Automotive history is littered with great ideas that just didn’t pan out. Among them is an unusual-looking style of brakes pioneered by Audi, which had stopping power far ahead of their time. They did what they were supposed to, but like all attempts to reinvent the wheel, they also did a lot that they weren’t supposed to do, too. And that’s what brought them crashing down to earth.
These “UFO” brakes (as they’re now known) were conceived by Audi and brake manufacturer ATE for use on the predecessor to the A8, the 1988 Audi V8. This follow-up to the Audi 5000 was groundbreaking in many ways, from its 3.6-liter, all-aluminum twin-cam V8 to its variable all-wheel drive, which offset its weight to take two straight DTM titles in 1990 and 1991. The road there was a tricky one, as Audi found during the V8’s development that the sedan didn’t have enough stopping power, according to FCP Euro. Its 15-inch wheels didn’t have room for big disc brakes, and carbon brakes were still only workable on high-end race cars. To slow down the V8, Audi had to think outside the box—or rather, turn the box inside out, as it did with the V8’s “UFO” brakes.
This design began with extending the V8’s hubs further out than usual, to accommodate a unique style of disc brakes. Rather than fixing the rotor hat to the rotor’s face along its inner diameter, the hat was offset and enlarged to mate with the rotor along its outer edge. This let Audi move the brake caliper to the inside of the rotor, using the space freed up along the outside to expand the rotor itself to 12.2 inches. That’s bigger than the 11.1-inch rotors of the contemporary Porsche 911, according to Quattro World.
As a result, the Audi V8’s brakes had an unusually large friction surface and larger pad, improving heat exchange and greatly reducing brake fade. The wider rotor also apparently gave the brakes better leverage, reducing the pedal force necessary for stopping. Audi’s design worked exactly as intended, and the company was so proud of its work that it even used this style of brake on the original S4 in some markets.
Still, new ideas come with new problems, and the “UFO” brakes were no exception. Their unique design and exclusivity to just a few Audi models meant the brakes were expensive to produce, with Carbitrage reporting that rotors cost the equivalent of $550 per corner. For context, Audi dealers apparently charged $100 per corner for conventional rotors. Owners had to replace them more frequently too, as the UFO brakes developed a reputation for warping quickly in regular driving conditions due to uneven heating and cooling. From an outsider’s perspective, they also look unusually heavy and hard to work on, which would sacrifice some performance and complicate maintenance.
Possibly the strangest downside, though, was what people thought of how these brakes looked. They were highly visible behind the Audi V8’s standard alloy wheels, which in the late 1980s and early ’90s were a prestigious rarity. But, to some, they made the car look like it was on steelies with cheap wheel covers.
In the end, the UFO brakes went back to their homeworld, bidding farewell alongside the Audi V8 in 1994. The S4 and other users in Audi’s lineup switched back to conventional disc brakes, which began to get larger as big wheels became increasingly viable throughout the 1990s. Today, Audi V8s using their original style of brake are getting rarer, and not only due to the attrition that affects all old cars.
Between the rarity of parts, their cost, and inevitable shakes associated with UFO brakes, many owners have converted their sedans to conventional brakes, like Audi itself did. UFO brakes are now a rare sighting in their own right, and they’re absolutely worth snapping a photo of if you ever see them. Otherwise, people will just say you saw swamp gas or a weather balloon.
Got a tip or question for the author? You can reach them here: james@thedrive.com