Just been looking at the 1170 cassette. Might give it a try, certainly be a cheaper option than new cassette, mech and tanpan thingy.

Let me know if it works. 🙂

I would love to keep the 50/36 chainrings I use for commuting and training and then stick the 11-36 in for off-road adventures.

Quick update for those with a 2×11 setup. Just fitted a sram 1170 11-36 cassette with a ultra 50-34 chainset, 105 rear mech and rs685 stis. All works fine so far even in 50-36, although the mech looks at its limits. I might put an extra link in to take a bit of strain off. Certainly workable though.