SquireBlack 

I'm building up a new touring & camping bike. I have 44-26 chainrings, and a Shimano 11-36 9-speed cassette. Since Shimano makes that cassette, I had assumed that they also make a rear derailleur that will work with it.

Which one? There aren't that many available. The RD-M591 Deore SGS is one, and it even comes with a silver body (as an alternative to the gloomy black). But the advertised big cog is 34t. I know that often Shimano RDs work fine outside their advertised specs, but since I'm buying new, I figured that I might as well get one that is actually spec'd to work with the 11-36.

My total capacity is 43t, which means that I'll need a long cage. I've tried an (almost new) 10-speed 105 RD-5701 (Shimano 10-speed road RDs have the same pull ratio as 9-speed), and it doesn't work, predictably since it's specified max cog is 30t. I've sort of got it working using a worn out Deore XT RD-M750 with the B-screw replaced by a cap-head screw put in backwards, but that's not an acceptable final solution.

What's the right answer?

urbanknight

Plenty of M592 derailleurs out there. 36t max cog, 45t max capacity. The M591 would probably work as well, but it sounds like the M592 is more certain and about the same price. Can't help you with the color on that one though.

Bill Kapaun

3x9

Andrew R Stewart 

I just installed a 12/36 9 cog cassette on my touring bike with it's M-591 rear der. On the stand it works fine, although the "B" pivot screw needed a fair amount of turning in. My experience suggests no real world riding issues. Shimano can be somewhat conservative in their claimed capacities. Of course some of this also depends on the bike's hanger length and I build my touring bikes with long ones for this very reason. Andy (the rings are 24/34/44)

shelbyfv

I'm using a 9 speed T661 aka LX derailleur with a 10 speed 11-36. It clears the big cog w/o any b screw fiddling. I don't know what the specs were. 46-30 crank. I'd bet an M591 would work as well.

SquireBlack 

Thanks for the advice. The M592 is a "Shadow" version, which seems to mean that it lacks a barrel adjuster. This isn't a fatal flaw because I have an adjuster in the headtube stop. I've ordered an M592 — amazing how hard it is to find parts in stock right now.

I suspect that the M591 would work too — and if it didn't, then it would have with the addition of a Wolf Tooth Goat link to extend the hanger. My hanger measures about 26mm from the axle center to the hanger bolt center. I wasn't aware that hangers came in different lengths — I chose my dropouts because of the rack and fender eyelets, and because the angle between the stays was close enough to what I wanted.

SquireBlack 

While I was placing my order and writing that post, @shelbyfv posted the picture of the "9 speed T661 aka LX derailleur". I really like the looks of this! I would cancel my order and go with one of these ... if I could find one!

BicycleHero has something that they call a T661 on their site, but it looks different, has a claimed max cog of 32t, and is out of stock.

alcjphil

What shifter?

shelbyfv

Yes, I'd be surprised if you could still find a new one. They were part of a 9 speed "Trekking" group that was never officially available in the US. There was also a nice compact triple HT2 crankset. IIRC, I bought several of the derailleurs from an ebay seller (BikeWagon?) about 10 years ago. This was the last unused one.

cyccommute 

An alternative is to use a Wolf Tooth RoadLink. I have used one to extend the range of a 9 speed XTR rear derailer for use with an 11-36 cassette. Works very well without having to set the B-screw to severe limits. I have zero issues with using it.




By the way, Shimano’s capacity numbers are extremely conservative. The RD-M970 SGS derailer I’m using is supposed to have a maximum capacity of 43 teeth. In that picture, I using a 48/36/20 crank with the 11-36 cassette which puts me at 53 teeth for capacity. The system works without issue. The chain can be a little slack in the little/little combination but I would never use that gear anyway. I’ve recently reduced the largest chainwheel to a 44. Wrap is still over Shimano spec at 49 teeth but it still works.

The RoadLink, by the way is $22 which is much cheaper than a new derailer.

Chuckles1

I put a Sora (RD-3000GS if I recollect) on my 9 speed when I changed 12/25 to 11/36. I believe an Alivio would work as well. The Sora shifts "like buttah" BTW.

tommymc

I am running an M592 on a 11-36 10-speed cassette. My only problem was to find a flat bar (Velo Orange Crazy Bar) shifter for this combo. The only one I came up with was a Tiagra 4700. It worked but needed frequent trim adjustments while riding. Apparently Shimano changed the pull length a little on the 4700 in midstream of 10speed Tiagra group. Interesting how the ever improvising Microshift folks even make shifters specific for that orphan group. So in a last resort I've moved the shift cable's anchor point to the opposite side of the bolt using some improvised washers, Shazam! It works fine now. I think the M592 is a very versatile RD that will work fine with any Shimano 9-speed shifter and the right 10-speed shifter as well. It's probably not made anymore. The pre 10-speed Deore stuff was so good for touring setups. Now we have to hit a curve ball.