Originally Posted by MRT2

A good post except for one thing. If you look closely at a gear inch calculator, you will find the biggest difference between, say, a 10 or 11 speed cassette and an 8 gear cassette is in how closely spaced the bigger gears are, and almost no difference in the spacing of the lower gears. Add to that the fact that the 10 and 11 speed cassettes are more often than not paired with a double chainring while the 8 and 9 speeds are paired with a triple chainring and you will discover that a well chosen 3 x 8 or 3 x 9 is MORE useful for big climbs than is a 2 x 10 or 2 x 11. The reason for this is, when you are suffering up a steep climb, you are using the 3 or 4 largest cogs at the back of the cassette.

So comparing the typical 2 x 11 with a compact double to the typical 3 x 8 hybrid with a triple, the lowest 4 gear combinations on the 2 x 11 are 28.7, 32.8. 36.7 and 41.7. On the 3 x 8 triple with the smaller chainring, the 4 smallest gears are 21.9, 25, 29, and 33. As you can see, the spacing between the 4 lowest gears is about the same on the 8 and 11 speed options, while the gearing is significantly lower on the 8 speed option, paired with a triple chainring. The choice for a person having to deal with big hills should be obvious. The 3 x 8, hands down.