How to know the correct size cover (S, M, L, XL, XXL) for your Tire?
You can calculate the correct cover size based on the tire specifications,

For example, your tire is written: P225/40 ZR18,
A is 225, B is 40, C is 18,
The Calculation Results (CR): (A × B) / 1270 + C, it's (225 × 40) / 1270 + 18, the result is 25.09,
So that an "S" size cover fits for your tire.

S: for CR 25~27.3,
M: for CR 27.4~29.3,
L: for CR 29.4~31.3,
XL: for CR 31.4~33.3,
XXL: for CR 33.4~35.0,

S size fit for:
195/55R16, 205/55R15, 205/55R16, 205/60R16,
205/65R15, 205/65R16, 205/70R15, 205/70R16,
205/75R14, 205/75R15, 215/50R15, 215/60R15,
215/60R16, 215/65R16, 215/70R15, 225/55R17,
225/65R15, 235/60R16,

M size fit for:
205/70R16, 215/70R16, 215/75R15, 215/75R16,
225/60R18, 225/65R17, 225/70R16, 225/75R15,
225/75R15, 235/55R18, 235/60R17, 235/65R16,
235/65R17, 235/70R15, 235/75R15, 245/70R15,
255/55R17, 255/70R15,

L size fit for:
215/85R16, 235/65R17, 235/70R16, 235/70R17,
235/75R16, 235/80R16, 235/75R15, 245/55R19,
245/60R18, 245/70R16, 245/75R15, 245/75R16,
255/70R16, 255/70R17, 255/75R15, 255/75R16,
265/50R20, 265/65R17, 265/70R15, 265/70R16,
265/75R15, 275/40R22, 275/45R21, 275/65R17,
275/70R15, 285/60R17, 30x9.5-15, 31x10.5-15,

XL size fit for:
235/85R16, 245/70R18, 245/75R17, 255/70R18,
255/75R17, 265/70R17, 265/70R18, 265/75R16,
275/55R20, 275/65R17, 275/65R18, 275/70R17,
285/60R18, 285/70R17, 285/75R16, 275/75R17,
305/65R17, 33x12.50R15LT,

XXL size fit for:
315/70R17, 33x12.50R16.5LT, 285/75R17, 265/75R18.

If your tire specifications are not listed, you can Calculate the correct tire cover size or write to us.