Can Bright Ideas for Passenger Tires Apply to Commercial Markets?
While away from home recently, I hopped into a shiny new rental car. My ride was a complimentary upgrade luxury model.
In short order, I pulled over to the side of the road after deciding that I was too distracted trying to locate the controls to perform basic functions – turning on the headlights, defroster, radio and map lights. I was used to reaching for these things effortlessly in my familiar ride and wondered why each new car has to be so confusing.
The short answer is that someone had a better idea, or at least thought so. Do most of the changes we see in our industry really result in improvement? Or, are they simply changes for the sake of making changes?
It wouldn’t surprise me if some young engineer soon “discovered” that headlight-dimmer switches could be cleverly located on the floor to free both hands for other activities.
However, some clever ideas, covering a wide gamut – from practical safety enhancements to sheer gimmickry – have been tried in tires, mostly in non-truck applications, over the years.
Chines have been used, primarily on certain aircraft tires, to direct water spray on wet runways away from jet-engine intakes. These integrally molded rubber sidewall sculptures are tailored to particular airframe bodywork and engine placement and have been used mostly for military applications.
They can be very effective in altering water-spray patterns, but studies to expand usage to commercial truck tires seem to have been abandoned, as under-chassis airflow and gap space (with resulting downdraft) between the tractor cab and trailer front have been identified as primary variables in the spray from truck tires on wet highways.
Have you noticed that closely coupled aero tractors with tank skirts and cab extenders produce less spray, especially when pulling height-matched van trailers? Although it seems as if open-car haulers in particular might benefit from chine-equipped tires, a drawback is that these tires would be directional (outside mount only), since the sidewall deflector would interfere with steering and suspension components.
Reflective sidewalls have been marketed, primarily on bicycle and motorcycle tires. Most have been high-quality, embedded glass-bead sidewall rings that enhance nighttime visibility. The round tire shape would seem less likely to be confused with stationary objects than the linear tape stripes or point light sources commonly used as side markers. Fire trucks, other emergency vehicles and trucks operating on secondary roads might benefit from these reflecting ‘hoops.’ Cost has been cited as an obstacle, but perhaps it’s worth a new look.
Colored rubber laminates in the tread that indicate a certain tread depth or wear condition have been developed for passenger car tires, although use has been minimal. Since radial truck tires are complex structures, containing 12 or more different rubber compounds, engineers are understandably reluctant to add another (and non-essential) compound to the mix, especially one that is new or dissimilar.
Another concern is that, while such a feature might allow users to identify a tire that reaches a designated pull point, everyone else could also make the same observation, perhaps to the detriment of conscientious users whose tires reached their wear-out point in the middle of a cross-country run.
One feature that has been successfully transferred from small, light-duty tires to heavy-duty truck models is a self-sealing liner that allows the tire to stay in operation even with multiple punctures, as long as the injury does not impair the casing’s structural integrity. This works admirably for typical nail holes and other small damages that would otherwise cause air loss and unscheduled downtime. However, negatives include added tire weight, possible balance issues and additional costs. These tires offer increased reliability and short payback periods for some mixed-service applications, such as waste collection.
Another interesting solution for enhanced winter traction, especially on icy road conditions, was offered by at least one large truck- and bus-tire manufacturer in the 1960s. Each of the major circumferential ribs contained a molded-in steel coil that wore with the rubber tread, thus offering an exposed steel traction edge for icy surfaces.
These are some of the innovations applied to tire designs over the years. In the case of commercial truck tires, however, the main emphasis has historically been on slowly evolving, tried-and-proven concepts.
