My 275/55-20 tires measure out to 31.9". Today I managed to fit (uninflated) a full size spare. I have a small air compressor so I could inflate the tire when needed. Did not have to force the tire either. To be able to install the tire/wheel I had to trim the excess material from the back of the receiver (flush with the main bracket WITHOUT removing any of the welds). Also the extra threaded area of the bolts (just 2 needed trim). The TPMS light did not come on either, so that may lead me to believe that the system reads 4 sensors, not all 5. I will be traveling to Michigan next week and now have peace of mind with a full size spare. If anyone wants pics, let me know and I will post.