How long can uncooked beef rib grilling steaks last in the freezer?

Freeze them while raw. They can last six to nine months well, if properly wrapped for the freezer.

When ready to prepare them, defrost in the refrigerator for twenty four hours before you grill them.

@zenvelo Can I use the Styrofoam container that I buy it in? Should I remove the pad?

Wrap the whole thing in plastic wrap, including the styrofoam and the pad, if the steaks are packaged separately. If you buy them Ina multipack, like four or five together, then wrap the separately with none of the other stuff. Make sure you use plastic wrap that says it is for freezing.

You should take them out of the styrofoam package and wrap each individually in aluminum foil as tightly as possible. Label with the date and yes, six to nine months is about right.

Wrap them tight so no air is between the meat and the container for long term freezing and you’re good up to six months. If by styrofoam you mean the typical styrofoam bottom and plastic all around, I think that’s fine for a month or two of freezing. If you mean a styrofoam box that doesn’t close air tight, that isn’t sufficient for freezing.

Consider a Handheld Vacuum Sealing System. Reynolds made one a few years back called the Handi-Vac. It’s no longer available, but you can buy them on the secondary market (thrift store) for a buck or two, and they should work nicely with the bags made to work with the system currently available at Walmart.
Or if you’re really handy…