Tldr: These tubesets seem to be roughly equivalent.
I’ve been bike shopping and looking at tube info, just wanted to share info I found in a 1988 catalog comparing Tange #2 tubing, which would probably be considered pretty good and was typically found on nicer bikes, versus infinity and 900, which seems to show up on lower-tier (but still decent) bikes.
Basically, tube thickness seems to be very nearly the same. Tange neglects to list weights of the 900/infinity set, not really sure why, but further down in the catalog lists individual specs of part numbers. Comparing top tubes, all of the same lengths, diameter, and wall thickness (0.9->0.6->0.9).
#2 weighs in at 274g, 900 is also 274g, and infinity is 270g
In theory #2 is potentially stronger, because it is seamless, although probably negligible. Definitely more expensive. 900 is rolled and welded and has a seam running down the center. The catalog doesn’t actually say anything about Infinity having a seam, I think maybe they were trying to position it as more upmarket than 900 and deliberately didn’t mention it? All other sources seem to state it being seamed, though.
I guess, long story short, it doesn’t really matter. I’ve read that Suntour had the best derailleurs on the market until the late eighties, but they were often overlooked because they were cheaper, and of course people equate expensive with better. I imagine there could be a similar case with seamed tubing?
by gregn8r1