Originally Posted by Pete Hamer
Do you know what makes a grease a "high temperature" grease? Does it just resist liquification at high temps? Does it protect just as well at "low temps"?
High temperature automotive grade grease is a synthetic blend capable of withstanding very high temperatures generated by automotive disk brake hubs. It performs well in extremely low temperatures as well. Most all this type of grease is the same stuff approved for aircraft use, which needs to endure extremely low temperatures encountered at high altitudes. It costs less in that it does not go through testing for aircraft use, which would add considerable and unnecessary cost.
Originally Posted by Pete Hamer
What would make a grease "bicycle specific"? I'm guessing it's a combination of water resistance and viscosity but I'd love to know for sure.
You just package the grease in a tube labeled for use with bicycles. Typically, this grease will be the same as marine grade grease as most bearing on bicycles are not equipped with rubber seals that seal in the grease and seal out water, dirt, and grime. Most of them also contain Teflon in an effort to make it very slick and tacky and having Teflon listed on the package promotes purchasing that tube of grease on the shelf of your LBS.
You should service the bearings on your bike at least once a year. Not because the grease will be bad in a year but simply to remove any collected dust, moisture, dirt, metal shavings from the bearings and balls, and general grime.
ATB and MTB bikes used off road and do not have sealed cassette type bearings should have the bearing serviced every three months or after a ride where you got mud and water around the axels and bottom bracket.