Is there anything special about my greases gun(s)? No. I've got two of them pictured to the right of my little pump-action oil can. I'm actually more interested in making sure you HAVE a grease gun, or some mechanism by which you grease things. Also, I'd like to share a little thingy I ran across on rec.bicycles.tech years ago about grease in general. It's the best analysis I've seen. It's the only analysis I've seen. Which makes it the best. It's from Nick Gnesda, who was not a grease expert, just a person who decided to lubricate his brain with a little research:
Sez Nick: I wondered about the "best" grease for my road bikes when I noticed that I could not get any performance data on the grease offered at most bicycle shops in my area. My problem, how could I tell if the grease I was using was any better than (or anything different from) lard & olive oil? Furthermore it seemed that any recommendations I could find on the web were nothing more than good intentioned opinions.
Based on this I decided to do a little digging. Here's what I found.
The American Society for Testing and Materials (ASTM) has defined a number of performance tests for grease. It turns out that automotive greases that carry the NLGI GC & LB rating (typically automotive grease has this rating in the USA) on the package must execute a particular suite of standardized tests AND meet a set of performance minimums. I noted that I did not find any greases sold at my local bike shop that advertised any lubrication/wear based performance standards. Simply said, there are many tests. I don't claim to understand these tests to any great degree - but I believe given some test results it's pretty simple to determine which is better. Here's a couple of the tests (I hope the lubrication gods forgive my simplistic descriptions).
- Rust Protection (ASTM D-1743): pass or fail - bearing, grease, and a corrosive agent are combined for a while. Look at the results ... to much corrosion and you fail.
- Wear Protection (ASTM D2266): This is called the Four Ball Wear Test. Basically you stick four ball bearings in special test machine, add lubricant, then set the internals of the contraption spinning changing speed, time, and pressure per test standards. When your done the bearings are examined under a microscope. The tests are complicated - as are the other tests listed below - but for simplicity's sake is enough to say that this particular test measures the wear scar left on the bearings - lower is better.
- EP Performance Load Ware Index (ASTM D-2596): Weld Point - Basically this test increases the pressure until the bearings weld together - higher value is better.
- Water Washout (ASTM D-1264): less is better.
- Timken 0K Load test - increase the load until seizure or scoring takes place. higher is better.
I looked at a number of different greases and decided to pick from greases that came from companies that provide performance data on the web. The best I've found to date is STA-PLEX™ extreme pressure red grease. It's about $4 for 14 ounces (more than I'll use in a very long time). Some of the performance number are right on the package - I believe the Timken test is 80 lb. - an excellent reading. STA-PLEX actually beat KRYTOX GPL #225 grease in the Timken 0K load test (KRYTOX scored 50 lb). I sent some email to the STA-PLEX technical folks and received the following information:
STA-PLEX Extreme Pressure Red Grease;
- Rust Protection(ASTM D-1743)
- Distilled Water- No 1 - Pass
- Sea Synthetic Water - No 1- Pass
- Oil Separation (Bleed), % (ASTM D-1742) = 0.7
- Wear Protection (ASTM D-2266), Scar Diameter 0.38 mm
- EP Performance Load Wear Index (ASTM D-2596) 88 Kg , Weld Point - 880 Kg
- Water Resistance (ASTM D-1264) % Loss = 1.7
- Maintains 80 lb. Timken OK Load
- Typical drop point: 500ºF
All in all some very good numbers - and it's less expensive than the typical bike-store grease. At this point I can't say for certain if this grease will be better than the stuff my local bike shop recommends. But at least I now have some real information and I can make an informed choice - I expect this stuff will work quite well.
A world about TEFLON™. This is Dupont's trade name for a chemical called forpolytetrafluoroethylene (PTFE) - it's basically a resin that can be applied to a surface or molded into a number of shapes. The most popular TEFLON application is providing that non-stick layer on cookware. The really good stuff - when it comes to lubrication, is Dupont's PerFluoroPolyEther (PFPE) based products. PFPE looks (chemically) a lot like PTFE (TEFLON) but it is much better suited for lubrication. Something about the size and structure of the molecule makes PFPE much better at lubrication. I don't know the details but I do know that PFPE is what Dupont puts in its KRYTOX™ line of lubricants. KRYTOX has an excellent grease GPL #225 but it costs more than $90 per 16 ounces here in the USA - if you can find it.
