Although the 235/65-17 will retain close to the factory diameter, the 235 tread width may be too wide to fit your tire cover over. I have a 225/75-15 inside mount spare and the tire cover just fits over the tire. I have 235/75-15 mounted on the vehicle and the tire cover will not fit over the tires. You would be able to mount the wider tire inside the vehicle (as the overall diameter is the same), you just may not be able to use the cover as the tread is wider. If the tire cover is important to you, try fitting the cover over the tire before you buy.