New bike sizing advice

Hi all, I am seriously considering getting a cx bike but i am struggling to decide what size to go for.
I usually ride mtbs but i used to have a road bike for a short time a few years ago.
I am currently looking at the Cube Cross Race but my height is the top end of the smaller size and the bottom end of the larger size (53 vs 56)
The road bike i had was a 52cm and it was too small so that's why i am nervous about getting the 53cm Cube.
My mate has mentioned that people usually go for the smaller size than a road bike but it's a lot of money to not be right.
I am so busy with work and having a newborn means i can't easily get to nearest dealer and have a sit on one.
Hopefully some of you can point me in the right direction.
Thanks
Matt
I usually ride mtbs but i used to have a road bike for a short time a few years ago.
I am currently looking at the Cube Cross Race but my height is the top end of the smaller size and the bottom end of the larger size (53 vs 56)
The road bike i had was a 52cm and it was too small so that's why i am nervous about getting the 53cm Cube.
My mate has mentioned that people usually go for the smaller size than a road bike but it's a lot of money to not be right.
I am so busy with work and having a newborn means i can't easily get to nearest dealer and have a sit on one.
Hopefully some of you can point me in the right direction.
Thanks
Matt
0
Posts
Cross bikes have bigger clearances for the tyres and mud room, so the top tube will be higher above the ground, than a road bike with the same geometry, reducing nut room.
Some cross frames have less of a bottom bracket drop than others (to increase ground clearance for the pedals) although many modern frames are now approaching the more typical road type drop of around 70mm.
Looking at the cross race geometry then it was a 68mm drop, so pretty much like a road bike. The top tube is 554 mm. At a rough guess I would say that it would suit a rider of around 5 foot 11.