(Nice looking De Rosa!)
What changes do you want to make from your current bike? Are the bars too far, so you are stretched out and you always seem to pull your hands back from the hoods? or what? with a range of bar position changes, you can see if the new bike is marginal or if it has room for adjustment after you ride it.
I'm still riding that 2014 bike mentioned in my posts below! It's still exactly what I want. I have the top surface of the bars set about 1 1/4 inches / 30mm below the saddle top. It's great: the drops are very comfortable and usable. I probably ride 50% hoods, 40% drops, 10% tops. So many riders rarely use their drops -- the bars are really too low for them. Drops advantages: A little more aero. Much better control on bad roads, and more comfort on bumpy roads with the shocks spread out across my palms. My back is stretched out a little in the drops--nice.
How to compare bike geometries
From
another thread, I posted:
I found it hard to compare bikes, since they don't always measure the same way.
Stack and reach worked great when I bought my new road bike in 2014. Some bikes were 53cm, others 55cm with very similar stack and reach numbers. The old bike fit was pretty good, so I used it to find similar fitting bikes. The goal was to have maybe 20mm of spacers under the stem, to allow later adjustments either up or down. After 30,000 miles, it still is set at 20mm!
Here's an easy way to
measure stack and reach for your current bike.
And the first link mentions a nice
stem angle comparison tool--very useful. This makes it easy to see the net effect of angles along with stem lengths. Helpful to adjust from an ill-fitting frame with a very short or very long stem to a better frame with a normal 90 mm to 110mm stem.
I ignored seat tube angle. I'm guessing that most road bikes seat tube angle differences won't really affect the saddle clamp placement very much.
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The "measure stack and reach" linked post uses this measuring method:
https://www.bikeforums.net/19803742-post21.html
Measuring Stack and Reach
Bike rear tire against a wall.
Stack is the difference between the two vertical measurements.
Reach is the difference between the two horizontal measurements.
(convert inches to mm with google search, like this: 21 5/8 inch in mm)
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One more thread, mentioning how the bike stem calculator works:
https://www.bikeforums.net/18957455-post17.html
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