Geometry god's.......
Nordest Albarda with an already high 85mm BB drop giving a low BB. Designed around 700 and 650b wheels but, by my rather rough calculations, the change from 700x45c to 650x2.1 is going to drop the BB a further 10mm ish, give or take.
For mainly rough roads, smooth single track and gravel tracks can you forsee any issues?
I don't generally pedal through corners and am conscious enough of crank positioning.....
85mm or so is about as low as you can go with 700 x 35 or 650 x 47 (685-690mm OD approx) and average 175mm road/gravel cranks + SPDs and still meet ISO lean angle / pedal clearance rule. But that's just ISO for a full bike. With 650 x 47 tyres your BB will be ~257mm off the ground, std road bike is ~265mm. MTB cranks and flats will be a fair bit snaggier than narrow-Q road cranks and SPDs.
I rode a bike with just under 260mm BB height for a while, a 700C bike converted with narrow 650Bs, you needed to be careful pedalling out of a roundabout and roots off-road were a PITA but it was great everywhere else.
