Wayne Dalton Garage Door Resistance/Tugging Problem

Hey guys,

After 10 years, our Wayne Dolton Garage door broke a spring and couldn't hold itself up anymore. So I fixed it myself and everything was great again. 

A month later, the garage door seemed a little noisy and after a complete inspection I finally saw the problem in the chain. One side was all slack and the other all tight and I knew it needed to be balanced out. It was the slack part of the chain wacking the rail as the garage door went up and down and the hinges needed to be greased up for squeaking. I adjusted the chain and balanced them out and then tightened them from the opposite end. 

The garage door ran smoothly, no squeaking, just a nice hum of the motor. 

A month later, the garage door is tugging. You can see it as it opens and closes, it goes up and down but its tugging instead of a smooth transition. I don't know what it is, I manually lift the door to check the spring tension and it liftable and holds itself. But half way up it gets harder to lift.  I checked the cables to see if they were wrapping correctly and they are and I checked rollers, but they nylon and don't appear to have ball bearings and have a very slight wiggle but nothing that screams replace me!  I don't know how well they spin unless i remove one but i can rotate them with my finger so I wouldn't think its causing a lot of resistance. 

So I don't know what's going on, where this sudden resistance is coming from that is causing visible tugging/jerking motion. Maybe its times to replace the rollers, idk whats your opinion guys?