A couple of threads about gearing here today had me thinking about Frank Berto, who was Bicycling Magazine's technical editor "back in the day." He wrote clearly and frequently about gearing set-ups, and had a big influence on the way I set up my bikes. His book, "Upgrading Your Bike", is still a very good read if you want to understand your bike, and especially if you own a bike from the 60's through 80's you want to fiddle around with.
Frank is a proponent of low gears and spinning (vs. mashing). Since the topic often comes up here about low gears, I thought I would convey his recommendations on the low gears that one should have for various types of riders. Understanding his recommendations means that you have to understand the concept of Gear Inches (some background and a gear calculator here: http://www.sheldonbrown.com/gears).
Here are Frank Berto's recommendation for the low gear that "wise old riders" should have on their bikes. In most of the cases outlined below, he recommends that "Strong Young Riders" can make do with gearing that is 5 Gear Inches higher, so if you're feeling brave or strong you can go 5 inches higher (though he also used to say that "strong young riders" who wanted to keep their knees their whole lives would be well advised to move to "wise old rider" low gears when they were still young...that's what I did).
One of his frequent complaints was that most bikes intended for recreational use were set up by manufacturers with gearing that was more aimed at racers than "normal" use....IMHO this got a lot better during the mountain bike boom, especially with the growth of triples...but I still see people struggling with too-high gears and, of course, we see variations of these questions asked here on BF all the time.
Without further ado, Frank's "low gear" recommendations:
Kind of Riding / Recommended Low Gear (in gear inches)
Racing (level course) 55
Racing (hilly course) 45
Triathlon (level course) 55
Triathlon (hilly course) 40
Recreational riding (flat terrain) 40
Recreational riding (hilly terrain) 32
Recreational riding (steep hills) 27
Loaded touring (flat terrain) 24
Loaded touring (hilly terrain) 19
(note: for loaded touring in hilly terrain, he also says that even "strong young riders" should have a low gear of 19).
Of course, once you pick a low gear, you have to arrange the rest of your gearing to have a proper "high" gear...and his book has pages and pages of discussions on various ways to get there. Frank's book is almost always available (used) at Amazon for a few bucks, a great bargain: