If Your Spare Tire Sits On The Exterior Of Your Vehicle, Then It Is Open To The Elements And At Risk From Damage From Dirt, Debris, And Changes In Weather Conditions. Investing In A Spare Tire Cover Is The Best Way To Avoid Damage To Your Spare Tire And To Protect The Value Of Your Vehicle. Product Information Material: Polyester Size: 14 Inch, 15 Inch, 16 Inch, 17 Inch Package: 1 X Spare Tire Cover Cover Size Guide Tire Sizes Are Listed On Below Detailed Description, Please Measure Before Purchasing. Cover Size 14" Fits For Tire Diameter 60-69cm/23-27in Cover Size 15" Fits For Tire Diameter 70-75cm/27-29in Cover Size 16" Fits For Tire Diameter 76-79cm/29-31in Cover Size 17" Fits For Tire Diameter 80-83cm/31-33in Spare Tire Cover Diameter Calculation Guide Step 1: Find Your Tire Parameter. It¡¯s Written On Your Tire Side Step 2: Calculate Your Tire Diameter If 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 =72.43cm According To The Sizing Guide, 14" Spare Tire Cover Is The Size That Fits Your Spare Tire. Note Please Allow 1~2 Cm Deviation Because Of Hand-Cutting And Sewing.