Michelin Built This Freakish 10-Wheeled Citroen to Test Truck Tires at 110 MPH

This is the Trojan Horse of the car world.

byRob Stumpf| PUBLISHED Nov 3, 2020 1:00 PM
Michelin Built This Freakish 10-Wheeled Citroen to Test Truck Tires at 110 MPH

Ten tons, 700 horsepower, and 11 tires actually touching the ground. The Citroen PLR is one of the most unique vehicles the world's ever seen, and it's also been called many names throughout the years. Whether you know it as the Mille Pattes, the Citroen Centipede, or the Michelin test car, the absolute absurdity of this French masterpiece remains the same.

The official name for this custom Citroen is Poids Lourd Rapide, which roughly translates into "fast truck" in English. It was built by a team of Michelin engineers in 1972 as a testbed for the company's commercial vehicle tires, and while you might think that having 10 visible wheels means that the vehicle would be able to test a number of tires at once, you've fallen for Michelin's Trojan Horse. Inside is a contraption used to test even larger tires, and the surrounding shell is merely nothing more than a safeguard for the driver.

The PLR is an odd specimen. Michelin chose the Citroen DS platform (front-engine, front-wheel-drive) as its starting point given the company's on-and-off relationship as the majority stakeholder in the French automaker. It further crafted bodywork from the DS Safari into the project's heavy customization and ended up with a wheelbase nearly 23 feet long.

About the wheels. There are 11 of them total, 10 of which were sourced from another commercial application, the Citroen H van, and are used for core vehicle operation. The front four are for steering and the rear six are drive wheels, and all in all the contraption tipped the scales at 21,000 pounds, which is roughly the weight of six brand new Toyota Camrys.

To move all that weight, the PLR needed some power. At the rear of the vehicle, you can peer into one of its three hatch-mounted rear windows to see not one, but two GM-sourced 5.7-liter small-block V8s sourced from the mid-tier C3 Chevy Corvette. Each engine reportedly produced about 350 horsepower, so about 700 ponies total.

Five vertically stacked radiators were used to cool the engines and the PLR's bodywork was sculpted specifically to direct airflow to the coolers, as shown on this Facebook post.

via Facebook

Now here's where things get even trickier. Only one of the engines sent its power to the three Peugeot 504-sourced drive axles, while the other powered a secret 11th wheel tucked deep within the PLR.

This 11th wheel was the PLR's secret sauce: the reason for its existence. The idea was that Michelin could place a large commercial tire in the center of the 10.5-ton PLR and bring it up to speed without worrying about a blowout causing the vehicle to lose control—that's where its 10 other wheels came in handy. The tire was surrounded by a large fender to prevent shredded rubber from flying around inside the vehicle and was placed directly behind the front row of seats, as shown in this photo.

via Facebook | Micha Socke

The heavy hunk of metal could reach a top speed of 111 miles per hour—nearly as fast as the Corvette its power was garnered from. Between the power, weight, and simple inefficiencies of disco-era automobile engineering, the setup proved to be quite fuel-hungry, so engineers installed dual 23-gallon fuel tanks to support the car's thirst. It's not clear how much range that gave the PLR, but we're guessing the answer is far from praiseworthy.

As technology improved over the years, the PLR became obsolete. Gone are the days where this multi-wheeled monster would spend its days testing at Michelin's Test Track Ladoux in Clermont-Ferrand, France. Tire manufacturers began moving their testing inside of their factories using advanced machinery and treadmill-like devices to measure wear and load.

Michelin didn't say just how long the PLR stayed in service, nor how much it cost to the manufacturer, but it is an important piece of company history nonetheless. Rumor has it that Michelin sometimes puts the vehicle on display at L'Aventure Michelin, the company's dedicated museum in France.

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