying numbers AS THOUGH they matter, AS THOUGH they are in and of themselves tellling, Then people who don't know what they mean feel bad, and who actually does know what they mean?
1.0mm sounds thick compared to 0,8mm, but it's still so thin. I like the 1,1 butts. They make more theoretical sense to me, and in a butt that's so short anyway (even our long ones), there's no time for it to get heavy.
All the steel tube makers, I'm sure, list tube specs. I'm not sure they tell you much. Is eight-tenths of a millimeter too fat for the center portion of a downtube? I don't think so."