Yokohama Rubber Co. Ltd. (TYO:5101) is making a push to grow sales for its lineup of studless winter tires. Efforts here are centered on the iceGuard 6 line, which launched around four years ago and is known internationally as the iceGuard iG60. However, there is also a focus on the iceGuard 5 Plus, a mass-market line; the iceGuard SUV G075,…