An Exercise in Word Replacement

The September 2006 issue of Physics Today included a reprinting of an old article about the stability of bicycles. This article includes the following sentence:

Besides, I did not want nasty variable frictional forces intruding into the pure, austere Newtonian bicycle theory towards which I was groping.


Hint 1: You only need to replace "bicycle," although I think it works slightly better if one replaces "Newtonian bicycle."

Hint 2: None of the new words are dirty.