An inverted tooth chain assembly configured to mesh with a sprocket is provided including a link with an improved shape for increased strength. The link includes two teeth, a pair of outer flanks, first and second inner flanks, and a crotch located between the first and second inner flanks. A first transition point is arranged between the first inner flank and a first end region of the crotch, and a second transition point is arranged between the second inner flank and a second end region of the crotch. A crotch surface is defined between the first transition point and the second transition point and has a profile with a varying radius of curvature. The profile of the crotch surface has a smaller radius of curvature at the first and second end regions and a larger radius of curvature at a medial region between the first and second end regions.