i think it might be too big depending on your inside leg.
I am 1.78 and went for the 53 and is perfect. CX have different geometry than road bikes and due to the nature of the cycling you will do (if you go off road) most people go for a size smaller other than larger.
Although a 53 would be small for you, you may wish to consider a 56. Compare the geometry of top tube of your current road bike if you have one and the Cube.
Im very happy with mine, did two Duathlons now one in mud as above and one in snow (on Sunday) and it served me very well.
Thanks for that. I was looking at the geometry on the cube website and the centre to centre length on the seat tube was listed at only 540mm and I was concerned about it being to small. My inseam measures at 59cm so I reckon I should be pretty close. The top tube on my Trek Madone is 580mm but the top tube on the cube is listed at 560. Geometry is a tricky thing in bikes and it always pays to talk blokes like yourself who are riding them. They are so new there are hardly any reviews or opinions on them. I want mine as an all weather commuter with some occasional trail riding thrown in. Can't wait!
Thanks again,
Mark