BMW took back the Guinness World Record for longest drift. To do that, they needed to keep the car sideways and moving, with as few stops as possible. So they invented mid-skid refuelling to make sure the car can stay sideways long past the end of a normal tank of fuel.

To show off the rear-drive tail-happy new 2018 BMW M5, BMW wanted to take back a record they originated. The longest vehicle drift. BMW first set the record in 2013 by drifting a then-new M5 more than 82 km around their South Carolina test track.

But Toyota took that record away with the GT86, and currently holds it with a total drift length of 166 km in five-hours 46 minutes.

To get the record back, BMW needed to go to extreme measures. Since they're planning to drift for eight hours, they knew they'd need more fuel. But a bigger gas tank is too boring and a fuel stop too slow, so the team took some Air Force inspiration and developed mid-drift refuelling.

Instead of a boring rig that could link the cars, BMW put an extra tank in the back of a previous-gen M5. Then they added a long hose and a high-pressure pump and handed the whole rig to the guy in the back seat.

So the old M5 drifts up behind the new car and then a passenger reaches out and fills the tank, by hand, in about 50 seconds. While both cars are sideways.

Thanks to the rig, BMW took back the record. BMW driving instructor Johan Schwartz drifted for eight hours straight, completing a distance of 377 km. That's a whole lot of laps around the tiny circle.

But Schwartz made it. The full eight hours of non-stop drifting. Not even a bathroom break. It wasn't completely uneventful, in the five in-flight refuellings, the cars did have light contact. The result, though, was a success. 

The pair of M5s also set a record for longest twin vehicle drift, with a one hour, 81 km drift between refuellings.

We're still curious about how a set of tires could suffer through that punishment.