I.6. Side play of the crankarms
Please see also H.4.
If you hold the left and the right crankarm and try to wobble them in lateral direction, a play can indicate a worn out left industrial bearing (or an inadequate grooved nut on the left side, because it doesn't guide the left bearing correctly: please see F.16.6. for further explanations).
These industrial bearings have a life expectance of 20'000 to 30'000 km.
Such a play can't be adjusted by the self locking nut!