Originally Posted by
Metaluna
To be fair, the repackagers for the most part have at least done the legwork of figuring out for you which of the thousands of different formulations and grades available on the market are best for bike applications. So, while you can probably do as well or better for less money than the tube of stuff from the LBS, an unsophisticated user can certainly do a *lot worse* by choosing an inappropriate lubricant. And some of them do claim that their stuff is a custom formulation (doesn't mean they have to own a grease factory...I'm sure there are plenty of companies that will work with you for the right price).
True enough. Grease is formulated to give satisfactory lubrication at certain loads and temperatures. I'm sure that this is major issue with powered vehicles, especially aerospace stuff. I'm not a trained engineer, but I guessed that bike bearings are not under any more load than boat trailer bearings -- probably less. The marine grease I've been using has worked out just fine, at a fraction of the cost of boutique grease.