Help understanding geometry comparison for new bike.

Hi There,

Need advice on which size to get on the Cannondale SuperSix Evo. I’m 5’8″ with about a 31″ inseam. I actually test rode and had ordered a Cervelo Soloist in a 54cm. I also rode the Soloist in 51cm, but it was way too cramped for me.

Due to some issues with the shop I had to cancel the Soloist order and am now planning on ordering the SuperSix. They don’t have it available to test ride so I’m trying to use the geometry chart of the Soloist to pick a size for the SuperSix, but it seems like both 51 and 54 have different areas where they match the Soloist.

[Link to the comparison chart](https://imgur.com/a/madZCyf)

Any advice on which i should go with?

by rsapida