Generally, mistracking is caused by dirty\worn pinch rollers. While some tape types may track ok, some will expose pinch roller issues. Less frequent, are issues like capstan shaft and pinch roller(s), are not parallel. On occasion, a weak or maladjusted solenoid that moves the pinch roller is at fault.
I gather, you are having trouble with a R2R machine, and say rollers-metal or plastic, which I refer to as reels.
When running tape, does it wind into the center of the reel, or does it wind against one of the flanges of the reel? If so, this will cause problems. The adjustment is straight forward, involving removing the case so you can access the lock screws on the reel table, and simply loosen, move the reel table in or out as necessary, and test run some tape, until it spools into the center of the reel. Note, that if you have a 10.5 reel machine, metal reels and plastic ones have different thicknesses, so you may need to use a spacer when mounting a metal reel, if tape is spooling well with a plastic one.