Impact wrench buying guide: sockets, lug nuts and what to check

Cordless and air impact wrenches make quick work of lug nuts and large bolts. They also make it easy to break a socket or over-tighten a fastener if you use the wrong accessories or skip the torque wrench. This guide sticks to what published sources say, and each fact has a numbered source at the bottom of the page.

Use impact-rated sockets

Hagerty explains the difference between the two kinds of sockets.^[1] Standard sockets are made from chrome vanadium, which is smooth, hard, high-gloss and corrosion resistant. That hardness keeps them from deforming under high torque, but Hagerty says the same hardness makes them unfit for impact use.^[1]

Impact sockets are made from chrome molybdenum, also called chromoly, which Hagerty describes as tougher than chrome vanadium under hard impacts such as those from air or powerful battery-operated impact guns.^[1] An impact gun uses a spinning hammer and anvil inside the tool, which can give high shock loads.^[1]

If a kit includes sockets, check that the listing calls them impact sockets before you use them on an impact wrench.

Lug nuts: don't let the gun run until it stops

Chicago Pneumatic, a maker of impact tools, published an article on lug nut torque aimed at shops. Its main points:^[2]

• Vehicle manufacturers provide recommended torque specifications for each tightening job, and the specifications should be followed.
• It calls "the more you tighten, the better" false. In most cases more torque means more tension on the bolt, which raises the risk of the stud breaking.
• Over-tightened wheel nuts can become damaged or broken.
• A substantial amount of torque is lost to friction while tightening, so clean off rust, dust and dirt first, and inspect the wheel, studs and nuts.
• Signs of deformation or stretch on a stud suggest the tightening was above the manufacturer's specification, and the stud should be replaced.
• To avoid over-tightening on passenger vehicles it suggests a torque-limited impact wrench together with a torque wrench. It also lists a manual torque wrench as a way to prevent over-tightening.

The practical takeaway is to look up the torque spec for your vehicle in its manual and finish lug nuts with a torque wrench.

What to check on the listing

• Tool only or kit? Many cordless tools are sold "tool only," with the battery and charger sold separately. Our cards repeat that note whenever the listing says so.
• Drive size. Make sure the square drive on the tool matches the sockets you own or plan to buy.
• Power source. Cordless models run on a battery pack. Air models need an air compressor to run.
• Sockets included? If they are, see the section above on impact-rated sockets.

Sources

1. Hagerty, "What are impact sockets, and do you need them?". https://www.hagerty.com/media/maintenance-and-tech/what-are-impact-sockets-and-do-you-need-them/
2. Chicago Pneumatic, "What torque should lug nuts be tightened to?" (March 15, 2024). https://tools.cp.com/en-us/expert-corner/blog/fact-or-fiction-the-more-you-tighten-the-better

Last reviewed October 27, 2026. We update this guide when we find new information. See how we pick deals and the affiliate disclosure.