For fun, I thought I'd post my experiences moving to a sub-compact crank. For touring I have a
Co-Motion Deschutes which is 2x11 with compact 32/46 front crank and 11 speed 11-40 rear cluster. I rode this bike last summer and while I was pleased overall I decided (1) I really didn't use the large chain ring very much and (2) I wanted an even lower gear, ideally 28 teeth in front or less (comes with being over 50 years old). So I set about looking for a
Sub-compact crank.
Cycling About has a nice article on lower gears and identified a number of Sub-compact (or compact-plus cranks) but it turns out that none of those met my combination of less than 30 teeth, 11 speed compatible and would fit the 386 EVO bottom bracket.
After some searching, I found that there is a Shimano XT M8000 mountain bike crank which is 28/38. Perfect. And, I could get it for only
$150!. My journey wasn't quite over though. First I had to buy
Wheels Manufacturing crank adapter. Then once I installed the crank I realized my Shimano 105 road front derailleur was too far away from the front chain ring (and I couldn't get it closer without hitting the chain stay). So I bought a Shimano SLX mountain bike front derailleur but this then necessitated buying a
Jtek ShiftMate 7 so that I could shift it with my STI shifter. All in all I probably spend about $300. But it shifts really well now. (I think one could write a separate article on the shift to mountain bike parts for touring)
My Co-Motions Deschutes with a Sub-Compact Crank
At first, the bike looks a little funny with the small front chain ring. But I LOVE IT. I went out for a ride last weekend and finally really used the big chain ring (actually I made better use of the full range). The low gear (28x40) is 18.41 inches
! and the high (38x11) is 90.73 gear inches. For my high gear, at 100 rpm I max out at 27 mph (43.4 kph) which is plenty fast. Anything over 20 mph and I'm probably not going to be pedaling.
With the advent of 11 speed rear cluster with wide gear ranges, I'll go out on a limb and suggest we'll see more sub-compact crank systems (if 1x don't take over). Along those lines I see the following articles
Super-compact chainsets: the next big thing for road cyclists? and
The new sub-compact and the future of wide-range gearing.
I don't mean to start a holy war (like we have sometimes on wheel sizes) but I thought I'd share my experiences. I hope others find this useful.