In The Guardian Steven Poole reviews books that are down on Heidegger and notes about Max Horkheimer:

Oddly, Horkheimer also has a thing about motorbikes, despising folk who enjoy riding them but harbouring a deep erotic fascination himself: the "true pleasure in motorbike riding," he declares, "is in the anal sounds it emits." Interesting if true.

Someone ought to write a Horkheimer interpretation of Girl on a Motorcycle.  ¶ 2:37 PM