Buy 2014-2019 Acura MDX Spare Tire Hoist Dorman for a low price of $82.43 at PartsGeek. FLAT RATE SHIPPING on most Dorman 925-502 orders.
is the full size wheel will fit in spare tire compartment underneath the 2015 MDX?The stock tire size is 245/60-18. The outer diameter of the 165/80-17 stock spare tire is 7.4 percent smaller than stock (27.4" vs 29.6"). The 165/90-17 is 3.0 percent smaller than stock (28.7"). It should work fine on the car, with no problems.
A full-size wheel and tire is another alternative, and won't have limits on your speed or miles like a compact spare tire does. You can find full-size used stock wheels on car-part.com; it may come with a tire, but if it doesn't, you can find used tires here and here.