It boils down to three things.
The Bugatti Chiron Super Sport 300+ is not your average road car. The specially-modified Chiron is now the fastest production road car on the planet, having taken the title from the Koenigsegg Agera RS. The so-called "standard" Chiron would not have been able to hit that 304.77 mph top speed without some necessary modifications, most noticeably the long tail body style. We spoke to Bugatti board member for R&D Stefan Ellrott at the 2019 Frankfurt Motor Show, who revealed that the key areas of extensive modifications were aerodynamics, downforce, and tires.
First off, why the long tail? "Because of aerodynamics. At that kind of speed, aerodynamics is one of the most important details on the car. To reach that kind of speed on the Chiron you have to reduce drag and to reduce drag you have to minimize the surface in the back." There's also a certain safety factor as well: keeping the vehicle planted to the surface. That's where downforce becomes vital.
"You have to make sure the end stays on the ground. It's a little bit difficult because the downforce balance has to be very precise. You don't want to have too much downforce because the car is too nervous and unstable at that kind of speed. You have to make sure the balance is good. This can only be simulated at 236 mph (380 kmh) in simulations. But the truth is on the road. We also used Porsche's wind tunnel for testing."
Bugatti didn't just make these modifications and hope for the best, but instead was 100 percent confident it could get the record. "Yes, without that confidence we wouldn't do any kind of testing with the car. It took us one week [at the track] to get the car running and set the record."
The Chiron Super Sport 300+ also wore unique Michelin Pilot Cup 2 tires. Driver Andy Wallace further explained to us that these tires feature "thin metal strands going radially around the edge and are equidistant of each other. The compound of the tires is exactly the same as any Chiron tires. Only the steel belts were reinforced. At the end, the tires looked brand new and pressure remained stable." That's pretty incredible considering these tires "had to withstand 5,300 g while rotating 68 times per second."
Now that the Chiron has set the world speed record, what's next, aside from two new Chiron variants? Electrification, perhaps? "Let me describe it like this: If I look far down the road at the end of the road I can see an electrified car. But it's far, far down the road. Right now we are celebrating the W16 engine with our customers. It's a piece of art. If I look far down the road for a hyper sports car, it's still several years away. But it's not something we're ruling out because it's where things are going. It is being discussed."