Thank you, Anthony. I had a notion the two frames would be similar based on reach (38.6 vs. 38.7 cm) but I didn't realize seat tube angle, for instance, would have such an effect from such a small difference (.5 degree).
What worried me about "54" was the effective top tube length, it was at the very end of the range that different bike fitting sites would give me. Then again, "french fit" at competitive cyclist gave me roughly that number (548). Please bear in mind my seatpost has a 2 cm offset.
Won't I be too stretched out on the bike because of that length? Should I get maybe an 80mm stem for this build?
Also, about "52": can I get a similar fit to "54" with a higher handlebar position (using spacers)? I ask because most bike fit programs tell me I should get something with 53.5-54 cm top tube, but maybe that's for a more aggressive position and I'm looking to ride more relaxed right now as I ease myself into road bikes. I just don't know much about this!
Originally Posted by
AnthonyG
Based on your lack of flexibility I would recommend the 54cm frame. It has a more relaxed seat tube angle by half a degree and a taller "stack" or head tube length. The higher stack means you don't have to reach down as low for the handlebars.
The 52cm frame isn't really that much smaller than the 54cm frame. The biggest difference is the steeper seat tube angle which is a fudge really. The 54cm frame is more honest.
The discrepancy between the actual seat post length and the nominal frame size comes down to the sloping top tube (compact) design. The frame is sized as if the top tube was level. This is actually the right way to do it otherwise the sizing would be misleading Don't be concerned about stand over clearance. Its nice if you have it but its not the right way to size a frame.
Anthony