Lest my meanderings stray beyond polite list header protocol, I’ll post these meanderings under a new header.
I find discussions such as this one fascinating, though all my opinions come only from modestly adequate “seat of pants” experience over the years; no science was used in these speculations.
It’s interesting to see that the lighter frame felt stiffer than much heavier ones. I daresay that the miles-long stays flex more, all equal.
No information here about Rivendell weight limits, but some anecdata about how, at least in my experience, the frames that feel “fastest” or that handle heavy loads better don’t always check the expected tubing boxes.
I’m ~165 (Down from 170 — Orthodox Great Lent!) but often carry quite heavy rear (and sometimes moderately heavy front) shopping loads; just 10-12 miles return; but — and I’ve said this before, but you’ll keep hearing it — the best = stable-est rear load carrying bike I owned was a very light (compared to my custom Riv framesets) early ‘70s Motobecane Grand Record, a 58 c-c IIRC, with a light Tubus Fly for the panniers. I carried up to 50 lb in the back and that thing was very surprisingly stable; more so than my Ram — much stouter; or even my current normal gauge thinnish-wall 531 Matthews IGH errand road bike, also with a (Bilenky-modified) Tubus stainless steel Fly. The Ram and the Matthews wag much more readily than did the Motobecane — I really don’t know why.
Back to Rivendell stiffness. The Ram was very nice (I had a blue one) but it didn’t feel “spritely” as my best Riv custom or certain other and, in fact, stouter-tubed bikes have done — this in acceleration and in handling. The Matthews is a geometrical clone of the 2003 Riv custom road, with OS tubing and conservatively thick walls, that it replaced; over the 17 or so years I rode it the Riv always seemed to be holding me back in subtle ways; getting on the non-OS, thinner-wall tubed Matthews was a revelation.
OTOH again — and y’all have heard this before — an old Herse that 2 others had sold on because it felt too stout for them felt for me very spritely indeed and encouraged 1 tooth smaller/1 gear higher in back, consistently over the ~2 years I owned it, this despite non-wonderful wire bead 32 mm Pasela tires. I sold that one on because I don’t like low-trail handling.
I rode the 2018 Matthews “road bike for dirt” to and from church today, along the ditchbank roads, with the very light and fast-rolling Soma Supple Vitesse SL 48s (~51 actual) and that thing just flew on the hardpack. Thinwall tubing, but OS with a compact frame. Again, a “1 tooth smaller in back” frame with the right tires.
Aside, speaking of excessively oversized and thickwalled tubing and its effect on how a bike rides: I am within 3/16ths of an inch of actually getting around to building up that 2012 Monocog 29er, which I had planned to do on Sat, only I virtuously decided to get ahead on a couple of resume projects instead. So we’ll see if my zeal carries over to tomorrow.
Here’s the point about the Monocog: the tubing is so thick that, really, I adjusted seatstay tire clearance with a hammer. And yep, the thick tubing affects the ride. Now, it’s not horrible, but the ride is just “meh,” only with a beater like this I don’t start with high expectations, so the end result is not terribly disappointing.
[I squoze 72 mm actual/3" mm labeled tires onto a frame built for 55s, but the within-spec tire/rim runout in the rear had the side knobs rubbing the seat- and chainstays. I took a hammer and a mandrel and beat 1/4” indentations into the seatstays so that at least I’d not have to worry about rub there; the chainstays were factory indented. That was a lot of work!]