welchy wrote: ↑
Thu Jul 04, 2019 5:05 pm
tommasini wrote: ↑
Thu Jul 04, 2019 4:54 pm
I’m with joeyb1000 (and others) who are hoping for a flat lander cassette option.....something like a 12-27 or 12-29 would be awesome. The current 11-29 12 speed is much less appealing than my current 12-25 and 12-27 11 speed......such that I’m not buying 12 speed until that happens (if ever?)
You should try 11-32 (52-36) the best setup I’ve ever had, ridden flats in UK to Pyrenees. Perfect.
The 11 speed 11-32 spacing is 11–12–13–14–15–17–19–22–25–28–32. That means that if you only need a 12-25 for the riding that you are doing, you are effectively downgrading from 11 speed to 8 speed
by switching to an 11-32.. (12–13–14–15–17–19–22–25), or to 9 speed
if you switch from an 11 speed 12-25 to a "12 speed" 11-32.. You get much bigger jumps between the gears, with the added bonus of carrying around a significant amount of extra weight..
Even going from an 11sp 12-27 (12-13-14-15-16-17-19-21-23-25-27) to a 12sp 11-29 (11-12-13-14-15-16-17-19-21-23-26-29) you are not gaining any more useful sprockets (arguably you are still losing one) while getting larger gaps at the dinner-plate end.
Obviously bigger sprockets are useful in the Pyrenees, but for me at least, if they aren't useful whatosever for 95%+ of my riding then I'd rather switch cassettes for trips to the mountains once every two years or so!
I know I'm repeating myself on this thread but I find it staggering that we worry about 1 or 2 watts of drivetrain efficiency, 2.5 millimeters of crank length, barely perceptible improvements in shifting efficiency etc, but that few seem to care about the relationship between optimal cadence and gearing, i.e. the fundamental interface between biomechanical and mechanical power. Even just a single sprocket shift in the middle of the cassette equates to a considerable difference in cadence at a given power, e.g. at a dead-constant 225w my cadence is 85rpm with a 36/13 and 92rpm with a 36/14. With bigger gaps in other parts of the cassette you are easily
talking about cadence differences of 10+ between gear shifts. Does anyone really think that being forced to maintain a cadence of 100 instead of 90, or 70 instead of 80, isn't going to result in biomechanical efficiency losses? Of course what happens is that you fudge it by finding a compromise between power and cadence (e.g. you might lower your cadence by 5 and increase your power by a few watts at the same time after shifting to a sub-optimal gear), but that's just trying to mitigate the efficiency losses that you can feel..