Originally Posted by
Little Darwin
It is my amateur understanding that the reason modern bike frames use fat tubes is that the strength of any rod/tube is greatest at the outside edge. i.e. a tube with 1 mm thick walls is potentially stronger than a narrower diameter tube with 2 mm walls... and stronger than a very small diameter (say 10 mm) solid rod.
Therefore, my assumption is that the area you want to remove material from is the worst possible area as far as maintaining strength and rigidity.
With the amount of saddle to bar drop you are seeking, I am guessing you are not an easy riding person, so you could be placing significant stress on the stem. Make your decision accordingly.
Now for the smart alec remark that just came to mind...
If you can't get your back flat enough with that setup, have you considered bending your elbows?
I used to bend my elbows in my racing days. OK as a 25 yo. One of my last races was 113 miles. First 60 was going north into a very strong and gusty NW wind. I never straightened my arms for 3 hours. That was torture I wouldn't wish on anyone. Part of my journey into very long stems was to allow me to ride as an older man with my back where I can still ride and my arms straight enough to not be that torture.
Bikes should fit us. We shouldn't have to fit the bike.
Ben