Has anybody not carry their spare tire?

It will stay in your tire as long as you leave it in there. I have been running it for @ a month and have no balance issuses at all. I was concerned about that before I put it in. The only problems I have eperienced is on sub 30 degree weather the stuff freezes, and the first mile or 2 you can feel it in the tires(slight shimmy) but breaks up quickly and shimmy goes away. I used the chart on the back of the bottle and for the size tire I went with 2.5 bottles per tire.