I found the tires specs on the Bridgestone-usa site but no inflation table for it. Strange that a company that makes a lot of noise about tire safety (since the Explorer-Firestone debacle) makes it hard to find inflation data. I guess you will have to go to a Bbridgetsone dealer and ask - they are supposed to have them for each tire model. Before you do, you need to know the weight carried by each tire, preferably by weighing each wheel separately. But both tires on the same axle must be inflated to the same pressure, so it's good enough to weigh each axle, divide by 2 and round up to the nearest 100 lbs.
Tite inflation is by weight range. The 85 psi maximum shown on the sidewall will also give a weight with it, i.e. xxxx lbs at 85 psi. A tire pressure of 85 psi will support that much weight. Less weight allows less pressure, but you never want to be under on pressure. Excess pressure gives a hard ride and may cause the center of the tire to wear faster than the edges, but will avoid premature tre failure.
If your weights are near the maximum weight rating, go with the 85 psi max pressure. I would estimate that "near" means within 250 lbs on this tire. If more than 250 lbs under the max weight rating, you could probably go with 10 psi less. I wouldn't go much lower than that without seeing an actual tire inflation table from Bridgestone, which will give exact inflations for each weight range. 65 psi is probably a minimum for the tire, but that sheer gueswork on my part. As I said, you never want to be low on pressure.