I clung like the picture, but the grip was really fully open, it took the shock all the same, but one day I rode on a small manhole slightly down (I do the racing bike ) and there ... that propelled him into the air, without lying 15m out in front of me, as if he had been placed in a slingshot ...
Obviously, the phone exploded in shock, but the bike mount is well, him.
So, I switched to Galaxy S5 mini, I can not put it in the clamp in longitudinal position, but on the sides of the phone (because the S5mini is slightly longer than the S2). It is well run, but the power and volume buttons interfere a little, so you have to go up the phone on the clamp, so it is not completely centered.
On smooth roads, it held, but on rough (old bitumen, coughed) the phone goes back even earlier ... The last time without paying attention, he slipped gradually up and it was held that by a half-clamp, this fear !!!
So unless you have a cable that grabs the phone, I have no confidence at all in the system clamps and am looking for another solution.
Be careful to measure your smartphone before, because for my case the S5mini is 13 cm, so above the maximum 12cm, so do not rely on the list of compatible smartphones, MAXI 12cm !!