Spare Tire Difficulties

My existing donut spare is not in very good shape. I tried to buy a new one, and discovered the exact replacement is apparently no longer manufactured. I'm trying to sort out what the closest size is that will fit on the rim and in the tire well, and finding little helpful information. I'm guessing that someone in Prius v world may already have figured this out. Thanks in advance for any wisdom anyone can offer.

 

Thanks for your reply. When I checked my Goodyear dealer, they said they didn't have access to the size. Checked using their tire selecting app, they didn't offer any tire close to the width size. Toyota dealer said they couldn't get them. I was aware that Honda had at least one model which used that tire size. I'll check with a Honda dealer. I had been checking at ebay, but hadnt seen any new . I'll check that out. Thanks again!

 

Update - I have found a supposedly pristine used one at Ebay. Keeping my fingers crossed.