I see this type of comment often when someone is asking questions about drop-bar conversions. Doing a DB conversion doesn't have to be an "invest a bunch of money and time and only then see if it fits ok..." adventure.
If someone has a drop bar bike that fits well(or even a flat bar bike), everything is known with respect to how the fit of a flat bar bike will transition to a drop bar bike.
Step 1) Measure the frame and handlebar stack and reach of the good-fit road bike.
or
Step 1) Measure the frame and handlebar stack and reach of the good-fit flat bar bike.
Step 2) Use the stem comparison site to estimate the handlebar stack/reach impact of various stems available.
Stem Comparison Tool | yojimg.net
Step 3) Use the specs on compact drop bars (typically 75mm reach and 125mm drop) to estimate the handlebar stack/reach of the drop bar converted bike.
Step 4) Compare the handlebar stack/reach to the good fitting second bike. In my case there isn't one specific stack/reach combo that I find comfortable, rather there's a fairly wide range of stack and specifically reach that I find comfortable. If you can't find parts (a stem, usually) a DB convert-candidate bike needs to get the conversion into a comfortable stack/reach range, then the candidate bike isn't good for a DB conversion.
The key is flat bar bike a shorter than average top tube. For example, the 1990-1993 Trek 900 series mtn bikes have a shorter top tube than 1994 and up.
My touring bike is a '93 Trek 970 with a DB converted handlebar stack and reach that is very similar to my road bikes. Similar enough that I can ride 50 miles a day for a couple weeks and have no fit issues at all. It's a wonderful touring bike.
This is a recent DB conversion on a Trek 7.5FX (WSD) for my partner. I've done two of these for her. They've been really nice bikes. First, they fit And they run fast 38mm tires with plenty of gearing to handle about any terrain.
