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Amazon.com : Challenge Grifo Cross Open Tubular Tire (Clincher) (Black/Brown, 33-mm) : Bike Tires : Sports & Outdoors
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Challenge Shows New Grifo Clincher and Gravel Grinder Tire at NAHBS 2014 - Cyclocross Magazine - Cyclocross and Gravel News, Races, Bikes, Media
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Challenge Unveils Grifo Race Clincher, Hints at New Gravel and Fat Bike Tires, Colors - Cyclocross Magazine - Cyclocross and Gravel News, Races, Bikes, Media
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