Montlhery Vincent: 100mph For 6 Hours

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The Montlhéry race circuit, just 15.5 miles south of Paris, holds a place much like Brooklands in England in the hearts of European speed-fans, but the track isn’t a fractured memory from pre WW2, its a living thing in continuous usage since constructed in 1924.  Today the track is regularly pounded by automotive companies, being engineered to withstand 5,000lb racing cars traveling at 150mph – a far-sighted vision for 1920s engineers.  But then, French engineers of the early 20th Century were exactly that, out on the exploratory limbs of technology, making double overhead camshaft four-valve multi-cylinder motorcycles even in the ‘Teens.  What Montlhéry became best known for, though, was long-distance record-breaking; while nearby Arpajon was an excellent spot for Land Speed Record attempts in the 1920s and 30s, Montlhéry was a perfect venue to circulate for hours around its steeply banked oval, being relatively smooth (well, smoother than Brooklands…) and amenable to 24-hour full-bore, unsilenced riding.

On May 13 1952, a pair of mildly modified 1,000cc Vincent Black Shadows arrived in Paris to attempt a new 24-hour speed record, with a slew of Vincent factory employees (including 18 year old apprentice John Surtees), a few pressmen, plus a French team contingent of riders, the record-attempt team manager, and timing officials from the FIM.  One of the machines was a ‘test hack’ which circulated for hours during testing, on which modifications were made for an average/acceptable riding position for the 11 riders participating; Phil Heath, John Surtees, Robin Sherry (AMC factory racer), Cyril Julian (TT rider), Vic Willoughby (infamous writer for The Motor Cycle), Dennis Lashmar,  and Danny Thomas, plus four French riders; Ken Bills was team manager.  All the riders save Danny Thomas were able to keep up the 100mph pace, so he was relieved of duty.

After ten hours forty minutes, the standard big-end of the Vincent crankshaft failed, and a deafening silence rang in the speed bowl; the team ran to the far side of the track (a mile!), and waited 20 minutes to push the bike over the ‘line’ to take the 11hour record.  While a Vincent never took the 24hr/100mph record (it took a Velocette for that one), the Vincent team still took and impressive eight World Records, including the six-hour record at 100.53mph and 1,000km at 100.67mph, and 10 hours at 99.17mph.   Other records were 7 hrs @ 99.73mph, 8 hrs @ 99.73mph, 9 hrs @ 99.40mph, 10 hrs @ 99.17mph, 11 hours @ 91.98mph, and 1,000 miles @ 99.20mph.

2013-03-11 14:45:14

Source: http://thevintagent.blogspot.com/2013/03/montlhery-vincent-100mph-for-6-hours.html