It’s been a long time coming and, in the opinion of most tire industry engineers, long past due. Bias ply truck tires are officially relics of a past age.
Early truck radials were tailored for over-the-road service, and their robust tread, sidewall and internal reinforcement materials soon outperformed even the best bias unit. Then mixed-service and off-highway versions of the new tires appeared, further diminishing the bias market. Finally, specialty radials eventually replaced bias designs, even in demanding service conditions.
The final bias tire holdout has been the container chassis industry. Now a new proposed rule recently propogated by the Federal Motor Carrier Safety Administration (FMCSA) is expected to provide a significant incentive to switch this price-conscious market to radials hopefully all the way to low-profile, tubeless radials.
The new rule is expected to clarify that chassis owners are responsible for safety-related maintenance of equipment including tires.
It’s not that bias ply tires are inherently unreliable or problem prone; they’re just technically obsolete. Most chassis-hauling truckers have complained about the poor condition of the chassis they are given at ports and rail terminals, with faulty tires, etc.
Chassis owners have complained that better tires placed on their units are often “requisitioned” by truckers for their own use, replaced with well-worn or even junk tires when the chassis is returned. Colored rubber stripes and sidewall branding of “For Trailer Use Only has been tried to increase security, but the low initial cost of tube-type bias ply tires endured until recently.
From a technology and performance view, it’s generally true that tubeless bias tire designs don’t fare as well as tube-types. For radials, the opposite is true. Liability concerns have made multi-piece wheel designs required for tube-type tires quite scarce. This has caused some users to convert to radials. Industry shipment records show bias ply tires (nearly all tube-type) currently account for less than 5% of the replacement medium truck market and a scant 1% of the OE side.
Bar coding, radio frequency identification or other electronic asset tracking security systems will likely contribute to the final exit of bias tires. And that will usher in a new purchasing and maintenance approach for chassis owners specifically lifecycle cost analysis vs. low up-front pricing.
Where retreading of bias casings has been practiced to some degree, radial casing designs are widely acknowledged to be more durable and superior for multiple retreads. Fuel economy benefits are an added bonus. The free-rolling trailer tire positions of a typical 18 wheeler can contribute up to half of the total tire rolling resistance for the rig and improvements in the 3% to 5% range should be realized. Quality radials can make container chassis more reliable and efficient, while reducing downtime and improving safety.
With a switch to radials, many chassis owners and their dealers should be prepared for changes. While it is true that less overall servicing may be required, the basics of inflation pressure checks and inspections for damage/wear are essential and must be performed routinely. Premature loss of radial casings will have a bigger dollar impact and tend to negate potential savings from upgraded tires.
Since the new FMCSA rule is expected to shift responsibility to chassis owners, education, training, and documented maintenance records may be required at many locations. Chassis owners not familiar with rigorous tire maintenance programs should seek input from tire company field engineers or trucking companies that also own chassis. It’s a good bet they’ve already made the switch to tubeless radials in the quest for lower operating costs.