What are the drag or mechanical resistance numbers for the IGH you use? I've never needed to look but has anyone tabulated such? We have a growing number of sources for methods and result metrics for tires and their aerodynamics to consider.
We built a Sachs-Huret 7-spd IGH (Spectro?) for a demo in my Ozark Mountain shop days (a very high cost sensitivity project) and felt like it was great in the near to direct drive ratios and began bogging when in higher or lower. Slower and more effortful pedaling uphill than a near equal derailleur bike and a greater burden to keep up with on fast level ground. I had chalked it up to a pedestrian CB-0 frame and fork, the cheapest or free front wheel and rim for building the 36°rear and the cheapest 26" tires and tubes. Would we have sensed the same interesting scale of efficiency in the gears had we selected a frame, built wheels and chose tires/tubes as we would have for ourselves? When looking at representative gearing I always saw particular inches relative to being in the particular chainring size as important if for climbing versus for high speed. HP versus torque. Plain old chain drive always seems to win at efficiency and I wonder if wind is the environmental feature variable that can bring you to the edge of sensing both your wheel/tire aero differences but also bring that drive difference to the crux as well. Andy Cheatham Pittsburgh (Were it's always uphill home) On Monday, February 24, 2025 at 2:04:28 AM UTC-5 Patrick Moore wrote: > Even though we are a month or more away from our strong spring winds, > recent storm systems have brought cold, precipitation, and high winds to > Albuquerque. I was out on a ditchbank road on Saturday and got caught in > squalls; on Tuesday on a heavy-headwind return on an out-and-back; and > today had a very pleasant ride, warm in upper 50s with mile high sun, with > 13-15 gusts in 20s, this last time riding the Riv custom, Joe Starck fixed > gear gofast. > > Every time I get back on the gofast, this over the 26 years (in April) > that I’ve owned it, it just feels perfect: fit, ease of pedaling; it’s my > bike geometry and saddle/bar position benchmark. I was struck today at how > easy it seemed to pedal against a headwind of teens gusts to 20s, this > despite the 76” gear that is higher than the flatland cruising gears on my > other 2 bikes; tho’ I took it easy in the hooks. I did not move the chain > to the 19/68. > > OTOH, Tuesdays’ return against admittedly stronger winds on the IGH > Matthews was just plain old work, tho’ again, stronger winds and Ortlieb > Bikepackers in back. OTOH again, I was in 2nd, 65”; it still felt harder to > pedal. And the dirt road Matthews on Sat with 28 1/2” tall knobbies (small, > closely spaced knobs on the Oracle Ridges) — even with fenders — was very > certainly harder to push against the headwind, even geared down to 65” and > 60,” with 175s instead of 170s. Deep in the hooks on all 3 of the bikes. > Riding in the hooks of drop bars gives two headwind advantages, less area > exposed to the wind, but just as much or perhaps even more, new muscles > called into play. > > The gofast, stripped of all except 2 Iris cages, one with a bottle and a > Ruthworks large saddle wedge, and its short* 24 3/4” tall*) 559X27 mm > (actual; labeled 32) RH Elk Passes just seems to cut through the wind > better. > > Saturday’s ride made me sore in the quads and, oddly, in the upper arms; > this compounded by Tuesdays’ ride; but today most of it had gone. You feel > it more at 70 (next month) than when younger. > > I remember 30 years ago when I started riding fixed in our ABQ winds: I’d > fight them and get discouraged. It took me what, 5 years, perhaps more, to > learn to back off and slow my cadence to match the resistance. I was glad > today that I’d internalized that lesson, and the ride was very pleasant and > the pace sustainable despite the harder work. > > I daresay this interests me more than it interests others, but over the > years I’ve found it very interesting that headwinds certainly do affect > tall and fat tires and above all, knobby tires. Pushing y Monocog 29ers or > even the Bontrager Race Lite 26er with heavily knobbed tires was > particularly painful against strong winds.. > > * Recall reading claims on the Rodriguez site that 650C (“see”, 571 bsd) > is better for time trials because the shorter wheels resist the air less. > I’m prepared to believe that. > > Patrick Moore, who will shortly switch from the Phil with 17/19 Dingle to > the SA TC hub with direct and 86.54% underdrive — 76” and 66” for March and > April winds.. > > -- > > Patrick Moore > Alburquerque, Nuevo Mexico, Etats Unis d'Amerique, Orbis Terrarum > > ------------------------------------------------------------------------------------------------------- > > Executive resumes, LinkedIn profiles, bios, letters, and other writing > services > > > ------------------------------------------------------------------------------------------------------- > > *When thou didst not, savage, k**now thine own meaning,* > > *But wouldst gabble like a** thing most brutish,* > > *I endowed thy purposes w**ith words that made them known.* > -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. 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