Tire size for '57 Bubble

Have been reading up on all the various tire options out there. I think it's safe to say that a 225/75R15 D-rated tire is a common choice these days. What I don't know though is whether or not a tire that size will fit into the wheel well of a 16' Bubble. I know that smaller Bambis have limited wheel well capacity, but I don't know how true that is for Bubbles.



I read that some of the 16'-18' trailers originally used 6.70 x 15 sized tires, which more closely equates to a modern day 205/75R15, which is noticeably smaller than a 225/75R15. That makes me think that a 225/75 might have a problem fitting into the wheel well of the Bubble comfortably. Unfortunately, the 205/75R15 tires that I'm finding in stores locally are C-rated rather than D-rated...and I'm reading that C-rated tires should not be used for an Airstream. Additionally, I believe something as slight as a 205 requires a 5" wide rim, which doesn't have a weight rating of the recommended 2600lbs. I could step up to a 215, which would fit on a 6 inch rim, and are easily available in a d-rating, but if a 225 is a tight fit, not sure a 215 will be much better.



Does anyone know what the beefiest tire size is that will easily fit on a Bubble?



Thanks in advance!