Ranked 3v3's and 5v5's

So my friends and I decided we should create a ranked 3's team. This morning we wanted to continue our placements and realized we couldn't play them. If 3v3's and 5v5's are in a different queue (not the dynamic one), especially for 3's, why can't we play at any time. Why does there have to be a 6 - 8 hour window for ranked 5's which only allows ranked for 3v3 in those times as well. ANYWAYS ITS USELESS TO PLAY NORMAL 3V3'S BECAUSE EITHER EVERYONE IS A BOT or of a very skill desparity!!!