If you want to go fast, get a bike with gears, its that simple.
A single speed is a bike thats in the wrong gear 95% of the time and if its a fixed gear, you can't go fast around corners without a corner strike.
Besides, fixies are sooo 2008. Hipsters have long given up the fixie.
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Il faut de l'audace, encore de l'audace, toujours de l'audace
1980 3Rensho-- 1975 Raleigh Sprite 3spd
1990s Raleigh M20 MTB--2007 Windsor Hour (track)
1988 Ducati 750 F1