Sooo I had made a long reply about some crazy man maths before the iPad died..
Let’s assume my current frame could take 275 wheels and fork. The bfe26 has a 17.6mm drop with a 140mm fork at 25% sag. Let’s call the current BB height ‘X’, as I don’t know what this is.
If we put 275 wheels into my frame, this will increase the BB height by around 15mm. If we put a 275 140mm fork into my frame, this will increase the BB height by another 10mm or so. So, to achieve ‘X’ you would need to drop the BB by a further 25mm or so, Totalling to a 42.6mm BB drop. With 140mm forks; The soul has a 38mm drop, the Slackline 51mm.
This means the Soul with my 26 gear will have a bottom bracket height which is 20.4mm lower than my current ‘X’.
The Slackline with my 26 gear will have a bottom bracket height which is 33.5mm lower than my current ‘X’.
Given that either of these frames could be run with 100mm fork and 2.2 tyres, the difference could be even smaller.
Given a couple other 26 dedicated frames have a lower BB than my bfe (BTR ranger has a BB drop of 42mm which is 25mm lower than my current bike!)
Man maths gone crazy?