CX Frame size

[Marcus]

I usually ride a size large for road and mountain bike. Should I stick to the same size for a CX frame or go for a medium as i intend taking it off road but also using it as a winter bike?

[Andrew G]

Same size as your road bike. Don't size on large, medium etc though as they're all different. Go on the effective horizontal top tube length, shouldn't go far wrong that way no matter how they size things. Just make sure that there's enough top tube clearance for jumping on and off easily at obstacles.