Originally Posted by theEconomist

Is your 54cm CAAD10 small for you? If it fit great, then you might want to rethink buying this bike. 2 cm in top tube is a sizable change. While it might work, trying to ride a frame that's simply too large is a formula for long term pain.

seat tube fit is easy, just lower your seat post.
To get the top tube fit right, you can do three things (individually or in combination):
1. get shorter stem.
2. move saddle forward
3. Raise handle bar