Maybe on a recumbent, but on a DF road bike a 145mm crank just cannot be something the o.p. should consider. If he should, then we all should. Well certainly all women... I mean... he's 5'8" not 5'2", and there are plenty of 5'2" women using 170mm cranks. Raise the bars. Simple. There are head tube extenders. That is what is needed, not a longer stem.