With the Giant Toughroad, you could look into 27.5 plus tires, like the 27.5x2.8 WTB Trailblazer, which was designed as a plus tire, working together with the 45mm rim WTB Scraper, to fit into existing 29er frames. The Toughroad is designed for 29x2.0, though, so there might not be sufficient clearance to either side of the tire.

On 30-35mm rims, a Trailblazer may be slightly narrower, allowing it to fit between the chainstays of a Toughroad. I mention a 35mm rim, when 40-45mm rims are commonly used with 27.5 plus tires, because other bikes like the Surly Ogre, that take 27.5 plus easily, often have clearance for 29x2.5 tires or more and thus have lateral clearance for fatter 27.5 plus tires.