I'm late to this thread, but I have also been through a long process to find a gear setup that works for me. I'm mostly interested in climbing steep hills with my V20, so I've been focusing on the lower end of the gear range.
I like to use the online tool "Bicycle Gear Calculator" at
https://ritzelrechner.de for visualizing and comparing gear setups.
When I got my V20, the recommended stock configuration at that time was a 50x34 crank with 165mm crank arms, and a 11-32 cassette. So I got the same specs. With that, I immediately got severe knee pain after climbing hills.
V20 stock setup from 2018: 50x34 to 11-32, 428% range.
On my previous recumbent I had been riding 152mm cranks for years, so I switched over to those. I also changed the small front chainring to a 30t. So at that point, my configuration was 50x30 to 11-32, total range: 485%, lowest gear ratio 0.938 with 25.3 gear inches.
I was using this for quite a while, but using short cranks means that I have to spin faster instead of harder. When comparing the 152mm cranks to my 155mm cranks, I found that the shorter cranks needed one gear lower for the same climbing effort. Tackling extremely steep hills (15% to 20% grade) still wasn't really possible with this setup, so I switched the small front chainring to 26t. Now I had this setup:
50x26 to 11-32, total range: 559%, lowest gear ratio 0.813 with 21.9 gear inches.
This is what I used for my trip through Norway in the summer of 2022, so it worked quite well for several thousand kilometers. Climbing sustained efforts at 12% grade with a loaded touring bike was hard, but possible:
Back home, I tried out a 24t front chainring to see if it would improve going up my local 20% grade hill. This switched the lowest ratio to 0.750 with 20.2 gear inches. This gear was actually too low, and my front wheel would just slip on this hill. With much practice it might be possible to develop a smooth enough cadence for this to maintain traction, but instead I went back to the 26t chainring that I'm already used to.
Also, with 50x26 to 11-32, the capacity of my SRAM RED 22 derailleur was already being exceeded, meaning that having the chain on the 26t front ring would make the chain too slack on the small cogs of the cassette, and shifting into unsupported gears would increase the risk of the chain coming off.
To address this, I changed the large front chainring to a 46t, sacrificing some range on the upper end, but gaining a full range of usable gears, and better shifting, because with this I could make the chain a bit shorter for better chain tension.
This is what I have currently on my bike:
46x26 to 11-32
Total range 515%,
lowest gear ratio 0.813 with 21.9 gear inches for 9.43 km/h at a cadence of 90 rpm,
highest gear ratio 4.18 with 113 gear inches for 53.9 km/h at a cadence of 100 rpm.
Getting the same range from a 1x setup is possible, but would require something extreme like a 10-52 cassette, and the gears will have much larger steps:
1x setup with same climbing gear and 520% range.
Also, here is my setup compared to the 53x34 to 11-42t setup mentioned by
@Tor Hovland in post #89.
He got very similar climbing gears, and a bit more range at the top:
Bear in mind that crank length needs to be considered for comparing gear setups, as the longer cranks have a larger mechanical advantage, making the effective gearing a bit lower. So for climbing, Tor's setup would actually allow steeper hills. That's one reason I'm considering to switch from my 152mm cranks to 155mm cranks. If they don't give me knee pain, they would improve my climbing gear.
Finally, as discussed in this thread, installing extreme gear ranges beyond the original spec of the drivetrain might require some compromises, and some tinkering such as changing the gear cable ratio somehow, and mixing road and MTB components.
Having the 515% range requires a 41t capacity, which works quite well with my SRAM RED 22 derailleurs without requiring a Jtek Shiftmate, a Wolf Tooth Roadlink, an aftermarket derailleur cage, or anything like that, so I have one less point of failure to worry about, and can use a pure setup with only road components.
My compromise instead is running a 46t chainring instead of something larger, which reduces my upper gear range. But in practice, even now I only use the largest gear when going downhill, so I can live with that. My setup with the unmodified SRAM RED 22 front and rear derailleur and a 11-32 cassette is possibly lighter than other setups with a beefier derailleur and a much larger cassette, and replacing the cassette might be cheaper.
Here is what my current setup looks like with the 46x26 chainrings:
Shifting to the large-large gear (46t - 32t) is possible and usable:
Shifting to the small-small gear (26t - 11t) is not practical but possible, and retains enough chain tension:
So I'm quite happy with the current setup. It shifts very well, has finely spaced gear steps, and it suits my style of riding. I wouldn't mind a bit more range at the top for going downhill faster, but in practice, pedaling above 55 km/h is rarely necessary for me.
