After 2 yrs, the resistance began to weaken. Have to put it above 15 to feel any resistance. Belt is NOT slipping. Little "Resistance Motor" IS working to move "C magnet" nearer to the flywheel. At highest resistance C magnet is about .125" from the wheel. Yet very little resistance and it has been diminishing over the last couple weeks. Called Nordic Track and they said they never had this problem before, but I have seen this complaint in on-line reviews. Machine is useless without resistance.