Why choose EWUTLNCA tire cover?-Durable, washable, corrosion-resistant, waterproof, dustproof, and sunscreen.-Effectively avoid spare tires such as tire wear, pollution, and degumming caused by long-term non-use.-A variety of colors and styles are available. Various sizes are available to suit most cars. Immediately improve the car's visual level, decorate the body, stylish and beautiful.-Adjustable nylon cord, tighten the adjustment cord to prevent the tire cover from falling off and protect the tire tightly.Cover Size GuideTire sizes are listed on below detailed description, please measure before purchasing.Cover Size 14" fits for tire diameter 60-69cm/23-27inCover Size 15" fits for tire diameter 70-75cm/27-29inCover Size 16" fits for tire diameter 76-79cm/29-31inCover Size 17" fits for tire diameter 80-83cm/31-33inSpare Tire Cover Diameter Calculation GuideStep 1: Find Your Tire Parameter. It's written on your tire sideStep 2: Calculate Your Tire DiameterIf your tire is written with P225/65R17, A=225 B=65 C=17.Tire diameter=A*B/500+C*2.54 =225*65/500+17*2.54 =72.43cmAccording To the Sizing Guide, 14" Spare Tire Cover is the size that fits your spare tire.