I've noticed when I play TFT with a friend of mine who is much better at the game, I lose almost every match. We are similar ranks right now, but he's climbed much higher than me in the past. When I play solo I feel much more likely to top 4, but as soon as we group up I am back to 7th and 8th place every match, while he wins nearly every game.
I was wondering if there was some hidden MMR component to matchmaking in the ranked queue, or if this is all in my head. Anyone have any insights?
If you win against higher MMR opponents, you will get more MMR; if you lose, you will lose less than if you played against your ELO.
Similarly, if you have a higher MMR and lose to someone with a lower MMR, you will lose more MMR.
All League client games ignore your rank when it comes to matchmaking and use hidden MMR. IIRC when grouped up, it takes an average MMR for the group and tilts it towards the higher end. So if you have an MMR of 100 and your buddy is 200, it might lump you two together as 160ish. Ranked gains and losses are modified by your MMR compared to your rank, but the intent is to bring your rank in-line with your MMR, never vice versa, and the matchmaking doesn't consider your rank.