1/2 or 3/8 Torque Wrench For Lug Nuts – A Mechanics View


I’ve been a mechanic for over twenty years, and I use my torque wrench many times a day. If you buy a good one, you won’t ever need to buy another.

A 1/2 inch torque wrench with a working range of 30 to 160 ft. lbs. is the correct size tool for lug nuts and other heavy fasteners.

Torque wrenches are not just for the Pro. The days of tightening a nut or bolt by feel or guessing are over.

The cost of these type specialized tools have come way down, so now it makes sense to own one. Especially as some of you may know, that sickening feeling when you over-tighten a bolt, pull the threads, or break the bolt.

Torque wrench

Repairing that kind of damage can be expensive and soul-destroying. I still remember the taste of my medicine. Anyway, here’s a link to my favorite 1/2 inch Teng torque wrench you might find useful. It links to Amazon, and truthfully I was surprised at the price. I paid more than this for mine many years ago.

What Makes A Good Torque Wrench?

There are a number of important factors to consider when choosing a torque wrench, but the most important consideration – What range do I need? The torque range of the wrench will dictate the drive size. 1/2 inch is pretty standard for larger fasteners like automotive and truck lug nuts.

A torque wrench won’t be accurate at the very top or bottom of its range, so bear that in mind when choosing your wrench. You’ll need about 10 ft. lbs. to spare. Common torque wrench drive sizes include 1/4, 3/8, 1/2, and 3/4 inches. All have different applications.

The 1/4 and some 3/8 inch drive wrenches will be measured in inch lbs., not ft. lbs… They’re designed for lighter fasteners requiring less torque. (12-inch lbs. is equal to 1-foot lb.) The 1/4 inch drive torque wrench is used for very light fasteners, like interior trim, control module covers, etc.

The 3/8 drive is perfect for engine work like timing belt assembly, front covers, water pumps, cam covers, oil pans, etc. The 1/2 is ideal for heavier type fasteners like lug nuts, suspension, steering, engine mounts, etc.

The 3/4 isn’t used in automotive. It’s reserved for oversized fasteners found on large vehicles like Semi and earth-moving equipment, etc.

Torque wrench chart

Most automotive lug nuts are tightened to 90 – 120 ft. lbs… Trucks will be more, about 120-150 ft. lbs. range.

If you’re running a truck, consider buying the 1/2 inch larger wrench with a greater working range of 30 to 250 ft. lbs., you’ll find plenty of other uses for the greater range.

As a mechanic, I know what I want in a torque wrench. Here’s a bulleted list of what’s important to me.

  • Flexible Working Range
  • All Metal Body
  • Certified Accuracy
  • Ratcheting Head
  • Stamped Easy Read Scale
  • Solid Haptic & Audible Click
  • Hatched Metal Handle
  • Angle Measuring Head
  • Solid Storage Case
  • Great Warranty

Understandably, a feature like an angle measuring head may not be important to the occasional user. It likely won’t be used unless you undertake larger repair jobs like replacing a head gasket.

Correct Lug Nut Torque Procedure

Wheel torque sequence chart

While you already know the value of using a torque wrench, some people might say it’s not strictly necessary to torque your lug nuts. I don’t agree.

Sure it’s OK in an emergency to tighten your lug nuts using your car’s wheel changing kit, but I advise calling a tire shop and have them back off the wheel lug nuts and torque them to spec.

And here’s why – Most vehicles will use the tension of the wheel rim against the hub to keep the brake rotor aligned. If the wheel lug nuts are torqued out of sequence and to different specs, it’s possible to cause the rotor to have run out (wobble).

This will only be slight but can cause vibration, pulsing in the brakes, road-noise, the brake rotor, and pad damage. When torquing a wheel, Snug all lug nuts down first before using the torque wrench. Then tighten in a star formation. This helps the wheel, Rotor and Hub align squarely.

Why I Love My Teng Torque Wrench

Wheel torque

I’ve had my Teng wrench for a few years now. It gets calibrated every year, and I’ve never had a problem. It’s not an ornament. It’s used heavily but still performs and looks good. I’m happy to recommend it. It’s a good kit.

Here’s why I love it – First off, it’s made of alloy – no plastic bits to break. The measurement scale is in ft. lbs… On the opposite side, it’s measured in Nm. The scale is stamped into the barrel, so it’s not going to wear away, and I can read them clearly.

The ratchet head has a degree measurement tool built in. Traditionally this would be a separate tool altogether. You’ll use this feature when torquing down cylinder head bolts on cars or trucks. The spec sheet might say, torque the head bolts to 100 ft. lbs. and on the 2nd pass, torque to 90°.

Comes with a solid plastic case and a detailed instruction sheet. The Teng torque wrench comes with a lifetime warranty. I like how the Teng 10-150 ft. lbs. feel. It’s a quality tool. You can tell by holding it. You’ll notice how confident and definite the action is. When it reaches the set torque, it clicks clearly.

If you need a greater torque range, this Teng wrench covers 25-250 ft. lbs… It’s the same quality wrench.

How To Use The Teng Torque Wrench?

Your torque wrench is a precision tool and should be stored in its molded case, it will arrive with full instructions, but it isn’t difficult to master. You can use regular 1/2 sockets; however, you’ll find deep sockets work best on lug nuts.

If you’re very particular about your wheel rims, get a set of ABN non-scratch 1/2 inch impact sockets.

  • Unlock your Teng torque wrench by turning the lock to the left.
  • Adjust the wrench to the closest required measurement on the main shaft scale.
  • Then use the handle scale to adjust to exact specification needed.
  • Each mark on the twist handle is 1 ft. lbs.
  • When set, lock the torque wrench using the handle lock.
  • Torque wrench is now ready for work.
  • Torque your fastener, using even steady pressure.
  • A solid click indicates the correct torque achieved.

Caring For Your Torque Wrench?

Spare wheel tools

This is a precision bit of kit. Dropping it on the ground like you would a hammer is going to knock it out of calibration. Although the torque wrench is not unlike a ratchet, it’s not a ratchet. I don’t use it to open bolts, only tighten to spec.

I clean mine every use, store it on a shelf where I can grab it real fast. Come winter. I’ll spray it with WD40 and keep it in its hard case to keep moisture off it. You may want to store yours in the trunk. If so, store it securely.

Best to return the Torque wrench to the bottom of the scale range when it’s not in use. This relieves the tension on the components. The tool requires calibration every year when working it professionally, but as an occasional user, you won’t need to.

You can check out all the tools I use, including a torque wrench and workshop manuals, here on the Mechanics tools page, or check out the Amazon link below.

Amazon Mechanics Torque Wrench

Related Questions

How many pounds of torque do I need to remove lug nuts? About 300 ft. lbs. of torque delivered by an impact wrench should be enough. More torque may be needed if the lug nuts are corroded or over-tightened.

Do I need a torque wrench? A torque wrench should always be used to check and adjust the wheels. Tightening by hand is OK, but the wheel should be torqued to specification as soon as it is practical.

You may find these posts useful:

How to change a flat wheel

Are wheel lock nuts worth it?

John Cunningham

John Cunningham is an Automotive Technician and writer on Rustyautos.com. I've been a mechanic for over twenty-five years, and I've worked for GM, Volvo, Volkswagen, Landrover, and Jaguar dealerships. My passion is cars. I use my knowledge and experience to write articles that help fellow gear-heads with all aspects of car ownership, including buying advice, maintenance, and troubleshooting.

Recent Posts