I don't think the ranks of the other players even matter, it's what their win/loss ratio is. Eg. In team doubles Your a 30 and have lost no games, your playing with a 30 who has also lost no games (both 100% chance of winning), you somehow are versing 2 50s, but their win/loss is 0.1 (10% chance of winning) so the system automatically predicts your going to win, and if you do win, you wont rank up or rank up that much. If you lose, you will probbaly rank down a fair bit.