There weren't any rumors of doping or other cheating. Nor were any questionable decisions by race officials.
The fact that he was 37 years old--ancient for a European pro cyclist--or that he'd been trying to win that particular race for years didn't get tongues wagging. Even his palmares, which included a number of wins and high places in one-day races but no such results in multi-day events, wasn't the reason why cycling fans and the media were shocked when he won the Paris-Roubaix.
When Gilbert Duclos-Lassalle ascended the podium in the Roubaix Velodrome on 12 April 1992, no one talked about the course of the annual race--dubbed "L'enfer du nord" (the Hell of the North) for its cobblestones, mud and unpredictable weather-- or his persévérance. Rather, all of the attention was on his bike--specifically, one part.
At that time, suspension or "telescoping" (as they're called in Britain) front forks were the hot new item on mountain bikes. Until that day, no one had seen them on road bikes.
Gibus, as he was called, rode a LeMond road bike equipped with a specially-modified Rock Shox fork. The funny thing is that, with all due respect to LeMond bikes, the fork was really its only unusual feature. The rest of the frame was a typical road bike of the time, equipped with standard Campagnolo road components.
What's surprising, to me, is that there weren't more attempts to create suspended road bikes before Gibus rode his. The great Bernard Hinault won the Tour de France five times and a number of one-day events. But he refused to ride Paris-Roubaix until 1981 (he won) because the jarring conditions would aggravate his tendinitis, the condition that caused him to withdraw from the cold, rainy 1980 Tour. He's not the only elite cyclist who couldn't or wouldn't ride P-R because of bone-shaking conditions.
Since then, road bikes have incorporated various forms of front suspension. Rear suspension, however, caught on in any major way with professionals because it's difficult to achieve a balance between weight, shock absorption when needed and stiffness when ridden on smooth surfaces.
In April 2018, Specialized applied for a patent describing a system that allows the upper portion of a bike's seat post to move and absorb shock. To accomplish this, the seat post is clamped much further down the seat tube. The patent application, approved in October of last year, indicates that a pivot could be placed there and that it might be adjustable to the rider's weight.
According Specialized, the system could make its appearance on, appropriately enough, the company's Roubaix model. And it might come out next year: the 30th anniversary of Gilbert Duclos-Lassalle's first Paris-Roubaix win. (He also won the following year.)
I can't say I'm shocked.
Photo of Gilbert Duclos-Lassalle in 1992 Paris-Roubaix by Graham Watson. Drawings from Specialized patent application.