Originally Posted by
Bikesplendor
A meaningful difference, for some, is the longevity of the grease. Polyurea greases last substantially longer than most. They are recommended for applications in which service intervals are long or irregular. Most other greases age, degrade, harden, while the polyurea greases remain sound.
Lucas polyurea grease can be found in the auto section at WM, and elsewhere, in grease gun cartridges, for peanuts. It's often used on farm machinery, and is a favorite among farmers. Their requirements and conditions of use tend to be much more demanding than cyclists'. So I'm fine with that grease.
Water and, primarily, dirt intrusion is the nemesis of most bicycle bearings. So in those terms, a grease being long lasting doesn't make much of a difference past a year, or two (depending on riding conditions and mileage).
Based on my experience, general auto store lithium complex grease is more than good enough in terms of water washout resistance, durability (not drying out) and lubricating performance.
Another thing to consider with polyurea is that it's not very compatible with many other grease types. Which means that if one doesn't wipe off the old grease thoroughly (yes, one should, but I prefer having less things to go wrong if all else is practically equal), the two will mix and not work very well (becoming more "liquid", or less resistant to water washout, or something third - depending on the particular incompatible combination). That's another reason I prefer easy to source, relatively cheap lithium based greases (calcium based ones are similar, but as of last 20 years, I'd say lithium is a "no brainer" for general use - including bike bearings).
In a lot more detail:
https://bike.bikegremlin.com/1985/bi...ase-explained/