Ok thx, I will go on my atelier and check out if I´ts a wrong montage install from me, or simply that I was not delivered, think I remember seeing a spacer but it was a black plastic one but it slide between the cogs and definitly not this small metal one, I could vampirise my cheap road bike and see if I find one.

Edit; Nope no spacers I will have to buy one the black one is just a spacer between cogs nothing more