Taiwan Leading Hand-Tool Maker

Which Brand Provides the Most Powerful Impact Wrench? (comparison table for 2019 models of leading brands)

  • 2019-05-03

In the last five years, we have witnessed three major developments in the field of pneumatic impact wrench (air impact wrench) and electric impact wrenches. These are listed below.

1.) Thanks to structural improvements, the torque of air impact wrenches continues to grow considerably.

2.) Increased popularity of power impact wrenches, due to structural improvements and extended battery life.

3.) Compact impact wrenches remain popular, being light and portable in confined spaces.

As a result, many tool brands keep introducing air impact wrenches and power impact wrenches. Below is the first page of Amazon search results for impact wrenches, including pneumatic (air), power and cordless impact wrenches.


Which is more powerful—air or power impact wrenches?

The comparison table below lists the maximum torques of various brands’ 2019 models of pneumatic and power impact wrenches, grouped according to drive size.  (To know more about drive size: Socket Size Basic Knowledge)

We have selected these brands from personal experience. Thus, many leading brands premium tool brands have not been included. If you have any additional data to share with us, please feel free to contact us by e-mail: service@tien-i.com



The above chart shows maximum torque measured using two different methods:

1.) Max tightening torque denotes the maximum torque an impact wrench can deliver when tightening a screw under test conditions. This data should be collected in a controlled laboratory environment.

2.) Nut-busting torque refers to a tool's ability to remove a bolt that’s been tightened using methods other than the tool in question. To measure nut-busting torque, a bolt is tightened with a torque wrench calibrated to 1100 ft-lbs and subsequently removed with the tool being tested.

Generally speaking, tightening torque should be lower than removal torque. Applying excessive tightening torque may cause bolt damage or screw stripping. When tightening a bolt, it’s advisable to use lower torque in order to avoid possible damage.


The 1/4" impact wrench is rare because of the lower torque requirements. The maximum torque is 136 Nm, so far.

For example, the minimum DIN/ISO torque requirement for a 1/4" Dr x 13mm impact socket is 80.4 Nm. A good quality impact socket can achieve 1.5 times the minimum torque, which is 120.6 Nm. Impact Wrench torque 136 Nm could be too much to drive all small size bolts or nuts.

3/8" Dr. (9.5mm)

Currently, the 3/8" compact impact wrench is gaining market popularity. Many brands are focusing on introducing lightweight models and these are commonly seen in auto shops. Do not underestimate compact models. At the time of writing, compact models have torques as high as 746 Nm. This is more than sufficient for 3/8" DR impact sockets.

For example, the ISO/DIN minimum torque required for a 3/8" DR x 25mm impact socket is 280 Nm. A good quality impact socket can handle 1.5 times torque tolerance, which comes to 420 Nm. Applying 746 Nm is likely to break the screw or even the impact socket.

1/2" Dr. (12.7mm)

Currently, the 1/2" DR impact wrench is king, regardless of whether it’s a pneumatic or a power impact wrench. Various styles are available, including compact and electric, and these range from 18V to 20V. The various models’ maximum torques range from 186 Nm to 1762 Nm, because the 1/2” DR covers a wider range of nut sizes.

The table below shows the relationship between nut size and the lowest torque of an impact socket. The minimum size is 8mm (M5) and the maximum is 32mm (M22).

For example, the lowest torque value the 1/2" DR impact socket size from 19mm to 34mm can afford is 650 Nm. We can estimate the 1.5 times value at about 975 Nm. With a wrench torque of over 1000 Nm, even the large size 1/2" DR impact socket risks being cracked.

Is it necessary to use such a high torque?

In the BMW tires auto shop, the standard for tightening tire torque ranges from 80 ft-lbs to 120 ft-lbs (or 108 Nm to 163 Nm).

Some tire shop operators think they can save time by immediately using the highest torque of the impact wrench. To do so is dangerous, as it may cause the screw to collapse or slip. Moreover, tightening with higher torque means that it will require higher torque to loosen the screw, thus increasing the wear (and potential damage) to bolts and screws in the long run. Some might consider the potential damage to the screw worthwhile in comparison to the risk of malfunction, especially when driving long distances.



The above table shows the torques of various brands’ power and air impact wrenches. However, torque is not the only aspect to consider. When buying an impact wrench, we recommend that you also bear in mind the following points:

1.) What is the purpose? Do you plan to use it on a construction site, for carpentry or to repair a car? What is the maximum torque required for the task at hand? It is not recommended to seek a higher torque than necessary, and a heavier and bigger wrench body costs more money as well.

2.) How much does it weigh? You will need to be comfortable holding this weight for prolonged tasks. Try holding up two bottles of water for 15 minutes and imagine whether you would be able to do so for an hour or longer.

3.) How convenient is the upkeep and maintenance? Check the warranty.

4.) How long is the battery life? How big and how heavy are the batteries? When you’re working on a construction site all day, you don’t want to carry a bunch of batteries. If you’re not that clear about battery specifications, simply pay attention to the two number values—the higher the volts (V) and amp hours (Ah), the better.

If you’re still not sure which impact wrench would be best suited for your task, please consult with a local hardware shop that has a good reputation and ask a staff member for recommendations. Conduct further research on brand comparison tests.

Tien-I has been producing impact sockets for leading brands worldwide since 2003. Our standards exceed European (DIN/ISO) and American (ANSI) torque requirements. We are happy to collaborate with various industries on the development of new tools. If you’re interested in our quality impact sockets, please contact our knowledgeable sales team.

Note: This article is based on personal observation. We welcome your updates and corrections. Please feel free to contact us by e-mail at: service@tien-i.com.