While we normally think “tires” when discussing OTR, rims need your attention too.
Working with OTR tires is like dealing with a pressure cooker, only the ingredients we put into it are excessively heavy rubber and big rims. Although they’re equally important when it comes to making sure your equipment is safe and performing well, we tend to focus on the tires. But to help ensure the safety of your workforce and the security of OTR equipment, the rims need equal attention, and that means regular inspections.
We’re at work on a manual for our certification program that will go into greater depth, showing pictures of out-of-service rims and how to determine whether a rim should remain in service, be sent out for further inspection and repaired, or just plain scrapped.
Rim failure
Rims get damaged because they’re subject to severe use carrying massive loads on mining sites, quarries, and anywhere else the OTR sector is, and are subject to intense heat. Too many technicians use a steel hammer to hit on their components, but the hammer heads are harder than the rims, so it puts in microscopic risers that develop small cracks that can lead to rim failure. Rim failure is a major risk. It takes 9 lb.-ft. of pressure to break your arm, and a 29-inch tire aired up to about 60 psi produces about 370,000 lb.-ft. of force. That makes it vital to know when the rims should remain in service.
Always remember to clean the rims and all components when you take off a tire; always inspect the rim, lock ring, band seat, and flanges looking for physical damage. Check the manufacturer’s recommendations, and use the gauges they supply to know if they can return to service. Match the markings to the rims and rim bases.
Safety equipment
Clean everything, including the lock ring and O-ring channels, while wearing proper safety equipment including face shields, gloves and long-sleeved shirts. It’s OK to use a drill with your wire brush to speed up the process, but always wear a face shield. A needle scaler works well, or just old-fashioned elbow grease with wire brushes is fine too. Excessive rust and corrosion on rims and damaged lock ring channels are the most common issues you’re likely to find.
When you’re putting it all back together and seating the components, always use a dead blow hammer to lightly tap on the lock ring to make sure it locks into the lock ring groove. Always use a remote-control air device with a lock-on air chuck with a sufficient amount of hose to stay safely out of the trajectory zone.
Never weld rims! Welding weakens the metal, and rims must be sent out to a full-service repair shop for proper inspection and repair.
Tracking techniques
Finally, track the results of your inspections by serial number, and stay on top of what should have been repaired, what repairs were made, and whether anything needs replacing.
Taking care of your fleet means paying attention to more than just where the rubber hits the road; it’s every component of your rims from band seats to lock rings. Everything that holds the rims together has the potential to impact you and everyone around you. Don’t take chances!
Remember—we have one of the most dangerous jobs in the world and work on the largest tires on the planet. Always do a complete cleaning and rim inspection on all equipment—it could save your life! As always, be safe out there. Your family is counting on you to come home safely.
