x2 on BC's explanation. I thought a 100-PSI rating would adequately inflate 80-PSI rated tires. NOT enough margin. A compressor bought for Class C should have higher than 100. Difference with BC's compressor and mine is that mine won't last through a lot of running. And airing up an RV tire is a lot IF it's similar to what happened to me. Tire shop inflated my spare to 60. That's what I specified for front tires. And by the way, RV was borderline uncontrollable with 80-PSI in Front! Back to the spare. I keep it under the bed so I carried the little HF compressor inside and it took probably 10-mins to get to 80. Next time I used the compressor, about all it would produce was 30-PSI.
That Porter-Cable, 150-PSI and 5- or 6-GAL is much better. My SIL has one of those from Home Depot and it's good. I don't know if HF's with similar specs at a lower price, would perform as well. And more importantly, would it last as long...