How to Determine the Right Spare Tire Cover for my LT235/80R17 Size Tires

Updated 01/30/2015 | Published 01/29/2015

Question:

By my calculations this cover should fit my tire. It is a LT235/80R17. Do you agree? I went ahead and placed the order tonight online.

asked by: Mike B

Expert Reply:

Yes I agree. The Rampage spare tire cover # RA773215 will fit your LT235/80R17 because your overall diameter is between 30-32 inches. Your diameter is 17 which is the diameter in inches of the wheel on which the tire is mounted.

Or you can do the math if you like. On your 235/80-17 tire size, take the first number 235 and convert to inches (235 x 0.0394 = 9.26). Then multiply 9.26 by 0.80 which is the sidewall aspect ratio (9.26 x 0.80 = 7.40). Next, multiply by 2 (7.40 x 2 = 14.8) which determines the amount of tire extending out on both sides of the wheel. And last, add your wheel diameter, in inches, of the wheel on which the tire is mounted, in this case 17 (14.8 + 17 = 30.9). That 31.8 is the tire diameter/height, give or take a fraction of an inch.

I included a helpful article for you to look at too.

expert reply by: Chris B