My B50 with the plastic tension bar bushings still needed to be jostled every once in a while after using it to return to zero. It already has tusq nut, roller trees, roller bridge, and i had tried teflon dri-lube on the roller bushings with no effect. Shot some Liquid Wrench brand silicone spray in there the other day after covering the finish really well and its damn near perfect. Didn't even need a heavy spray, just barely depress the sprayer with the spray tube right on the seam of the bushing and frame and it sucks the silicone down onto the bar. Of course this was the day after I ordered the BiggsFix replacement with roller bearings .