F1 Wheel Gun: The Power Behind Lightning-Fast Tire Changes

As a tuner, garage owner, and motorsports fan, I have always been fascinated by Formula 1, Indy, and tourism car races like NASCAR, DTM, and BTCC pit crew tools.

I thought about sharing the details of a tool that, over the years, has become a pit stop’s star: the mighty motorsport wheel gun.

F1 Wheel Gun

Wheel Guns: A Little History..

Until the mid-60s and early 70s, F1 and Le Man’s sportscars used wheels that were secured by a single wheel nut instead of conventional lug nuts, and it was loosened and tightened using a hammer. People still refer to these wheels as “knock-off” wheels. Changing tires was impractical and excessively time-consuming, so teams didn’t change tires as often as in modern racing.

The air impact wrench was invented in the mid-30s and was meant to be used in the automotive and aviation industries. Impact wrenches played a crucial role during WWII, when workers needed to do tasks repeatedly and fast.

In the 1960s and 1970s, many motorsport teams, such as Brabham Formula 1 and Porsche Le Man’s teams, started using impact wrenches to remove and tighten the wheel nuts quickly. It’s unclear which team introduced impact guns in motorsports, as the technology was developed and adopted gradually over time.

Of course, when it comes to motorsports, there has to be a legend involving Ferrari, and the use of impact wrenches it’s no exception. In the early 70s, Dino Paoli, owner of an Italian tool and racing pit equipment manufacturer, was watching an F1 race on TV and saw how Ferrari was using heavy and slow impact wrenches in the pits. The next day, he phoned Enzo Ferrari and told him, “my company can do something better and make your pit stops faster”. The rest is known history; in 1975, Ferrari started using Paoli’s wheel guns, and his company became the biggest supplier of impact wrenches in the motorsports industry.

Paoli’s impact wrenches helped to reduce F1 pit stop times, and the company became the official supplier of the most important racing teams in the world.

Formula 1 and NASCAR Impact Wrenches

Formula 1 Wheel Nut GunPhoto by: Hafiz Johari/Shutterstock.

Some Facts and Specs

Motorsport impact wrenches have remarkable specs. For example, a Paoli Super 3 wheel gun, the tool used by McLaren F1 Team, produces over 3,000 Nm of torque (2212,68 lb-ft) and spins at about 9,000 RPM. It’s about ten times more powerful than a domestic impact wrench, and it’s sturdy but relatively light (about 3.5kg or 7.7 pounds). Some teams use custom-made impact guns to meet their standards.

Their motor is made of titanium, and the anvil casings are made of carbon fiber or an aircraft-grade alloy. They can endure about 72 races without significant repairs. They are complex pieces of machinery and are usually hand-assembled following strict quality standards.
Formula One Wheel Gun AnvilFormula 1 Wheel Gun Anvil Close-up Photo by: Hafiz Johari/Shutterstock.

F1 tire guns are powered by compressed air or nitrogen, which is more stable, and use a constant air supply of 20-25 bar (290-362 PSI). In 2011 Mercedes started using compressed helium, since it’s lighter and thinner than air and made the guns spin faster. Other teams also began to use it, but besides its high cost, it wasn’t very healthy for the tools and was banned by the FIA the year after.

Before NASCAR stopped using 5-lug wheels in 2022, most teams used Paoli and Ingersoll Rand Thunder guns. They were powerful impact wrenches, but the torque was limited to 700-1,000 NM, although they could spin up to 15,000 RPM. With the introduction of bigger single-lug alloy wheels, NASCAR said farewell to the Ingersoll Rand Thunder guns and established Paoli as the exclusive impact wrench provider for the category, so currently, F1 and NASCAR guns are similar.

Electronics and Data Logging

Electronic systems are usually attached to F1’s pneumatic wheel guns, like Paoli’s DP4000 MG TSA, which use cutting-edge technology to measure the angular rotations of the gun’s drive shaft and the torque transferred at every hammering impact. A dedicated multiprocessor combines the gathered information and measures the absolute torque and angle.

Team engineers could set the gun’s desired torque on the device, and the operator should only pull the trigger until a set of green LEDs is lit, indicating that the wheel nut has been correctly fitted.

It could also switch the impact wrench off when the fastening is complete. However, this would be illegal according to the current F1 rules book. Unlike other racing series, automation of this process is strictly forbidden, so all the responsibility of setting a proper torque and angle relies on the pit crew mechanic operating the gun.

So, in F1, the electronic systems only save the information about how much torque and angle was applied for further review or to monitor excessive over-tightening that could be dangerous during the race.

How Do They Change F1 Tyres So Fast?

One of the most critical moments of any F1 race is the tire change during pit stops. In just a matter of seconds, teams must change the tires on their cars, refuel, and make any necessary adjustments.

Formula 1 pit crews are able to change tires so fast due to a combination of preparation, use of power tools, practice, and teamwork. Teams spend countless hours training and practicing, and honing the tire change procedures with jack and wheel guns, and each member of the pit crew has a specific role to play.

Through efficiency, precision, skill, and seamless coordination, the F1 pit crews are able to change tires in less than 3 seconds, giving drivers a crucial advantage on the track.

Here is a video that shows the work happening behind the scenes.

F1 Tire Changing Operation

During a race, teams use two wheel-guns per wheel; one is on standby as a backup. The guns are color marked to identify which one goes to which wheel. Three mechanics are in charge of each wheel: one operates the F1 wheel gun, the other is in charge of removing the wheel from the car, and the third one installs the fresh wheel so that the wheel nut gun operator can fasten it in place.

The Tyre Gunner (wheel gun operator) pulls the trigger to loosen the wheel nut to remove the old tire, and as soon as he stops squeezing it, the gun automatically switches direction, and it’s ready to tighten the new wheel. The guns have a backup button that allows the operator to manually switch directions if something goes wrong.

Once the new wheel is in place, the wheel-gun operator presses a button on the side of the gun, switching a led indicator that shows the wheel is in place. Some guns automatically light a row of green LEDs as soon as the operator stops pressing the trigger the second time. But the final signal comes from the person operating the gun; he raises his hands, letting the other crew members know the wheel is ready.

When all four wheels are securely in place, and everything is ready, the jackmen put the car back on the floor. If everything is ok, another crew member standing in front of the car gives the driver an “all clear” signal so that the pilot can fly off the pits. All this is done in less than two seconds.

In 2019, Red Bull F1 pit crew replaced all the four wheels of the car driven by Max Verstappen in 1.82 seconds, setting the current pit stop record to beat.

Special Wheel Nuts and Sockets

Teams, especially in Formula One and Indy Car series, have been continuously developing and improving special wheel nuts. When refueling was allowed, pit crew members had more time to replace the wheels because refueling took longer. When the rules changed and refueling was no longer allowed, team engineers had to work on making the wheel replacement procedure even faster because pit stop performance can be key for winning or losing a race.

Impact Wrench used in Car Race
Modern wheel nuts are different for the rear and front wheels, and the thread section has been reduced to a minimum to prevent cross-treading. This was further improved when the wheel nuts started to be embedded in the wheel, reducing misalignment issues and making the mechanics’ task even faster.

Each team develops its own engagement systems, and their impact guns use special wheel gun sockets designed to engage the wheel nut safely and fast. Wheel gunners can already have their guns in motion as they engage the wheel nut. To minimize the risk of rounding the nuts and other accidents, F1 wheel nuts are made of hard steel or titanium.

The left side of the car uses left-handed threads, and the right side uses right-handed threads to prevent the nuts from coming loose.

Safety Operation

Teams take measures to minimize risks as much as possible, pit crew members wear gloves, eye, and ear protection, and they train not only to improve their speed but also to prevent accidents.

The amount of torque of these impact wrenches is extremely high; however, the wheel nuts and the axle tips are so strong and well calculated that there are few accidents due to over-torquing and wheel nuts are used only one time, so it doesn’t matter if they end up suffering some damage after being handled.

Over the last decade and after thousands of successful procedures, two cases drew the attention of F1 fans and people worldwide. In 2018, at Bahrain’s Grand Prix, Ferrari’s pit crew struggled to remove a wheel nut on the rear left wheel of Kimi Raikkonen’s car. The incident forced Kimi to retire, and further analysis determined that the problem was caused by a cross-threaded wheel nut. Ferrari redesigned the wheel nut and changed its pit stop training and procedures.

The last notorious incident happened at the 2021 Monaco Grand Prix. That time Mercedes Benz’s driver Valtteri Bottas entered the pits in second place, but the mechanics couldn’t remove the front right wheel because the wheel nut’s pockets that made contact with the impact wrench’s socket were destroyed, and it was impossible to remove it. After a long time in the pits, Bottas was forced to retire.

The team left the wheel in place for further analysis in the factory and removed it a week later. The press had a field day, but I think it’s pretty unfair, given all the engineering and training behind this technology. Accidents can happen, of course, but something beautiful about the motorsports industry is that they always learn from their mistakes.