Hum---you know, the black squiggly is alot more pronounced than the 'gear'. If it were a brake hose, it wouldnt be as 'bold' looking. Ever seen a hose from that era after submersion? I have---They definately do not look real black. More of a mat black. In most cases, the black coloring will come off in your hands, making it a more mat finish---if it even stays together. Same thing happens to the hydraulic hoses on boats around here---exposed to salt water, the cover color will literally rub off on your hands. Now in 1937, the hoses were not the same construction as we have now.
If you look at the pic, and invision the tire, comparitively it should be as bold as the 'hose' if it is a hose. This squiggily thing is dark, and there are no other organic things there to compare the color to----
tom