I’m not a good reference for your question. I have 35x12.5 R17 tires but I only go softroading rather than off-roading. I air down to about 25 PSI to get a smoother ride, not to get good floatation on sand nor to get grippy on rock crawling. I haven’t timed the minutes to get my tires back up to highway pressures but this Viair 400P is fast enough for me. If I was looking to go under 20 PSI for more serious wheeling then personally I’d consider a gas tank rather than compressor if speed was my prime concern.Do you air up your tires with that compressor? If so what size tire, what psi do you air down to, and about how long to air up all 4 tires? I see the fill rates on the website but I want to here your experience. What model is yours. Sorry for all the Q&A but I'm looking to get one. Considering ARB.