Hey Lum, Appreciate you staying with me on these questions.
The next one being my 3rd Riv, I want to think it through a little more before pulling the trigger. Hence all these questions. The big question in my head is, with its specific deliberate design, how heaver is Roadini as compared to Roadeo. Another part I'm pondering (probably only the designer can answer) is if their previous iteration of road bikes is lighter because of a different thickness/tapering proportions, what's the compromise. There's got to be a reason why they changed the design from Roadeo. Or is it that due to the type of tubing/material, the lighter (yet strong enough) design is only possible in MUSA frames?... On Wednesday, 31 October 2018 13:12:43 UTC-7, Lum Gim Fong wrote: > > Roadini specs from RBW: > Roadini: > “0.9 x 0.7 TT and the length is cut from the butt (0.9) end. So you get > the 0.9 up at the front, where top tubes buckle. The 0.7 is on the thick > side for a belly (though it's the same as old Columbus SP, which was 1.0 x > 0.7 x 1.0--as a historical reference). > > The 0.7 seat-post end is light. But that's the least stressed portion on a > top tube. We use the same tube on our heavier bikes, but they're not > "chopped from the butt." Weight difference is minimal. > > DT is a tapered tube--31.8 x 1.1 at the head tube, to 28.6 x 0.8 at the > bottom bracket. It's another "chopped from the butt" tube, to minimize the > 1.1 length, but still giving it a lot of buckle-resistance. > > You might wonder why a tapered tube here, and why not fatten it at the BB? > (Like Serotta's old "Colorado Concept" tubes were.) Well...almost all of > the tilting/fatigue stress down there at the crank is localized on the base > of the seat tube. I've seen 30 bikes (not all ours, thanks...) break there, > and zero break at the downtube. Strain gauge stess analysis reveals that > the stress is light on the down tube, heavy on the seat tube. > > That's why, on our TIG'd bikes, the seat tube is 1.1 there, and ovalized > laterally to 34.9 x 28.6.” > -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To unsubscribe from this group and stop receiving emails from it, send an email to rbw-owners-bunch+unsubscr...@googlegroups.com. To post to this group, send email to rbw-owners-bunch@googlegroups.com. Visit this group at https://groups.google.com/group/rbw-owners-bunch. For more options, visit https://groups.google.com/d/optout.
