Possibly going to look at a new (to me) bike. It’s a 2018 Cannondale Synapse aluminum 105 SE. The only thing that doesn’t make it “perfect” to me is the mechanical discs, but mechanical vs hydraulic is a whole different topic. My question is sizing. I know I can’t tell if it fits until I ride it, I’m just looking for personal experience with this frame (I’ve read they run big). It’s hard to make this trip with a new born and mine and my wife’s work schedule, so I’m just looking for advice before I even commit to go looking at it. I’m not looking to get told to sit on it first.

I’m 5’11” with a 33”-34” inseam. I thought I’d be a 56, but after reading some other posts I wonder if I should be looking at a 54 because of how these frames are sized? If it seems a little big, would I be ok shortening the stem a little or will that throw off the geometry too much? I’m by no means a great rider, I just want to make sure I get the right bike for me. Funds don’t allow for a new bike, especially with how they’re priced these days, so im working with what I got, which will be used. Any help regarding this frame size is appreciated!