Any shimano mountain rear derailleur labeled as 9 speed should work. Those labeled 10 speed or dynasys will not. XT derailleurs rd-m770 (rapid rise), rd-m771 (normal), and rd-m772 (shadow) will all work. For a touring bike, I’d be inclined to go with the lx one you posted because it has a barrel adjuster, whereas the xt ones do not.
Technically shimano lists the max cog for all those derailleurs as 34 but you should be able to play with b tension adjustment to get a 36 to function acceptably.
Edit: whoops. actually rd t-661 lists a max cog of 32. Ive seen them work fine with a 34 but 36 cog is maybe not a great idea?
Thanks. I have a barrel adjuster at the cable stop on the frame so that’s not an issue. I don’t want rapid rise and people on MTBR complained a lot about the shadow version, but the m771 is a possibility. Would it be a meaningful upgrade over the LX? It’s only marginally more expensive in one shop.
If you’re set on running a 36, I’d go xt, due to it being rated for a larger max cog.
Yeah I need the 36t to climb the occasional big hill with loaded panniers. It’s a bit of a freak setup but it’s less embarrassing than walking up a hill, right?
Thanks for the info.
Also, maybe get the mid-cage version of the XT which I’m pretty sure will handle 36t plus a double. The long-cage LX that I have is a little slow at taking up the chain and sometimes I get chain suck.
Chain wrap capacity of the mid cage dangler, per shimano, is 33t.
(50-34)+(36-12)=40t
Probably ought to stick with the long cage.
Shimano is ridiculously conservative about that shit, you can fit a 32t without thinking about it in all those danglers rated for only 27t
if you have the barrel adjuster elsewhere, get the XT M772 GS
GS? As posted above, shimano says I need the SGS. Of course I don’t give a shit if the chain droops in the small/small combinations I’ll never use, but will the GS shift better or someshit?
Yes, it will, by virtue of having a shorter cage it will shift more quickly and be less likely to cause chainsuck.
This is the longest DQ thread where no one has pointed out that it’s a DQ thread in tarck history.
Eh, I think it merits the discussion.
Thanks for the advice, people. I ended up getting a 12-36 Sram cassette and an XT (rd-m772) dangler. After some fiddling with the adjustment settings, shifting is now better than it ever was with the original 11-28 and short cage 105 dangler.
34/36 worked out pretty well on Stelvio Pass, too.