Originally Posted by
jimmuller
I'll weigh in on the compact double setup. Long before anyone called them that I had set up my bikes with smaller rings. ... the 110BCD gave my a cheap path to lower gears. Also with smaller rings and smaller FW the bike is lighter that using a larger FW.
The point was, I almost never used the 52/14 combination for either sport riding or commuting, and I certainly never needed it. But I was always wishing for lower gears. So why not trade off one big combination for one little one?
Stronger chains, cogs, and chainrings made reduced tooth combinations feasible, although even today, for a given ratio, more teeth will mean greater driveline longevity.
When I worked at a Peugeot/Nishiki dealership in the early 1970s, almost everything, whether for touring, recreation, or racing, came with a 52/14 = 100-inch top, although Bianchi often went as high as 52/13 = 108, and Nishiki thought 54/14 = 104 would be a good idea. After 50+ years of experiments in "gear phreaking" and 100K+ miles on the road, I have concluded that, for me, a top gear in the mid 90s to very low 100s, with a corresponding top cranking speed of just over 30mph/50kph, is perfectly adequate. Since I also want a bottom gear in the low 40s and about a 6-percent ratiometric progression, I cannot afford to waste valuable cog/chainring combinations on stratospheric mashing gears. My road bikes, all 12-speeds, have highs of 45/13, 47/13, 49/14, and 50/14 and lows of 42/26, 38/23, 46/26 (admittedly a little too tall at my age), and 42/26.
The secret to avoiding cross-chaining with a compact crankset is either to do a close-ratio triple (48-45-34/13-15-17-19-21-24, for example, a very nice 40-to-100 range which works with a standard short-cage derailleur) or to use a 1.5-step pattern, in which the ratios on the large ring interlace nicely with those on the small ring, e.g. 46-38/13-15-17-19-22-25-28.