2018 Plus trim level. 195/65R15 tires. Getting a spare wheel & tire. What offset is OEM for 15x6.5

Toyota Prius Prime 2018 - Wheel & Tire Sizes, PCD, Offset and Rims specs - Wheel-Size.com

40 mm positive offset. 5x100 bolt circle. M12x1.5 bolt thread. 54.1 mm center bore.

A compact spare wheel from an older Prius or Corolla from a junk yard or fleaBay, new compact spare tire, and you're set to go. Be sure to lash the spare down securely. If someone hits you, you don't want the spare to become an unguided missile inside the car.

 

If you want a full size spare, either pick up another stock wheel, or this black steel Corolla rim will work too:

Corolla steel rim, part no: 42611-02471 (2003-2008 corolla or matrix, CE, LS, S)

For temp spare rim, I would go with the third gen sizes. Fourth gen rim/tire combo works out to roughly the same, but somewhat undersized outside diameter.

 

Hmm - NY? Get a set of snows on OEM wheels and you'll have four spares...

 

Just soap boxing: if nobody buys the levels (or models if it comes to that) that don't have spares, this situation will change.

 

The bottom photo shows where you can see the specs of the stock wheels. offset is 40 mm

 

Tire Rack:

https://www.tirerack.com/wheels/results.jsp?&autoMake=Toyota&autoModel=Prius+Prime&autoYear=2020&autoModClar=Limited