No worries. I apologize for mistaking your tone. As Paul M found from the Grant quote, the reasons seem to be a mix of aesthetics and function. My guess is looks came first and possible practical advantages were deduced later.
In other words, to fit a second tube at all, a frame has to be larger, whatever the reason for adding it. I think that may have more to do with the choice than a theoretical increase in stiffness or being able to use it as a carrying handle, etc. On Thursday, August 6, 2020 at 1:13:40 AM UTC-7 brendonoid wrote: > Sorry that you read that as snarky as It was intended in the complete > opposite direction. I meant that everyone has opinions especially on this > topic but the only one who actually has the math or the engineering report > or whatever they get from the destructive testing of their frames is Grant > Petersen. Just like you I always assumed that it was aesthetic choice and > happen to fit the size frames that have double top tubes so also have > personal experience riding them. > > > *WOBBLY STEEL*: The steel has a deformed surface like a melted candle. > The steel has melted from being overheated because of too many joints and > too much heat in a concentrated location. I always thought but do not know > for sure that it is possible to reverse the annealling benefits of > expensive steels during welding/brazing. I am trying to be clear here in > text and not snarky. > > On Thursday, 6 August 2020 at 01:15:29 UTC+8 S wrote: > >> On Wednesday, August 5, 2020 at 2:27:30 AM UTC-7 brendonoid wrote: >> >>> Riv tests its frames and Grant would have the math on this? I would >>> think? *shrug* >> >> >> No need to be snarky. I know Riv tests their frames and that they pass >> the strictest test for mountain frames. My point was, I don't know if, *in >> the specific case of adding a second top tube*, Grant based his decision >> on an actual test, or engineering numbers -- that is, did he run some kind >> of defection test, see that the larger frames were *flexing >> significantly more than smaller frames* and only then decide to add the >> second top tube to these larger frames? I doubt it, which isn't to say he >> made a bad decision, I just have no evidence he added the second tube to >> solve a *serious, known problem.* That's fine. I think it hurts nothing >> and looks cool. >> > -- 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 view this discussion on the web visit https://groups.google.com/d/msgid/rbw-owners-bunch/2d4f7dc7-dd33-4eed-9a66-464c96911882n%40googlegroups.com.
