I suggest you share the sizes of the smallest and largest chain ring, and the smallest and largest sprocket on the cassette, and people may be able to let you know if it is possible to get a derailleur which can select all gears.
Originally Posted by
CliffordK
The Shimano RD-M772 Shadow LONG CAGE is listed as:
9-speed
Chain Wrap: 45T (rear cog difference + front ring difference)
Largest Cog: 36T
Yes, it is an important number. See "Chain Wrap" above. So, for the M772 (and I think the M2000 is similar), one gets 45T (give or take a couple of teeth).
Here is an example project I was working on a while ago. I was playing around with my Jamis Coda a while ago, trying to convert it to a touring/cargo bike.
Rear: 11spd 11/37/42
Front: Dura Ace 7703, 30/39/53
Rear Derailleur: RD-M8000 Shadow (capacity 47T, recommended max sprocket 40T triple, 42T double, 46T single).
Shifters: Bar End: Left: Suntour, Left: ? Shimano.
Above setup capacity: 31T rear (26T to second sprocket) (23T front (30/53), 9T (30/39))
Total capacity: 54T (49T for 53/37, or 40T (39/42))
The M8000 just didn't have enough capacity. I had a choice of the chain going slack on the small/small (11/30), and working on the big/big (42/53), or the opposite, tight on small/small, and not fitting on the larger combo (42/53).
I chose to cut the chain to be tight on small/small (11/30).
I believe that the chain barely stretched to the 53/37 but was to short for the 53/42.
Inevitably I made a couple of bad shift attempts, either shifting up on the rear from 53/37 to 53/42, or shifting in the front from 42/39 to 42/53. In both cases, the chain simply refused to jump up to the larger sprocket. And, within one or two crank revolutions I realized my error and chose different gearing.
So far the derailleur was not harmed (I did do the mis-shifts, but I also try to be gentle).
I was able to do reasonably well friction shifting 11 speeds. However, the derailleur cable pull was too great for the right Suntour bar end shifter's capacity. The ? Shimano shifter was able to be adjusted to pull the full 11 speeds, but was really over-shifting on both ends, and was hard to hold in those sprockets. There is a Microshift Mega 11s bar end shifter that I will try someday which should fix the problem. Or I may try to modify the right Suntour shifter for greater capacity.
I think I did drop the chain a few times on the front, and would like to eventually try a front chain catcher.