Cordless impact wrenches vs. air tools

Are pro grade cordless impact wrenches strong enough to remove stubborn lug nuts, or must I stick to compressed air tools for the job?

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Q: Are pro grade cordless impact wrenches strong enough to remove stubborn lug nuts, or must I stick to compressed air tools for the job? Any recommendations?

A: Master technician David Gerson of GB Auto Service in Thornhill replies:

Air tools are generally lighter than cordless tools since there’s no electric motor or battery on-board. Their main drawback is they need a compressor, plug-in (or gas engine) power supply and air hose. These are fine for garages, but aren’t much good for roadside tire changes.

Cordless impact wrenches have gotten better in recent years and many shops now use them instead of air tools. Just charge up your battery and these tools can go anywhere. However, the trade-off is that stronger cordless tools are usually heavier and bulkier than lesser units, and most will weigh considerably more than equivalent-rated air tools.

I have a DeWalt 28-volt Nano impact wrench and I’m finding that I use it a lot, even inside the shop where we have ready access to air lines. It’s convenient not needing air hoses that get caught on things and trip up customers and staff. Also, being fully portable, it can work outside in the parking lot or on the road, when necessary.

This unit is about the size and weight of a heavy-duty cordless drill, so it’s easy to handle. It’s rated at 165 lb.-ft. maximum torque and hasn’t had any trouble removing nuts yet. It’s also fine for installing nuts with a torque-stick attachment.

To compare performance, I tried out a Milwaukee 28-volt impact wrench. It’s rated at 325 lb.-ft. maximum torque – comparable to air guns used in most garages. It also has no problem putting tire nuts on or taking them off, but all that power comes at a price. It’s about twice the size and weight of the DeWalt, so constant use in the shop would likely tire out your arm, but for occasional or moderate use that’s not a problem. The hefty strength rating makes it a good choice for tackling severely rusted or seized lug nuts.

Eric Lai adds:

A manual torque wrench or torque stick (a specialized impact wrench attachment), must be used for the final tightening of lug nuts. Check your owner’s manual or a shop service manual for proper torque specifications.

DeWalt pro cordless impact wrenches ( list for $249 to $549; the unit tested is $499. Milwaukee’s versions ( start at $219 and up; the unit tested is $399. A minimum 18-volt tool is recommended for tire lug nuts.

Both units cited are half-inch drive and include two 28-volt batteries and a plug-in charger.

Q: A “no right turn on red” sign was recently installed at the intersection of Enford Road and Elgin Mills in Richmond Hill. Now, northbound traffic on Enford has to wait needlessly to turn right despite enormous gaps when cross-traffic has a green light.

Why the new sign? I don’t see the point.

A: There are only two eastbound lanes on Elgin Mills for traffic, so the “no right on red” prevents drivers turning right from Enford northbound from conflicting with drivers turning left from the opposite southbound dual left-turn lane, which was recently added.

I use that intersection myself and, yes, it is a hassle. If you pretend you’re a through-driver and don’t signal your intention to turn right during the red light, I find the driver behind you, who is usually oblivious to the “no right on red” sign, won’t keep honking for you to go.

Email your non-mechanical questions

to Eric Lai at

Please include year, make, model and kilometres of autos cited, plus your name, address and telephone number.

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