Originally Posted by
cxwrench
Post mechanical questions in the proper section...oddly enough it's called 'bicycle mechanics', not here in GD.
And I would never use soap of any kind on the drivetrain, you'll need a degreaser. Dawn works great on the rest of the bike.
A “degreaser” serves basically the same function as “soap” in that both allow for a nonpolar substance…oil, grease, etc…to be dissolved in a polar substance to a limited degree. Bar soap would probably not be the best choice because if its solid nature but body wash, Dawn dish “soap”, and Simple Green (as well as other “degreasers”) are very similar in nature and composition. The surfactants used in all of the liquid detergents are of a similar molecular structure.
That said, none of the water based surfactants are as efficient as using a nonpolar solvent for degreasing. Even with a very high load of detergent in water, there is only so much grease that any of them can dissolve meaning that gallons of water and detergent is needed to do the same work as a cup or so of mineral spirits, for example.