Howdy all!
New in here as I just purchased a "new" used 2014 1500. The truck came with 30 x 12.5 R20 tires on it. There is no spare with the truck. I need to get a spare but don't want to spend all teh money on one of those tires just to sit on a rim (plus not sure it would fit up under the bed in the spare tire location. What tire would I get on a steel 20inch rim that would fit in the spare tire location and I could use it for a spare if necessary.

Cheers!

 

One stock tire size for a 2014 Ram 1500 was 275/60R-20, so from a diameter perspective, your 30 x 12.5 should fit in the spare tire recess. The 30 x 12.5 is actually a bit smaller in diameter than the 275/60R-20. According to this site, to get the same size in a metric tire size you'd need a fictional 318/40R-20 tire. Your best bet is likely to go with another 30-12.5 R20 as a spare, or carry a plug kit and portable air compressor with you and hope you never puncture the sidewall when in the middle of nowhere.

-Rod