  One of the puzzles in the recent observations of gravitational waves from
binary black hole mergers is the observed low (projected) spins of the
progenitor black holes. In two of the four events, GW150914, and the recent
GW170104, the observed spins are most likely negative (but consistent with
zero). In the third case LVT151012 it is practically zero and only in the forth
case, GW151226, the spin is positive but low. These observations are puzzling
within the field binary scenario in which positive higher spins are expected.
Considering the most favorable Wolfe Rayet (WR) progenitors we estimate the
expected spin distribution for different evolution scenarios and compare it to
the observations. With typical parameters one expects a significant fraction
($\ge 25\%$) of the mergers to have high effective spin values. However due to
uncertainties in the outcome of the common envelope phase (typical separation
and whether the stars are rotating or not) and in the late stages of massive
star evolution (the strength of the winds) one cannot rule our scenarios in
which the expected spins are low. While observations of high effective spin
events will support this scenario, further observations of negative spin events
would rule it out.
