Originally Posted by
TimothyH
I should have said silicone based instead of synthetic. Obviously the Mobile 1 product is not silicone based. That was my mistake.
Those are two very different materials.
Originally Posted by
TimothyH
It is generally accepted that petroleum based lubricant run the risk of deteriorating rubber and plastic o-rings, seals, etc. We can argue about what constitutes a petroleum based lubricant or discuss the definition of rubber but the safest thing to do is to avoid petroleum based products if there is any doubt about contact with plastic or rubber.
It may be "generally accepted" by people who don't know anything about materials, especially elastomers (aka "rubbers"). But it is also very untrue and not accepted by people who actually know something about materials.
Some elastomers shouldn't be used with
some petroleum products but a blanket statement that
all elastomers shouldn't be used with
all petroleum products is overly broad and shows a lack of knowledge about chemistry. If you expand the statement to all
plastics...of which elastomers are a subset...the statement is even more incorrect.
Generally speaking, plastics...including elastomers...on bicycles are resistant to any degradation caused the classes of petroleum products used common bicycle lubricants. Shimano, for example, has been using a "rubber" seal on their hubs for 25 years or more. I have yet to see one that has deteriorated because of the grease in the hub.
Given the title and intent of this thread, I would even go further and suggest that some of the "alternative lubricants" being suggested could have unintended effects on the very "rubbers" and plastics you are trying to protect. Buna rubber, for example works quite well in the presence of the petroleum based products used in bicycle lubricants. It doesn't fare so well in plant based oils like citric oils, olive oil, corn oil, etc., however. It's difficult to predict how a material will perform in the presence of different materials.
Originally Posted by
TimothyH
I err on the side of caution. People are free to use what they want, or to just laugh at me as is the case with your response. It wasn't the first and won't be the last. I really don't care.
Sorry, I shouldn't have used that emoji. I apologize for that.
I err on the side of knowledge which is better than erring on the side of caution. My work requires that I know about material compatibility all the time. I've been bitten by materials incompatibility too often to do otherwise. Bicycle maintenance doesn't require that level of scrutiny...unless you go off the rails and start using weird combinations of materials in some misguided effort to "stick it to the man, man!". The nice thing about those "expensive" bicycle products is that they have generally been tested for compatibility with bicycle parts. Other chemicals may surprise you in very unwelcome ways.
Originally Posted by
TimothyH
For those who have an interest in the topic apart from mocking however, Napa Sil-Glyde is a good, general purpose silicone grease and dirt cheap.
While it may be a good grease, it's no better or cheaper than Park Tool Polylube or Phil Wood "green" grease. But even those aren't any better or cheaper than just about any other grease used for automotive bearing applications, although, in my experience, the automotive greases are thicker. Bicycle specific greases tend to be a bit lighter and easier to turn.
None of them are going to harm anything on a bicycle, however.