As above I’m unsure which I should buy.

The set up will be –
Double front 26/38 with an 11-36 rear cassette

The GS says it has a limit of 35T so does that mean I’ll need an SGS? Would the SGS be better anyway? Are there advantages to running one rather than the other on my set up?

I have run an XT and SLX GS mech with a 22/36 and 11-34 which is the same 37t total you are wanting. The cage was long enough to take up the chain. Shimano mechs are often fine beyond the spec.

GS mech is much neater and less likely to get hit…plus looks better 🙂

Capacity = (Biggest front ring – smallest front ring) + (biggest rear cog – smallest rear cog)

So yours is:

(38-26) + (36-11) = capacity
12 + 25 = 37T Capacity

I’d suggest that a SGS would be the correct setup but you might probably get away with a GS is you avoid the ‘top’ gears, but then as your limiting yourself to two rings, this might not be the best idea.
I thought the whole point of running a GS (other than the capacity) is that it doesn’t stick out as much, so it less likely to pickup crap and break…

Thanks both of you.

I was trying to work out the capacity bit and had confused myself but it’s clear now.

So I could get away with GS but SGS is what Shimano would recommend for that set up.

Not related to rear mechs,but any chance of dealing with the refund for the light delivered back to you on saturday? I
emailed yesterday to chase but have not had a response.