In this paper, we study the approximability properties of symmetric TSP under an approximation measure called the differential ratio. More precisely, we improve up to 3/4 - $\epsilon$ (for any $\epsilon$ > 0) the best differential ratio of 2/3 known so far, given in Hassin and Khuller, “z-Approximations”, J. of Algorithms, 41(2), 429-442, 2001.