Long, Med ,Short Mech?

bmxboy10

Hi can anyone advise me what rear mech I need? I am building a bike with 52/36 Chainset and a 11/28 cassette.

Its all 105 5800 but am confused about compatibility with the semi compact chainset and this cassette.

Grill

Short. You can go medium if you plan on using a cassette with a 32 bailout cog.

sloppyschleckonds

If you plan on riding abroad think about a medium cage even if running a 28 cassette, there is no shame in using a 32 or 34 cassette especially if running a 52 x 36 and it'll save you changing mechs later