Ledburner's recent posts about half-step Rohloff gearing and some PMs/queries caused me to dig out my old gear charts. Though likely too esoteric for all but the hardcore gearheads, they might still be helpful to others thinking about their gearing needs so...Thoughts Ahead:
On my derailleur bikes, I generally prefer half-step-and-granny gearing because it is easy to find and shift sequential gear combinations and to fine-tune cruising gearing for riding against winds or in gently rolling countryside while accommodating hill-climbing needs. Low gearing is still readily available via pairings of the smallest (3rd) chainring paired with the 3 or 4 largest freewheel/cassette cogs. I've arranged my most-used crusiing gears to run with minimal chainline deflection and enjoy quiet pedaling and long component life as a result.
Half-step gearing works best with 7 or fewer cogs to a) minimize chainline deflection and b) ensure the half-steps are still noticeable; if they get too small, they don't make "enough" difference to be worthwhile;I found ~7% to be the minimum practical difference between front shifts for my needs. It is for that reason I largely abandoned my own plans for a half-step Rohloff onmy Nomad (and because the chain tensioner -- depending on type -- counters some of the long-life benefits of the Rohloff I so value). It might yet be practical on one of my rando bikes because a chain tensioner would be required anyway and that bike is unlikely to be used for expedition touring.
My first goal in setting up my Nomad's Rohloff gearing was to ensure I had gears low enough to carry expedition loads up really steep terrain. The second goal was to ensure the cruising gears I value most in my randonneur bikes were also available (or very closely so) in the Rohloff drivetrain. To ensure comparable comparisons despite differences in wheel/tire size, I standardized on gear-inches as my unit of measure across all drivetrains and wheel/tire sizes.
There's several reasons why my gearing is so low on all my bikes and why I prefer half-step gearing on my randonneur bikes. It starts with bad knees, the result of a car crash when I was in high school. I started cycling "with intent" as physiotherapy and this required I use care to avoid setbacks while everything healed. My knees are still kind of fragile and I find I cannot pull gears over the mid-70 gear-inches and then only briefly; any gears above that are mostly just place-holders so the rest of the progression is where I want it. This means I must pedal with a higher cadence in lower gears to ease the strain. The cadence I generally fall into is 110-120rpm and never below about 80-85 going uphill. I make up for low gearing by pedaling faster and with less pressure.
I live in a town surrounded by steep hills on three sides, opening to flat farmlands to the north. This means on my longer 300-400km day rides, I need to not only accommodate climbing on hills but also smaller changes on flat or rolling terrain or due to unbroken winds. Half-step derailleur gearing does this most ably for me. For comparison, I've included a chart showing the crossover gearing used on my past Sherpa. The yellow combinations are the ones with minimal chainline deflection and so were most used by me to minimize wear and noise. A 9-sp half-step with the same cassette makes a very nice progression but is largely impractical because of difficulty finding a suitable front derailleur for the <5t gap and because of the larger width and greater chainline deflection of a 9-sp cassette compared to a 5-, 6-, or 7-sp cogset.
After I got my Rohloff gearing dialed-in my biggest physical adaptation was the even gaps between gears. Most derailleur setups are logarithmic in their progression: Bigger gaps between the lower gears "feels" like smaller gaps between the higher gears. I soon learned when I wanted "big" differences between lower gears on my Rohloff, I could get there by shifting two or three gears at a time. Works great, especially where I have the shifter placed handy on my Nomad. See:
https://www.youtube.com/watch?v=lVh3qb4F0sQ In the first attachment below, I offset my gear charts to show how and where the individual combinations compare across my four most-used bikes. All my preferred crusing gears are marked with a ©. The half-step gearing is all on the middle and large chainrings except for the lowest 3 or 4 gears marked "L", which use the innermost (3rd) chainring [I have offset my BB spindles so the inner chainring is aligned with these lower cogs and the middle and high rings are considered like a double for chainline]. The leftmost chart shows what I thought would be the best "half-step" Rohloff setup for my needs. In the end, I didn't find it offered enough advantages to be worth it on my Nomad.
The individual derailleur charts in the second attachment show the progression of double shifts to get sequential half-step gears. In practice, I shift at the rear (full steps) to accommodate large needs and at the front (half steps, equivalent of half a rear shift) to accommodate small needs/fine-tune my gearing. Cruising along, I use the combinations marked with a © almost exclusively.
A last note: As my Rohloff chart shows, I use it as a two-stage gearset. I use the upper range (Gears 8-14) for most needs and the lower range (Gears 1-7) are what I use for hill work. Most riding is done in my Gear 11 direct-drive or in the gear just above or below it (Gear 10 or Gear 12).
And yes, each of my bikes has a gear chart taped to the handlebars.
They add pleasure to my rides along with my constant mental time-speed-distance calculations.
Best,
Dan.
