http://www.competitivecyclist.com/za...LCULATOR_INTRO

Do a road fit, probably tending towards the French Fit, if you want a classic touring frame. But either way, what you are looking for is whether the seat tube and top tube are pretty close. In my case they were four inches appart. So 56 and 60. To me that begs for a custom frame. but I was never uncomfortable with the 58 I had. However if I had gone with a standover fit, a 56, then the added 5 inches of reach would have been a bit much for a stem to take up!

On the other hand, this fit calculator was easy for me to read. But... it did recomend everything from 53 inches to 61, if you take my shortest leg fit, and my longest TT fit.

But getting back to the custom question, if your numbers came out 58 leg 52 reach, because of ballet dancer like leg length or something, then you would know the custom option is reasonable. If your fit comes out 56 56, then you fit off the rack. So goign through the process will tell you whether you are a necesarry custom fit person.

You don't need a custom bike for any other reasons than: 1) fit 2) pretty 3) you have a ton of strong opinions and you need a way of getting them into a frame: 9 water bottle mounts, and a 20" wheel in the front.