Used to be a fab shop here in town that made odd little bits for Cup Car teams (like an engine hoist hook that swiveled on a 9" pinion bearing inside of a trick looking o-ring sealed billet aluminum housing) and I got to know the guy who did most of the one-off fab work fairly well. He told me of when 200 mph became common on the big ovals that the RF outer wheel bearings rarely could handle the load for that long. They were to the point where they'd buy a case of them at a time, and do all sorts of pre-use testing on them (no idea what they actually did). After sorting thru the whole case they might have 2 or 3 candidates that would go the distance. the team that he worked for at the time brought in a Tribology specialist who looked at the lubes that they used for everything in the race car and one suggestion that he made was for them to switch to CV joint grease in the front wheel bearings. Prior to that they had been using a premium, but typical wheel bearing grease.
The CV joint grease took the situation from the whole crew (& driver likely!) praying that the bearing would last the duration of the race to the bearing looking like it had another race left in it afterwards. He told me that when synthetic CV joint greases became available they switched to one of them and the bearing life got even better.
Then DuPont's Krytox grease made the scene and they were able to significantly relax their bearing screening process. Mere mortals can't afford to run Krytox in anything, but since he told me that story in the late 80's I've been running Redline CV joint grease in all of my wheel bearings.
