This blog was provided exclusively to CCJ by Joe Puff, vice president of truck technology and maintenance, NationaLease.
Tire mounting procedures are extremely important and you should always comply with OEM and OSHA regulations when mounting and balancing tires. OSHA has very specific requirements outlining tire procedures (OSHA 29 CFR 1910.177). These must be followed to ensure the safety of the technicians who mount and balance tires and to ensure the tires and wheels operate safely when on the truck is on the road. Make sure your shop has the tire safety posters and instructions for mounting and dismounting posted.
There are, however, some things you can do to make tire mounting and balancing go more smoothly. Some technicians wonder whether they need to use bead lubricant when mounting tires. The answer is yes, unless the tire or wheel manufacturer recommends against it. Here’s why:
- It reduces friction between the tire bead and the rim during installation. This reduces bead-chipping damage, which can allow air migration into the inner liner and cause tire failure.
- It allows the tire to evenly center itself on the rim with a secure seal. Without the lube, the tire bead rubber can grab the rim and allow the tire to mount slightly off center. This causes tire balance issues, runout problems, and uneven tire wear.
When selecting a tire bead lubricant, be sure to choose a quality product designed specifically to be used as a bead lube. I’ve seen a variety of lubricants used, from ether and gasoline to common sprays. Some of these products are extremely dangerous, and some can cause tire and wheel damage. Again, that’s why it is important to choose a product that is designated as a tire bead lube.
There are a number of products that are not made for the job and should never be considered for tire mounting including:
- Mineral spirits or other petroleum products which can deteriorate rubber, are flammable, and can be dangerous.
- Certain soaps can cause corrosion to the rim and damage the bead rubber. Some lubes can cause the tire to slip on the wheel.
In addition to choosing the right product, you also need to make sure the bead areas are clean, and that rust and scaling are removed before adding the bead lube.
When installing a wheel, a little dirt or rust on a stud or nut can have a significant effect on the wheel’s clamping force. Be sure the wheel mating surfaces are clean and free of rust or corrosion, including the wheel mounting surface as well as the brake drum surface, studs, nuts, etc.
There also seems to be some confusion about torque vs. clamping force. Clamping force is often confused with the torque of a bolt or stud nut. Many people believe if they torque a nut or bolt to the OE specified value that the proper clamping force will be achieved.
Don’t be fooled: the two values are totally different. Torquing a clean nut and bolt to a specified torque will result in significantly more clamping force than a damaged, dirty, or rusty nut and bolt torqued to the same torque value. Be sure to start with clean, rust and damage-free studs and nuts, and consult the manufacturer for condition allowances and procedures.
Since wheel torque is another key component for ensuring proper wheel life and safety, make sure to get it correct. If there is not enough torque, the nuts can back off. Torque too tightly and the studs can stretch. Once stretched studs can continue stretching over time. Don’t think you are safe if you exceed the manufacturers torque recommendation. Whether too little or too much torque, clamping force can be altered causing significant issues.
There are many different wheel torque values based on the wheel type and manufacturer, so always refer to the OEM recommendations. Remember to also follow the recommended torque sequence.
Tire mounting and balancing are critical to the safe operation of the vehicle, but a little attention to the details ensures you’ll get it right.