  The goal of this paper is to investigate Reynolds stresses and to check if it
is plausible that they are responsible for angular momentum transfer toward the
solar equator. We also analysed meridional velocity, rotation velocity
residuals and correlation between the velocities. We used sunspot groups
position measurements from GPR (Greenwich Photographic Result) and
SOON/USAF/NOAA (Solar Observing Optical Network/United States Air
Force/National Oceanic and Atmospheric Administration) databases covering the
period from 1878 until 2011. In order to calculate velocities we used daily
motion of sunspot groups. The sample was also limited to $\pm$58\degr in
Central Meridian Distance (CMD) in order to avoid solar limb effects. We mainly
investigated velocity patterns depending on solar cycle phase and latitude. We
found that meridional motion of sunspot groups is toward the centre of activity
from all available latitudes and in all phases of the solar cycle. The range of
meridional velocities is $\pm10$ m s$^{-1}$. Horizontal Reynolds stress is
negative at all available latitudes and indicates that there is a minimum value
($q\approx$ - 3000 m$^2$ s$^{-2}$) located at $b\approx\pm$30$^{0}$. In our
convention this means that angular momentum is transported toward the solar
equator in agreement with the observed rotational profile of the Sun.
