Joined: Aug 2006
Posts: 5,705
Likes: 2
From: Hot as hell, Singapore
Bikes: Trek 5200, BMC SLC01, BMC SSX, Specialized FSR, Holdsworth Criterium
That's a great choice to have.
For me a test ride is at least 40-50km. Mix of the type of riding I will be doing.
A ride around the block isn't going to tell you much.
Not everyone will let you ride that long but that will also tell you about the LBS. To be fair not all LBSs are going to have your size available for test.
If you already have your own saddle and pedals then take them along.
Your heart will tell you as much as your head.
Choosing a new bike is a good "problem" to have!