I used to be a "grease is grease" guy.
Then, I tried Valvoline Synthetic in the wheelbearings of my VW racecar - tapered roller bearings, preload til the washer moves with "slight" force, done.
That always resulted in a LITTLE play at the wheel - wheel off the ground, grab at 10 & 2, slight clunk. "Normal," my mechanic friends told me. OK. If I _did_ tighten to the point of zero play, there was considerable drag.
Then, I tried Valvoline Synthetic. All of a sudden, I could run the bearings tight - *zero* perceptible play (IE, no camber changes under load), AND the wheel spun more freely.
Sold.
V-synthetic also works in CV joints - many greases don't, and the "correct" grease for German CV joints is expen$ive. I like Valvoline Synthetic.
I've had similar results with Mobil 1 Synthetic grease.
OK, so I was sold on "synthetic" grease for a long time, bought Valvoline or Mobil1, depending on price and availability. It only REALLY mattered to me in wheel bearings, but whatever, both come in tubes, easy to get, etc.
Last winter, I needed a new tube for the snowmobiles. Was at the autoparts store, and I saw a tube of some sort of grease - white tube, black and red lettering on it. Pictures of ag-stuff, machinery, claims of water this and temperature that, shrug, sounds good - snowmobiles see lots of water and temperature.
It was red, sticky, shrug, seemed ok.
Then, one day, a cold day, we were out skiing. The people riding my second sled - the spare, The Lifeboat, whatever, complained that it was hard to steer.
"Whatever" I told them. "Give it a little throttle, the skis will get light."
No, Iain, it is HARD to steer.
They convinced me to jump on it. Did. OH MY. Like something is wrong. Hood open, on it's side, wow. REALLY hard to turn. They were NOT kidding. Could not find anything obviously wrong.
Got it home, started disconnecting stuff - bent rod dragging on something? Disconnected the tie rod ends, handlebars and linkage are smooth (and floppy and worn out, hey, it is an old sled....). Skis, however, WOULD NOT TURN.
The ski spindle goes through the trailing arm - steel spindle, two plastic bushings, top and bottom, zerk fitting on the steel tube.
Long story short, the spindles had seized in the trailing arm. With a floor jack on the bellypan of the sled, I could easily grab a ski loop and pull the sled off the jack. Normally, even WITH the tie rods connected, I could "high five" a ski loop and the skis would just flop that direction. Hammered them out, cleaned, sanded, etc, regreased with V-syn (or M1, forget), problem solved.
So.....yeah. For the sled, I did not really care - temperature was the critical one, I grease the sleds a LOT. The marketing on the tube of this stuff made it sound like it'd be a better choice for LOW temps.
Wrong. Marketing got me.
Now, granted, there's 10 years and 4500 miles of who knows what built up in there, and maybe ANY grease would have done it, but I'd ridden that sled on colder days before switching to the red crap.
+another one for Valvoline or Mobil1 synthetic.......
Iain