The film "The World's Fastest Indian" is based on the real life Bonneville salt flat speed record attempts of a New Zealander called Bert Munro. (Anthony Hopkins plays the part.) Munro set his records on very low funding, making do with worn out equipment and home made parts. There's a scene in the movie where scrutineers find cracks in the worn-out tires of his Indian motorcycle on which he is intending to go over 200 mph. Munro filled the cracks with boot polish, the tires looked good and the scrutineers passed the bike!
Supposedly that bit is true.