tires

[C-10volvo]

well today i went to the sears tire shop to get new tires and shocks. I got some monotube gas shocks, and a pair of Bridgestone dehuler a/t's for the rear (not real sure on the spelling) and they are 6 ply sidewalls. Anyways im running 235/75r/15's all around. and after i got them installed the truck felt like the read end was on ice. Changing lanes on the highway felt like my 1/2 ton truck had 2 tons of iron in the bed. i got off at the next exit and went back. i told the guy that these tires were unsafe and the sidewalls are way too soft. after another hour of him looking back at his computer and him showing me other options that were "better, but I wouldn’t know for sure till it was on the truck" b/s. so i just told him to put the old ones back on that ill get my money back. the tires that i originally had are toyo traction tires that he clamed were only used by police trucks. But anyways, after i got my old tires back on the truck was much better, and i once again felt safe driving that.
Since my truck has fairly basic options, it didn’t come with a factory sway bar. And i am ordering one soon from A-P-T. Has anyone else came across this problem? Does anyone have any tires that they would recommend? I need help fast, these tires in back aren’t looking to well.