Running tires on rims that are "too skinny"?

I need new tires in a bad way. Been running the 20" rims that came on my Tundra when I bought it. I picked up some 17x7 snowflake wheels quite some time ago because I want more sidewall. I found a killer deal on a set of 315/70r17 Toyo Open Country at3s. The "approved rim range" for them is 8.0-9.5-10.5. From people that really know this stuff, is the 7" rim a deal breaker? I've searched the webs and a ton of Jeep people don't seem to think it's a problem. Would appreciate hearing from my Tundra folk. Thanks for any input you can provide.

 

I'm not in the know, but if you mount those tires on 7" wheels your dropping 12.5% below the minimum approved wheel width. That's not a risk I'd be willing to take.
Get some pizza cutters that will fit your wheels, stay safe.

 

The short answer is "yes" you can do it. You are going to get understeer and they are going to be more difficult to balance and keep balanced.