Hey all, I was recently involved in a traffic collision that totalled my bike, and I'm currently shopping for another frameset. I'm a little confused on stack/reach, having only mostly dealt with top tube length since previously I only rode more classic steel frames. I used a geometry calculator to establish stack and reach for my previous frame--a Lemond Zurich and have found that contrary to what I assumed I would fit (a size Medium with ~54cm top tube), the stack and reach seem to suggest that a size Small frame would better replicate my old fit. Does that seem right? My bike is in the shop at the moment being assessed for insurance, but I believe I am set up with a BB to Saddle measurement of 74cm, and Saddle to Bar drop of ~14cm.


Should I be aiming to replicate stack and reach exactly--or should I be doing something else?

If you were fine with that low (aggressive) stack height on the Lemond, then go for the BH Ultra as the stack is only 5mm taller (run less spacers). Reach is only 4mm longer (run a 5mm shorter stem).

Frame standover on both bikes looks similar; so that's good.

Going to the Strato would be like getting a relaxed fit for you, as it is 29mm taller at the front.

I would use that tool to estimate how you can get a given frame to have approximately the same reach & stack as your old frame. take the calculation with a grain of salt and know that you might have to tweak it with the stem position to get it just right. play around with the stem length, angle, and spacers to see what it would take to get the handlebar to the same "reach" and "stack" at the bar.
then consider the seat tube angle. unless the STA on two frames is identical, the saddle position you end up with might be a little different from your old one relative to the handlebar on your old setup.

in case you were basing your standover height comment on the graphic above, that's not the standover. that's the effective top tube. I love that bikegeo tool and use it all the time for bike thought experiments and the occasional purpose. I think it might have been possible to program it so it shows actual top tube, but on every bike, it shows a horizontal line of the ETT. the standover of those bikes might be vastly different.

Did you include the headset stack in your Lemond calculation? External headsets add 20-30 mm to the measured headtube length.