09/06/2025
50 years of MICHELIN PLR
The MICHELIN PLR (Poids Lourd Rapide), one of the most extreme test vehicles ever built, turns 50 years old in 2025. Built in 1975, this 10-wheeled, twin-engine colossus wasn’t created for racing or military use—but rather to test tires. Half a century later, the PLR remains a wild and fascinating symbol of French engineering and Michelin’s relentless pursuit of tire durability and safety.
Here’s a detailed retrospective in honor of its 50th anniversary:
The MICHELIN PLR: A Colossus with a Purpose
Built in: 1975
Purpose: High-speed tire testing for heavy trucks
Manufacturer: Michelin, with support from Citroën
Base Vehicle: Citroën DS platform (barely recognizable)
Nickname: Mille-Pattes ("The Centipede")
Key Technical Features
Engines:
2x Chevrolet 5.7-liter V8 (small block), around 350 hp each
One engine powered the vehicle
The other exclusively powered the central test wheel
Drive Configuration:
Rear-wheel drive (vehicle movement)
Independent drive to central test wheel
Wheels:
10 wheels in total
4 pairs of standard car tires
1 central test wheel mounted in the middle, carrying the truck tire being tested
All wheels could be independently lifted or lowered to manage weight distribution
Chassis:
Custom ladder frame
Central wheel integrated into the middle of the frame
Citroën DS body shell heavily modified and widened
Weight: Over 9 tons (9,000 kg)
Top Speed: Around 180 km/h (112 mph) — remarkable for a vehicle of this size and weight
Dimensions:
Length: ~7 meters
Width: ~2.45 meters
Height: ~1.8 meters
Why It Was Built
In the 1970s, Michelin needed a way to test truck tires at high speeds under realistic road conditions. At the time, laboratory simulations weren't advanced enough to replicate heat buildup and wear. So the PLR was developed as a mobile test rig, allowing Michelin to test tires under real-world forces, loads, and high-speed situations.
The central test wheel could simulate loads of up to 5 tons, and the second engine ensured the tire was driven independently, at varying speeds and loads, allowing precise control and data collection.
Unique Aspects
Citroën Hydropneumatic Suspension: Used for superior ride control and load management
Custom-built dashboard: To monitor temperature, pressure, and wear on the test tire
Noise and heat: The driver cabin was insulated and air-conditioned — the rear engine created extreme heat
Still functional: The PLR is preserved and can still run today, thanks to Michelin's heritage department
Legacy: 50 Years Later
A symbol of Michelin’s engineering obsession and innovation
An inspiration for other tire-test vehicles
Widely featured at events like Retromobile, and at the L’Aventure Michelin museum in Clermont-Ferrand
Gained pop culture status thanks to its monstrous, otherworldly appearance
Summary
Fifty years after it first rumbled onto the road, the MICHELIN PLR remains a masterpiece of purposeful absurdity — a ten-wheeled brute that put performance above all else. Not built for speed records or fame, it’s become an icon because of its focused utility and bold design. As a tire-testing machine turned legend, the PLR embodies the kind of daring experimentation that defined a golden era of automotive innovation.
