Originally Posted by chas58

I think Zaskar may be right.

I'm 5'9" (177cm) with an 86cm inseam (pressed hard against my pelvic bone). Normally I ride a 54cm frame, but for Canyon (Inflite), I'm a small. The size chart for the grail and inflite looks to be the same.

Ideally I would have gotten a medium with a short stem, but since I got the Inflite the top tube was too high (and a shorter stem cost $400), so I kept the small. I've been quite happy with it, although the medium would be a little more stable and offered a little more stack. The small has a little less reach and a little less stack than I'm used to, but I love it. It fits well and is a ton of fun.

You can goof around with their calculator, but my height is the only thing that seemed to change the frame size for me.

I'm rather between sizes. I think you would be fine on the medium.