19.5 X 2.54 = centimeters. or 25.4 millimeters. it comes out to 49.53 cm or 495.3mm. How tall are you?
I would do a couple of personal measurements.
Inseam
Take a book, shove it as far up as it will go between your legs. Stand with your back against the wall and measure in your barefoot feet. Top of the book to the floor.
Thigh Length
Pelvic bone to the top of the knee (good to have but without the bike, hard to tell if you have enough clearance)
Arm Length
Next Measure your arm from the bony part at the top of your shoulder to the middle of your open hand.
Torso Length
Measure from your crotch to the bony part below your neck.
Shoulder Width
Measure from the bony bump of the outside of the right shoulder to the bony bump to the left side.
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Bike Measurements
Ask the person to measure the bike from the floor to the center point in the top tube. Compare that with your inseam. Even though you will be wearing shoes, you want 1-2" of clearance.
Next have him measure the c-t-c top tub length. (19.5" may be correct)
Next have him measure the stem length (usually average 100mm or 3.9 inch) (if at an angle use a ruler and mark the effective length)
Finally have him measure the handlebar width. (convert to cm.)
Top Tube/Stem Measurement
Combine the arm and torso measurements take the inches X 25.4 = your combined arm/torso length. Compare that to the ctc top tube length+stem length combo. If it is off a little you can change the length and angle of the stem.
Example: if the top tube c-t-c is 495.3mm and your stem has an effective length of 100mm = 595.3 if you are close good but if you are more than 20mm, depending on the stem length and if the stem is at 90 degrees versus an angle, I'd say pass.
Stand Over Height
If there is too much clearance or too little clearance in standing over height, pass.
Shoulder Width
Compare the width of the handlebars to your shoulder width. Most men are 42-44cm on a touring bike.
Shoe Clearance
with 18" or 457mm in the chain stays, unless you have size 13+ shoe size or very wide bags it will work.
This is far from perfect, but will give you a general idea of what will work or not work.
