by Ron
(London, Ont, Canada)

Using an air impact gun to remove/install wheel lugs on passenger cars.

Want to purchase appropriate compressor and impact gun to change wheels on 2 or 3 vehicles twice a year (exchanging snow tires and regular tires).

Some impact guns produce approx. 275 psi torque while others are rated much higher (approx. 450 psi) but both appear able to remove/install lug nuts.

Those that I have looked at all appear to need just under 6 cfm at 90 psi which means I would need a 2 hp compressor.

1. Am I correct in assuming that a 2 HP with a 30 gal tank would be less costly to run than a 20 gal as it would cycle less often?
2. Are oil filled compressors better than oil-less?
3. How much torque is typically required to install/remove passenger car tires – using only the impact gun?
4. Will electric impact guns install/remove wheel lugs using only the gun?
I will have other applications such as inflating tires, etc. which will require less air that the impact gun.


If you are getting 6 CFM of flow from your compressor, and your impact wrench needs that flow, then theoretically, the air being generated by your compressor should power that impact wrench.

Impact wrench - this one made by Ingersoll Rand

Impact wrench – this one made by Ingersoll Rand

If you have xx amount of air in a tank that’s already pressurized in excess of that 90 PSI, then your gun will run for a few seconds before the compressor comes on, as the pressure in the tank drops.

I question the ability of your 2 HP compressor, running on 110 Volts, to generate the flow you need.

Re: #1) that depends on how much air you are using over what period. I’d default to the larger tank to be able to run my tools better.

#2) Depends. As I note on this website, with the developments in oil less compressors in the last few years, and the fact that their price is now commensurate with oil lubricated compressors, when I buy my next one it will be oil less.

#3) No idea.

#4) Possible. I don’t know. I’ve never seen an electric lug nut wrench in a tire shop. That should tell you something.

There is much more info on the Sizing your air compressor page on this site.

Be aware too that you can only get so much power out of a 110 Volt circuit, regardless of how big your air compressor is. Your compressor size is limited by the power supply.

Cheers Ron, and thank you for writing in.



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