Originally Posted by
cyccommute
Not only is it possible, I find it highly useful. My touring bike has a 15.2 low and my mountain bikes have 14.6 lows. I have 20 tooth inner chainring and 36 tooth large cog. A 40 tooth cog would be relatively simple to bring the gear down to 13.2.
My range is 105 to 14.6 on my mountain bikes and can be from 119 to 15.2 on my touring bike, although I have downgraded my high to 110 recently. Still gives me a 720% range. Ive used the low gear a lot and, a times, for hours on end.
A cadence of 90 is 4 mph. A cadence of 60 is around 3 mph, which is brisk walking speed.
And, when the road looks like this (25% grade)
at 12,000 feet, even a 14.6 gear isnt low enough.
Thanks for the reminder that what is or isn't practical really depends on context--I've never ridden in a state like Colorado and sure have never done anything that steep on dirt.
Honest question though, just as a matter of efficiency/conservation of your energy, wouldn't it be better to walk the bike in gravel contexts calling for gearing that low? I'm asking this as someone who tries to stay off of hilly gravel because I'm quite sure I don't know what I'm doing on it.