Mounting a wheel seems simple enough. Pop it on, use a torque wrench to tighten the lug nuts, and you’re good to go. But this step is a lot more crucial than you think. You want to be sure the wheel is mounted correctly and maintained properly to increase safety at the wheel end. We have a few simple tips that can help you make sure your wheels are road-ready.
WHY IS PROPER WHEEL INSTALLATION IMPORTANT?
Making sure that your wheels are installed properly is crucial for your fleet, their safety, and the safety of the other drivers on the road. Having a wheel-off can be the outcome of a bad installation but can be easily avoided. Did you know: Common causes of wheel-offs include problems with fasteners or bearings. A failed bearing could be due to improper installation, over- or under-tightening, or a loss of lubricant. Semi-truck lug nuts can become loose over time, especially if installed incorrectly. Some causes include excess rust, paint, or dirt that build up and cause a loss of clamping force on the lug nuts. Keeping fasteners clean is vitally important in maintaining the force that keeps tires in place. Clamping force may also be reduced through incorrect torquing, tightening sequences, or routine torque checks.
After several incidents, the National Transportation Safety Board conducted a study on the causes of wheel-offs. They found that in 83% of incidents between 2000 and 2003, maintenance or repairs had been performed just before the separation occurred. Avoiding poor maintenance and ensuring that wheel integrity and installation meet rigorous standards can be a major component in preventing wheel-offs.
Between successful maintenance, installation, and tools, you can reduce your risk of a wheel-off on one of your vehicles.
Best Practice for Wheel Safety Guide
Wheel-end maintenance is crucial to having a safe fleet. Our Best Practice Guide for Wheel Safety can help!Download the guide
PROPER WHEEL MOUNTING & INSPECTION – STEP BY STEP
To accurately mount the tire and rim and prevent wheel-offs, inspection is key. Following appropriate checks and procedures can mean the difference between a tire that stays fixed in place and one that could separate at high speeds. TIA has provided an easy guideline you can follow called RIST.
- R – Remove Debris
It is important to inspect the surface of the wheel and remove any debris or rust on the mating surfaces that may affect the clamping force when the wheel is installed. Look over all areas such as the inside surface of the wheel hub, mounting surfaces, and mating plate on the backside of the wheel. You can remove small amounts of dust and debris with a stiff wire brush.These materials frequently find their way into older wheels, which are often refinished to prevent rust and corrosion. A wheel that was incorrectly refinished can be challenging to work with. Excess powder coating can trap materials underneath, and the coating may build up on wheel mounting surfaces and in bolt holes. Pay attention to the coating when mounting a wheel, ensuring that there are no cracks in the finish or rust underneath it.
- I – Inspect Surfaces
After making sure all mounting surfaces are clean, you should look for damage, including any bending or irregularities in the bead seat or flange wear and corrosion. Also, check the disc wheel. A crack between the bolt holes can cause failure as a result of loose inner cap lug nuts. When these are loose, it means the fastener was not tightened adequately. Look for perfectly rounded stud holes, too. If the holes are elongated, the stud has been stretched out before and can no longer hold the right level of tension.Drivers can play a part, too, by taking the time to inspect tires daily. Signs of problems include:
- Lubrication leaking on the inner wheel
- Excessive or abnormal wear
- Rust coming out from a wheel stud
- Discoloration on the window of the hubcap
- Missing oil caps
- Signs of the wheel slipping around the flange nut
Inspect the wheel again when mounting to make sure the hub is completely clean of any materials that can lead to a loss in clamping force
- S – Snug Lug Nuts by Hand
It is important to snug the lug nuts by hand in the proper star pattern before applying torque. This will prevent cross-threading to the lug nut and will ensure that the wheel and fasteners are properly centered to prevent any damage to the threads.When it’s time to fasten the studs, check for quality. Studs and threads should be in good condition and match the size requirements for both the wheel in use and the lug nuts. If you are replacing any damaged studs, you’ll also need to replace the two adjacent studs. If any more than two studs need replacing, you’ll have to swap out all 10 of them. You’ll also need to ensure that the hub pilots don’t have any damage or excessive wear that would cause the mounting to be off-center.You can reuse some parts if you inspect them thoroughly for quality and safety. Studs and lug nuts should be good condition, with no thread damage or stretching, and bearings should be examined for drag on the rollers and other signs of damage or wear.
If you’re mounting a pair of wheels, make sure that the diameter on each is the same. Any small difference can contribute to premature tire wear, which will result in loss of fuel economy.
- T – Torque to Spec
Proper tools are essential, especially during the torquing process. Using a power tool to tighten the lug nuts is acceptable, but you should never use an impact wrench to achieve the final torque. Only use calibrated torquing tools. A proper torque wrench must be used to add the correct amount of pressure.When you torque, you add tension, and applying both torque and friction to the stud creates a clamping force. Appropriate clamping force is necessary, as this is what keeps the tire in place. Too much or too little force can cause the fasteners to fail, and they both behave similarly.TMC has specified fastener recommendations between 300 and 900 ft/lbs. You’ll need to check these based on the type of wheel, fastener, and procedure you will use. Sometimes, however, these need to be adjusted according to the installation process, manufacturer recommendations, or fleet specifications.
It may seem that having a tighter stud may be more secure, but in reality, over-torquing is a serious hazard, as it stretches the stud. When the stud is stretched, it loses its spring force, and the clamping force can become dangerously low. Use calibrated tools to prevent over-torquing and too-low clamping force.
Another component that can affect torque is the replacement parts that you choose. Studs and nuts should be OEM-quality and uniform. When checking your torque, pay attention to the movement of the wheel as it rotates. Any side-to-side movement can lead to a wobbly wheel once it hits the road. A runout gauge can help you measure the trueness of the wheel, ensuring that the radius is consistent.
WHEN TO RE-TORQUE YOUR LUG NUTS
One crucial step in keeping tires safely on a truck is to re-torque the wheel nuts 50 to 100 miles after installation. Any dust, dirt, debris, or paint that were present during installation may have worked themselves out and reduced the clamping force by this point. The wheel also settles into place and can create subtle changes in the setup.
Over time, driving can cause lug nuts to become loose, so it’s important to be aware of any lug nuts that need to be retorqued. Our preventative solution for this is CHECKPOINT. CHECKPOINT is a clear, visual indicator that fits onto a lug nut and shows movement over time. This system of markers includes arrows attached to each lug nut that points directly to adjacent arrows. When the points become misaligned, you can see which specific nut has become loose. This visual tool helps you see a loose lug nut find before it becomes hazardous. CHECKPOINT can be placed on lug nuts in a Point to Point design, or in a Daisy Chain design, as shown below
OUR PREDICTIVE MAINTENANCE SOLUTION
Wheel-offs are a serious concern but can be avoided with proper wheel installation. With the appropriate tools, processes, and our simple solution, CHECKPOINT, you can prevent an unanticipated and potentially catastrophic event on the road.
Download our Best Practice Guide to see visual step-by-step instructions to making sure your wheels are safe!