I'm trying to compare the frame measurements of a cross bike i sat on today (a Scott CX comp 54cm) to my road bike (bianchi 928 carbon 53cm) I really just want to compare the top tube lengths and seat tube + standover heights.

bianchi (its the 928 carbon one)

scott cx comp

The bianchi pic doesnt seem to have a measurement from BB centre to toptube centre, but it has another measurement marked A1 but i'm not sure exactly what this is measureing 😳

If i use B1, BS and the angle G2, can i use this and some trig calculations (i'll have to look these up cant remember how to do it!) will i be able to work out the short side of the B1 BS triangle, and if i subtract this from AS i'll have the BB to top tube centre length??

Still wont give me the standover height though…

And i before anyone says just meausure it, i cant as the bikes not here at the moment 🙂

take a guess

Yes, it's fairly simple to work it out (not exactly the way you've described though) but surely AS + BB height is close enough..

s'pose it depends how acurately you've measured ball sack drop too though 😛