Beginner roller skating
Your T-Stop Wheels Should Graze, Not Dig

The T-stop fails for one reason more than any other: too much pressure. Shift your weight onto the supporting leg to lighten the other, then set the free skate down behind it and let the wheels drag across the surface instead of biting into it. Press harder and you get a jolt, and the jolt is what throws you off. Two wheels down or four, it makes no difference. Quad technique, from Najete Kada, a French champion in artistic roller skating.
The T-stop fails for one reason more often than all the others put together, and it is not the reason people expect. It is not timidity, and it is not weak legs. It is that you press too hard with the skate that is doing the braking.
The sequence is short. Shift your weight onto the supporting leg so the other one goes light. Set the free skate down behind it, turned across your line of travel, and let the wheels drag across the surface instead of biting into it. Graze is the word. Dig is what goes wrong.
Press harder and you get a jolt, and the jolt is what throws you off. That is the whole failure: the skate grabs, your speed drops in a step rather than a slope, and the part of you above the waist keeps going at the old speed.
Two wheels down or four makes no difference, so stop worrying about which. The pressure is the variable that matters and it is the only one worth practising. Quad technique, from Najete Kada's Tuto roller series. She teaches quad skating and skates it herself; nothing on this page is a claim about inline skates.
Keep going: this is one section of the full Roller Skating for Beginners guide — sizing, gear, stopping, and where to skate, in one page.