Over the past several years, a range of products have been introduced into the marketplace designed to be used inside truck tires for a variety of purposes. These include sealants to prevent losing air pressure; internal balancing materials - such as powders, liquids, gels and/or beads - for ride enhancements; and tire coolants, said to reduce running temperatures.
To help users better identify and understand the potential consequences and concerns associated with these products, the Technology & Maintenance Council (TMC) has developed its Recommended Engineering Practice RP 246, Considerations for Products Intended for Use Inside Tires. This RP also offers evaluation guidelines for the selection of materials intended for use inside truck tires.
RP 246 applies to products designed for use inside the contained air cavity of tubeless radial truck tire/wheel assemblies on commercial vehicles with a gross vehicle weight rating of more than 10,000 pounds.
A technical council of American Trucking Associations (ATA) – the largest national trade association for the trucking industry, TMC is North America’s premier technical society for truck equipment technology and maintenance professionals.
TMC Recommended Practices (RPs) are specifications or practices to assist equipment users, vehicle and component manufacturers and other industry suppliers. There are two types, the adoption of which, is voluntary.
Recommended Maintenance Practices are concerned with the maintenance of commercial vehicle equipment, and also include informational documents that cover technical aspects of maintenance, equipment and supporting technologies.
Recommended Engineering Practices pertain to the design, specification, construction and performance of commercial vehicle equipment.
“Before selecting a product for use inside tires, it is important to obtain accurate information about what benefits a product of this type can and cannot deliver, as well as any effects it may have on tire mounting and other maintenance practices,” states the RP 246. “Accordingly, TMC recommends obtaining results for comparison from experienced users with similar service conditions and equipment.
“Since these materials will be in constant contact with both tire and wheel interior surfaces, issues such as chemical compatibility, abrasion resistance, corrosion and possible material changes must be considered for tire, wheel, valve and other components.”
Basically, there are three general categories of products for us inside truck tires, TMC says.
1. Sealants - These are intended to slow inflation loss caused by small punctures and bead leaks in both tubeless and tube tires. Historically, notes TMC, sealants have been “used in mixed service or off-road applications where tires are subjected to penetrations, cuts or other hazards that can cause loss of inflation pressure, especially in conditions that make immediate or in-route repairs difficult or dangerous.”
Sealants vary in composition, typically being either liquid, a liquid with suspended solids, semi-solid or gel.
2. Balancing and ride improvement materials - These are designed to replace traditional, external balance weights. When installed, the material - typically in the form of a powder, liquid or tiny beads - is intended to distribute itself on the balance requirements of the individual tire as the load and speed changes, making the tire self-balancing.
3. Coolants - These are meant to reduce the running temperatures of tires so as to help increase tire durability and tread life.
TMC’s Recommended Practice RP 246 does not get into determining the validity of performance claims for the different brands and types of tire additives. It does, however, provide a number of questions that potential users of these products would be well-advised to ask any prospective suppliers.
Among the questions:
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