After experiencing my first tire blow out which caused $4500 in damage to my truck, I was in a fairly emotional state and willing to spend some money. During the process of changing to my under inflated spare, I discovered my current tire inflator was inadequate. I went shopping for a better one and decided on the VIAIR 400P Automatic. Automatic meaning it has a pressure switch and shuts itself off after the air hose is pressurized.
The unit comes with a coiled air hose, a nice tire inflator with gauge and a good quality storage bag. The storage bag has separate compartments for the compressor and air hose and holds everything nicely. It also has ample room if you wanted to put a tire plug kit or such in there. The unit is equipped with standard quick connect air fittings. This would make using different accessories/hoses quite easy.
Unfortunately in my case I wasn't able to use the supplied storage bag. It's kind of big and I want to keep the unit in my truck even when not hauling the camper. I found that it fits nicely under the back seat storage cubby....
The only assembly required is to attach the supplied air filter. The filter has 2 elements inside and even comes with extra elements if they should become too dirty....
Now, onto a performance test. The unit hooks directly to the vehicle battery with good quality clamps. The instructions say to have the engine running during use, which I did. I deflated one of my truck tires to 0 psi and re inflated it to 75 psi. The valve stem was pretty close to my wheel cover but I still had no trouble attaching the supplied inflator/air chuck. I also carry a 4" valve extender just in case. It was not needed for this test.....
When I turned the unit on it took 6 1/2 seconds to "charge the hose" before turning off. I then attached the air chuck to the valve stem and began inflating. I stopped in 1 minute increments to record the current pressure....
1 minute, 19 psi
2 minute, 31 psi
3 minute, 42 psi
4 minute, 53 psi
5 minute, 63 psi
6 minute, 72 psi
6 minutes and 15 seconds to 75 psi...
This unit doesn't have a 100% duty cycle so stopping every couple of minutes is probably a good idea. I did notice that the supplied inflator gauge is about 2 psi off from my usual gauge. Took about another 30 seconds to reattach and correct to proper pressure.
Overall this compressor has a solid well built feel to it. It is a bit on the large side compared to some others. The only negative I found was the supplied coiled air hose. It reached the rear tires on my truck just fine but I think if I had tried to stretch it to trailer tires it would have been, well, a stretch. It feels tight when you try to stretch it and I'm afraid if I would have pulled it much further than I did it would have kinked. If you find this hose to be a bit short you could add a 2nd hose or switch to a different hose such as a 50' non coiled hose.
All things considered I am very happy with this compressor. There are less expensive options available in the VIAIR product line and others. This one was a bit on the pricey side but I feel it is worth every penny. Hope somebody finds this useful.....
Erick