It needs regular emergency repair en route, and when it’s not being mended, we’re getting questioned at (all-too-frequent) checkpoints by the Mauritanian military.
They want to know just why two nutcase Westerners are slumming it through their country.
Fortunately our fellow passengers and three-strong crew are friendly, and relaxed, enough to take this all in their stride.
In fact we're enjoying some preferential treatment on this magical mystery tour, up front as the bus slews and bobbles and a crewman dextrously knocks up brews on the hour.
When a tyre bursts in the middle of nowhere the driver - hardly a stranger to this sort of thing - barely bats an eyelid.
When eventually we take off again, one passenger gets left behind, his frantic wife screaming 'go back'.
Again the driver barely bats an eyelid.
There will be another bus, he tells her... in 36 hours. We're beginning to learn that this is how it rolls in Africa.
Very, very, glad it wasn’t us...