PhillB
GT Fan
Nice work I often do similar when a seller doesn't put the seat tube length on an ad. Measure the diameter of the chainwheel (If it is a known one - or count the teeth) and multiply against the tube it's often close enough to tell whether it is a 16 or an 18 or largerI did a quick measure and got this:
Known dimension: Seat tube (centre to centre) 20" (508mm)
Top tube (centre to centre) 23.5" (597mm)
Chainstay 17.5" (445mm) these stays are longer than my 16"?
Stem length 5.4" (135mm)